List of possible malfunctions |
Diagnostics |
Elimination Methods |
The crankshaft does not rotate with the starter |
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The battery is empty | The voltage at the battery terminals with consumers switched off is below 12 V. When the starter is turned on, a crackling sound can be heard from under the hood |
Charge the battery; if it doesn't charge, replace it |
Decreased battery capacity | The voltage at the battery terminals with the consumers turned off is more than 12 V, but when the starter is turned on, it drops below 6-8 V. At the same time, crackling may be heard from under the hood | Charge the battery with low current (no more than 1 A); if the capacity is still insufficient, replace |
Oxidation of the battery terminals, loose fit | When the starter is turned on, a voltage of more than 0.5 V appears between the battery terminals and its terminals (measured with a voltmeter). There may be a crackling noise coming from under the hood | Tighten the terminals, clean the contact surfaces, lubricate them with technical vaseline |
Engine jam | Turning the crankshaft by the nut of its pulley, make sure that it rotates | Repair the engine |
Damaged starter drive gear or flywheel teeth | Inspection after removing the starter | Replace starter or flywheel |
The starter traction relay control circuit is faulty: the wires are damaged, their tips are oxidized or loose, the contacts do not close «30» and «50» ignition switch or faulty starter enable relay | When the ignition key is turned to position «starter» traction relay does not work (no click under the hood). Check if 12 V is supplied to the control contact of the traction relay | Strip, crimp the tips of the wires; replace the faulty ignition switch or its contact part, the faulty starter relay |
Faulty starter traction relay: short circuit or open in the retracting winding, sticking of the relay armature (anchor misalignment, surface contamination, corrosion, etc.) | When the key is turned to position «starter» traction relay does not work (no click under the hood), but 12 V is supplied to the control contact of the traction relay. Remove the starter, relay, check its operation | Replace defective traction relay |
The contacts of the traction relay or wires are oxidized, poor contact «masses» | When the starter is turned on, a click is heard under the hood, but the starter armature does not rotate. Check circuit resistance with an ohmmeter «battery - starter», including wire «masses». If the circuits are good, remove the starter and check the operation of its relay | Tighten the wire ends, crimp the terminals. Replace defective relay |
Open or short circuit in the holding winding of the starter relay | When the starter is turned on, a crack is heard from under the hood. Battery voltage is within normal limits. The relay is checked with an ohmmeter or by its excessive heating | Replace starter relay |
Burning of the starter collector, hanging brushes or their strong wear | Starter armature does not rotate or rotates slowly (First make sure that the traction relay is working, for which you can supply power to the starter contact bolt, bypassing the relay. Caution, avoid sparks near the battery!). On the removed starter, check the brush pressure to the commutator, their residual height, commutator wear |
Clean the burnt collector with fine-grained glass sandpaper, rinse with unleaded gasoline. Ensure free movement of the brushes in the slots. If the manifold is very worn, replace the starter |
Open or short circuit in the winding of the starter armature | Starter armature does not rotate or rotates slowly (First make sure that the traction relay is working, for which you can supply power to the starter contact bolt, bypassing the relay. Caution, avoid sparks near the battery!). The health of the winding is checked with an ohmmeter or by darkening of the insulation |
Replace starter |
Freewheel slip | When the starter is turned on, the armature rotates, the flywheel is stationary | Replace clutch or starter |
The ring gear rotates on the flywheel | When the starter is turned on, the ring gear rotates, the flywheel and crankshaft are stationary. A screeching sound is heard from the clutch housing | Replace flywheel |
Loud noise during starter operation |
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The starter is skewed to the engine, its fastening is loose or the cover on the drive side is broken | Inspection | Tighten the threaded connections to the specified torque, if the cover breaks, replace the starter |
Loose starter pole (anchor touches him) | Disassemble the starter, inspect, check the alignment of the poles and the gap between them and the anchor | Retighten poles or replace starter |
Excessive wear on bearing bushings or armature shaft journals | Inspection after disassembling the starter | Replace starter |
The ring gear rotates on the flywheel | When the starter is turned on, the ring gear rotates, the flywheel and crankshaft are stationary. A screeching sound is heard from the clutch housing | Replace flywheel |
Worn starter drive gear teeth or - more often - flywheel crown | Inspection after removing the starter | Replace starter or flywheel |
The gear does not disengage from the flywheel: sticking of the drive lever, weakening or breakage of the freewheel clutch spring or starter traction relay, clutch sticking on the splines of the armature shaft or traction relay core, malfunction of the ignition switch (contacts do not open «30» and «50»), starter enable relay | Check if the voltage is removed from the control contact of the starter relay when the ignition key is released, if the key returns to the position «ignition». The opening of the ignition switch contacts can be checked with an ohmmeter. If the voltage at the starter traction relay disappears when the ignition is turned off, remove and disassemble the starter to check | Replace starter traction relay or starter assembly; ignition switch contact group or switch assembly, starter enable relay |
The crankshaft is turned by a starter, but the engine is not started up |
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There is no fuel in the tank | According to the indicator and control lamp of the fuel level | Top up fuel |
The battery is empty | The crankshaft is turned by a starter very slowly. The voltage at the terminals of the battery when the consumers are off is below 12 V | Charge the battery; if it doesn't charge, replace it |
Decreased battery capacity | The crankshaft rotates very slowly. The voltage at the battery terminals when consumers are off is more than 12 V, but when the starter is turned on, it drops to 6-8 V | Charge the battery with low current (no more than 1 A); if the capacity is still insufficient, replace |
Oxidation of the battery terminals, loose fit | The crankshaft is turned by a starter very slowly. When the starter is turned on, a voltage of more than 0.5 V appears between the battery terminals and its terminals (voltmeter check) | Tighten the terminals, clean the contact surfaces, lubricate them with technical vaseline |
Increased resistance to rotation of the engine crankshaft: scuffs on shafts, liners, parts of the cylinder-piston group; shaft deformation; frozen engine oil; jammed alternator or coolant pump | The crankshaft is turned by a starter very slowly.
If the weather is cold, and the day before the engine was running steadily and without extraneous noise, most likely the cause of increased resistance to rotation is frozen oil. In this case, you can try to start the engine with a second battery (see end of section «Diagnostics»). After starting, do not allow the engine to run at high speeds and watch the oil pressure warning lamp: if it lights up while the engine is running, immediately stop it for 1-2 minutes so that the thickened oil has time to drain into the sump. If abnormal noises are heard when starting or running the engine, check the free rotation of the coolant pump and alternator pulleys. In case of extraneous noise in the area of the block or cylinder head, disassemble the engine |
Use engine oil according to climatic conditions. If the coolant pump is stuck, replace the pump cover with impeller, if the generator is stuck, replace the bearing or generator assembly. In case of scuffing on shafts, liners, parts of the cylinder-piston group, deformation of the shafts, replace the defective parts, find out and eliminate the cause of their failure |
[K] Malfunction in the low voltage circuit | Check with a voltmeter whether power is supplied to the ignition coil and switch. If not, check the circuit from the battery to the ignition coil with an ohmmeter (through the ignition switch and the ignition relay) and further to the switch | Strip oxidized tips, tighten loose wire fasteners, replace damaged wires, ignition switch or its contact part, ignition switch relay |
[K] Faulty spark torque sensor | Determined by a voltmeter (see Ignition system) or replacement sensor to a known-good | Replace defective sensor |
[K] Faulty circuit «switch - sparking torque sensor» | Checked with an ohmmeter | Strip oxidized terminals, tighten loose wire fasteners, replace damaged wires |
[K] Faulty switch | Substitute a known-good switch | Replace defective switch |
Damage to the insulation of high-voltage devices and circuits - no sparking | [K] Having securely fastened the end of the high-voltage wire at a distance of 8-10 mm from «masses» car, crank the engine with a starter (do not touch high voltage circuits!). between wire and «weight» should spark regularly (Use only known-good high-voltage wires for testing). If there is no spark at the output of the ignition coil, the coil is faulty, if at the output / outputs of the ignition distributor, the rotor or distributor cap is faulty. The breakdown of the rotor or cover is determined by burnouts or cracks on their surface. Health of the rotor resistor (1 kOhm) checked with an ohmmeter.
[B] Test with a known-good high voltage wire and ignition module |
Replace faulty ignition coil [K] / ignition module [B], damaged high voltage wires. Heavy Duty (salt on the roads, frost alternating with thaws) it is advisable to replace the wires every 3-5 years.
[K] Clean the distributor cover and rotor from dirt and moisture, blown rotor resistor, broken rotor, cover - replace |
The high voltage wires are connected to the distributor[K] / ignition module[B] in the wrong order; disconnected wire | Inspection | Connect the wires according to the firing order of the cylinders |
The gap between the electrodes of the candles does not correspond to the norm | Gap 0.7-0.8 mm [K] or 1.0-1.1 mm [B] checked with a feeler gauge | By bending the side electrode, set the desired gap or replace the candles |
Defective candles | A faulty candle, as a rule, can be identified by the color of soot on the insulator. The absence of external damage and sparking between the electrodes on an inverted candle does not allow us to conclude that it is working | Replace defective spark plugs |
[K] Incorrect ignition timing | See General information, Ignition system | Adjust ignition timing |
Struck valve timing | Check the alignment of the marks on the crankshaft and camshaft (see Engine) | Set the correct relative position of the shafts (by tags) |
[B] Defective engine control unit, its circuits or crankshaft position sensor (rarely - coolant temperature sensor) | Check if 12V is being supplied to the control unit (see Connection diagram of the VAZ-21214 engine management system with multiport fuel injection for Euro-2 toxicity standards with controller 2123-1411020-10 (type MP 7.0) on cars VAZ-21214), crankshaft position sensor circuit,
no damage to the sensor itself and the gap between it and the ring gear
crankshaft (1+0.2 mm). The resistance of a good sensor is 500-700 ohms.
In the event of a break in the temperature sensor or its circuit, the electric fan of the cooling system operates continuously |
Replace faulty unit, sensors, wires |
[B] Faulty idle speed controller or circuit | The lamp may be on. When starting the engine, lightly press «gas», by opening the throttle. If the engine starts, but stalls when the pedal is released, the regulator is faulty |
Replace defective regulator |
[B] Blown injection fuse or fuse | Inspection: check the fusible link - a piece of black wire, a non-switchable power fuse and a main relay fuse | Check the circuits and devices of the injection system, eliminate the cause of burnout, replace the fuse |
[B] Starting the engine is blocked by the immobilizer | The red LED continues to flash, indicating that the armed mode is on | The immobilizer, even in the locked state, allows at least one engine start (for more details, see the description of the immobilizer operation in the vehicle operation manual). You can start the engine by installing a new control unit |
Fuel filters are clogged, water in the power system has frozen, hoses are pinched, fuel lines are deformed.
[K] Faulty fuel pump |
When cranking the engine with a starter, there is no smell of gasoline from the exhaust pipe.
[K] There is no gasoline in the carburetor float chamber - when you press «gas» there is no jet of fuel from the accelerator pump nozzle. [B] Availability of gasoline (under pressure) in the fuel rail can be checked by briefly pressing the spool of the fitting at the end of the rail (remember that gasoline is flammable!) |
In winter, roll the car into a warm garage, blow (tire pump) supply system from the fuel pump to the gas tank [K], replace the fuel pump or its diaphragms [K], defective hoses and pipes |
[B] Poor contact in the fuel pump supply circuit (including wires «masses») or its relay is faulty | Checked with an ohmmeter | Strip the contacts, crimp the terminals, replace the faulty relay, wires |
[B] The fuel pump does not pressurize the system properly | Check fuel pump outlet pressure (not less than 3.5 kgf/cm2), make sure the strainer of the fuel pickup is clean | Clean the fuel gauge screen. The fuel pump which does not provide the necessary pressure in system - replace |
[B] Defective injectors or their circuits | Check the injector windings and their circuits with an ohmmeter (no break and short circuit) | Replace faulty injectors, ensure contact in electrical circuits |
[K] Faulty carburetor solenoid or no voltage when ignition is turned on | See Carburetor Solenoid Valve Control System in section Electrical equipment | Replace the faulty valve, EPHX control unit, ensure contact in the electrical circuits. When tightening the valve, do not apply much force so as not to deform the seat of the jet and the jet itself |
[K] Faulty or misadjusted carburetor starter or actuator | See Carburetor engine power system | Adjust trigger (see Carburetor engine power system), replace worn parts |
[K] Clogged jets and carburetor passages. Loosely wrapped jets, solenoid valve | Inspect, blow channels and jets | Rinse with gasoline or acetone and blow through the jets, if heavily soiled, clean them with a fishing line or softwood needle. Screw jets tightly (do not damage the thread and jet!) |
Intake of foreign air into the intake manifold | Inspect the joints, check the fit of the hoses, fittings, tightness of the clamps. At the time of starting, turn off the vacuum brake booster by pinching the corresponding hose | Torn gaskets, parts with deformed flanges, defective vacuum booster Replace |
[K] Excessive fuel level in the carburetor float chamber | There is a strong smell of gasoline from the exhaust pipe, a cold engine starts better than a hot one.
Remove the top cover of the carburetor, check the tightness of the float, its ease of movement and the absence of touching the walls of the float chamber. Checking the tightness of the needle valve: turn the carburetor cap upside down and pump gasoline with the fuel pump lever. The slightest leak of gasoline from under the needle or valve base is unacceptable |
Replace needle valve, adjust fuel level in float camera See Carburetor engine power system |
[K] Too rich mixture due to gasoline leaking into the engine crankcase through a torn fuel pump diaphragm | The oil on the dipstick smells like gasoline, the low oil pressure lamp may light up at low engine speeds | Replace the fuel pump or its diaphragms; if there is a lot of gasoline in the oil, then the oil |
[K] In cold weather, the engine starts easily, but immediately stalls |
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The carburetor starter is faulty or unadjusted: the air damper does not open slightly at the first flashes in the cylinders | Inspection with the air filter housing cover removed (do not approach the face - a flash is possible!). Indirect check - when pulling the air damper on a warm engine, it immediately stalls and starts with difficulty | Adjust starter, replace worn parts |
Engine starts for a long time |
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[K] Evaporated gasoline from the carburetor float chamber (after a long stay, especially in hot weather) | — | After a long period of parking, pump up gasoline with the fuel pump manual priming lever |
[B] The fuel pump does not create the necessary pressure in the system, the fuel filters are clogged, the hoses are pinched, the fuel lines are deformed, the injectors are leaking | Check the pressure in the fuel rail with a pressure gauge (2.5-3.2 kgf/cm2 at idle and 3-4 kgf / cm2 at medium speed), inspect the fuel lines for fuel leaks | Replace filters, eliminate kinks in hoses; fuel pump that does not provide the desired pressure in the system and with low performance - replace. Replace defective injectors |
Engine runs erratically or stalls at idle |
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The gap between the electrodes of the candles does not correspond to the norm | Gap 0.7-0.8 mm [K] or 1.0-1.1 mm [B] is checked with a round feeler gauge | By bending the side electrode, set the desired gap or replace the candles |
Strong soot on the electrodes of the spark plugs; ingress of soot particles into the gap between the electrodes | Inspection. By soot, you can, as a rule, determine the performance of the candle and the condition of the engine | Clean spark plugs with compressed air or mechanically (do not damage the insulator!). Identify and eliminate the cause of increased carbon formation in the combustion chamber, replace the spark plugs if necessary |
Defective spark plugs: leakage current through cracks in the insulator or carbon deposits on the thermal cone, poor contact in the center electrode assembly | A faulty candle, as a rule, can be identified by the color of soot on the insulator. The absence of external damage and sparking between the electrodes on an inverted candle does not allow us to conclude that it is working | Replace defective spark plugs |
Damage to the insulation of high-voltage devices and circuits - interruptions in sparking | [K] Having securely fastened the end of the high-voltage wire at a distance of 8-10 mm from «masses» car, crank the engine with a starter (do not touch high voltage circuits!). between wire and «weight» should spark regularly (Use only known-good high-voltage wires for testing). If there is no spark at the output of the ignition coil, the coil is faulty, if at the output / outputs of the ignition distributor, the rotor or distributor cap is faulty. The breakdown of the rotor or cover is determined by burnouts or cracks on their surface. Health of the rotor resistor (1 kOhm) checked with an ohmmeter.
[B] lamp may light up (incorrect oxygen sensor signal). To check the high-voltage wires and the ignition module, replace them with known good ones |
Replace faulty ignition coil[K] / ignition module[B], damaged high voltage wires. Heavy Duty (salt on the roads, frost alternating with thaws) it is advisable to replace the wires every 3-5 years.
[K] Clean the distributor cover and rotor from dirt and moisture, blown rotor resistor, broken rotor, cover - replace |
The high voltage wires are connected to the distributor[K] / ignition module[B] in the wrong order; disconnected wire | Inspection | Connect the wires according to the firing order of the cylinders |
Struck valve timing | Check the alignment of the marks on the crankshaft and camshaft (Engine) | Set the correct relative position of the shafts (by tags) |
Low compression in the engine cylinders (less than 10 kgf/cm2): wear or damage to valves, seats, hydraulic bearings of valve levers [B]; wear, sticking or breakage of piston rings | Using a compression gauge, we measure the compression in the engine cylinders, warmed up to operating temperature, by turning the crankshaft with the starter while the pedal is fully depressed «gas» | Replace rings, pistons.
Repair cylinders. Lap the valves to the seats, if necessary, replace the valves, their guide bushings, grind the seats. [B] Blow out the oil supply channels to the hydraulic bearings of the valve levers, if necessary, replace the hydraulic bearings |
[K] Faulty switch | Substitute a known-good switch | Replace defective switch |
[B] Faulty engine control unit, its circuits, throttle position sensor, injectors (windings burned out or atomizers heavily contaminated) | Check if 12V is being supplied to the control unit (see Connection diagram of the VAZ-21214 engine management system with multiport fuel injection for Euro-2 toxicity standards with controller 2123-1411020-10 (type MP 7.0) on cars VAZ-21214), nozzle operation (see Injection engine power system), electrical circuits and sensors | Replace the faulty unit, sensors, wires, injectors. Dirty nozzles can be washed on a special stand |
[B] Faulty idle speed controller or circuit | The lamp may be on. Substitute a known-good regulator | Replace defective regulator |
[K] Clogged jets and carburetor passages. Loosely wrapped jets and solenoid valve | Determined by inspection, purge of channels and jets (see Carburetor engine power system) | Blow out the jets, if heavily soiled, clean them with a fishing line or a needle made of soft wood. Clean the crankcase ventilation system. Screw jets tightly (do not damage the thread and jet!) |
[K] Faulty solenoid valve or its circuit, EPHX control unit | Actuation of the valve is determined by a click when voltage is applied or - on the removed valve - by moving the core (see Carburetor engine power system, electrical equipment) | Ensure reliable contact in the EPHX control circuit, faulty valve, EPHX control unit - replace. When tightening the valve, do not apply much force so as not to deform the seat of the jet and the jet itself |
[K] Engine idle control out of order | See Carburetor engine power system | Adjust idle (Carburetor engine power system) |
Rupture of the rubber sealing ring on the mixture quality screw | Inspection | Replace ring |
Intake of foreign air into the intake manifold | Inspect the joints, check the fit of the hoses, fittings, tightness of the clamps. At the time of starting, turn off the vacuum brake booster by pinching the corresponding hose | Torn gaskets, parts with deformed flanges, defective vacuum booster Replace |
[K] Excessive fuel level in the carburetor float chamber | There is a strong smell of gasoline from the exhaust pipe, a cold engine starts better than a hot one.
Remove the top cover of the carburetor, check the tightness of the float, its ease of movement and the absence of touching the walls of the float chamber. Checking the tightness of the needle valve: turn the carburetor cap upside down and pump gasoline with the fuel pump lever. The slightest leak of gasoline from under the needle or valve base is unacceptable |
Replace leaky needle valve, adjust float chamber fuel level (Carburetor engine power system) |
[K] Insufficient fuel level in the carburetor float chamber | See Carburetor engine power system | Adjust fuel level (Carburetor engine power system) |
[K] Too rich mixture due to gasoline leaking into the engine crankcase through a torn fuel pump diaphragm | The oil on the dipstick smells like gasoline, the low oil pressure lamp may light up at low engine speeds | Replace the fuel pump with its diaphragm; if there is a lot of gasoline in the oil, then the oil |
[B] Faulty fuel pressure regulator (the drain channel is constantly open) | Check the pressure in the fuel rail with a pressure gauge (2.5-3.2 kgf/cm2 at idle and 3-4 kgf / cm2 at medium speed) | Replace failed regulator |
[B] Exhaust leak (area to the oxygen sensor) | Inspection at medium engine speeds | Replace defective manifold gasket, tighten seals |
[B] Oxygen sensor defective: sensitive element poisoned or destroyed, air suction hole clogged, heating coil burnt out, electrical circuits faulty | The lamp is on. You can roughly evaluate the operation of the sensor with an autotester: the integrity of the heating coil is checked with an ohmmeter, the output voltage is checked with a voltmeter (connect the voltmeter without breaking the circuit, for example, by piercing the wires with thin needles). see also Injection engine control system. Check if the air intake hole is blocked (anticorrosive, dirt, etc.) | Repair damaged electrical circuits, clean the air intake hole.
Replace defective sensor |
[B] Faulty speed sensor | After stopping the car, the engine runs unevenly, but soon the idle speed stabilizes | Replace sensor |
[K] Valve clearance not adjusted | The sound of valves is heard in the area of the cylinder head cover | Adjust gaps |
[B] Valve lever hydraulic bearings not working: gap between lever and cam is too large | The sound of valves is heard in the area of the cylinder head cover. It is possible to finally judge the malfunction of the hydraulic support only after it has been checked (see Engine) | Blow out the channels for supplying oil to the hydraulic lifters, if necessary, replace the hydraulic lifters |
Camshaft lobes wear | Inspection after partial disassembly of the engine | Replace camshaft |
[K] Weakening or breakage of the springs of the weights of the centrifugal automatic distributor of the ignition, damper rings of the weights are lost, sticking of the weights | Visually and on a special stand | Replace ignition distributor |
[K] Fuzzy operation of the vacuum ignition timing machine: when the vacuum is removed, the plate does not return to its original position, large play in the bearing | Inspection. The characteristic of the vacuum regulator is taken on a special stand | Eliminate jamming, replace faulty vacuum machine or ignition distributor assembly |
Low idle |
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[K] Engine idle control out of order | See Carburetor engine power system | Adjust idle (see Carburetor engine power system) |
[K] Incorrect ignition timing | See General information, Ignition system | Adjust ignition timing |
[K] Excessive fuel level in the carburetor float chamber | There is a strong smell of gasoline from the exhaust pipe, a cold engine starts better than a hot one.
Remove the top cover of the carburetor, check the tightness of the float, its ease of movement and the absence of touching the walls of the float chamber. Checking the tightness of the needle valve: turn the carburetor cap upside down and pump gasoline with the fuel pump lever. The slightest leak of gasoline from under the needle or valve base is unacceptable |
Replace leaky needle valve, adjust fuel level in the float chamber (Carburetor engine power system) |
[K] Clogged fuel or air carburetor idle jet | Inspection | Flush with unleaded gasoline or acetone and blow out jets and channels of the idle system, clean the crankcase ventilation system |
[K] Broken rubber o-ring on mixture screw | Inspection | Replace ring |
[K] Loose carburetor solenoid valve, damaged o-ring | Inspection | Replace the ring, tighten the valve without applying much force so as not to deform the seat of the jet and the jet itself |
[B] Faulty idle speed controller or circuit | The lamp may be on. Substitute a known-good regulator | Replace defective regulator |
[B] Faulty fuel pressure regulator | Check the pressure in the fuel rail with a pressure gauge (2.5-3.2 kgf/cm2 at idle) | Replace failed regulator |
Increased resistance to air flow in the intake tract | Check air cleaner element, intake tract (absence of foreign objects, leaves, etc.) | Clean the intake tract, replace the dirty air filter element |
Intake of foreign air into the intake manifold | Inspect the joints, check the fit of the hoses, fittings, tightness of the clamps. At the time of starting, turn off the vacuum brake booster by pinching the corresponding hose | Torn gaskets, parts with deformed flanges, defective vacuum booster Replace |
High idle |
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[K] Engine idle control out of order | See Carburetor engine power system | Adjust idle (see Carburetor engine power system) |
[K] Faulty or misadjusted carburetor starter | See Carburetor engine power system | Adjust trigger (see Carburetor engine power system), replace worn parts |
[K] Loose carburetor solenoid valve | Inspection | Tighten the valve without applying much force so as not to deform the seat of the jet and the jet itself |
Seizure of weights of the centrifugal regulator of an advancing of ignition | Inspection of the regulator after disassembly | Eliminate jamming, if necessary, replace the sensor-distributor assembly |
[K] Long driving at high engine speeds | After 1-2 minutes of idling, the speed drops to normal | Not a malfunction |
Throttle actuator malfunction [K], throttle [B] | Check the stroke of the gas pedal, the gap in the drive, make sure that there is no jamming in the drive | Replace defective parts, lubricate seizing drive parts with engine oil |
Throttle valve of the second chamber of the carburetor [K] / throttle valve [B] does not fully close | The gap between the throttle valve and the walls of the mixing chamber [K] / throttle assembly [B] is visible through the light | [K] With the stop screw of the damper, achieve its complete closure . In this case, the damper should open easily, without jamming. At the end of the adjustment, fill the screw with paint. [B] Check that the throttle actuator has free play, adjust if necessary. Throttle valve adjustment is not recommended at home |
[K] Carburetor dampers are mounted on axes with a misalignment and do not close at any position of the stop screws | Inspection | Contact a service station or replace the carburetor |
Foreign objects getting under the throttle valve | Inspection | Remove foreign object, check damper operation |
[B] Faulty idle speed controller or circuit | The lamp may be on. Substitute a known-good regulator | Replace defective regulator |
[B] Defective throttle position sensors, mass air flow sensors or their circuits | In the event of a break in the sensors or their circuits, the lamp lights up. In the event of a break in the throttle position sensor, the engine idle speed does not drop below 1200 min-1, with a break in the mass air flow sensor - below 2000 min-1, however, this almost does not affect the driving performance of the car. If both sensors fail, despite the high idle speed, the car is only barely able to move on its own | Restore contact in electrical circuits, replace the faulty sensor (sensors) |
[K] Clogged idle air jet | Inspection | Rinse with unleaded gasoline or acetone and blow through the jet. If heavily soiled, clean it with a fishing line or soft wood needle. Flush the crankcase ventilation system |
[B] Increased pressure in the fuel lines due to a malfunction of the pressure regulator or its pneumatic line, deformation of the tubes, kink in the drain hose | Inspection, checking the pressure gauge in the fuel rail (no more than 3.2 kgf/cm2 at idle) | Replace the defective regulator, tubes, eliminate the kink in the hose, restore the integrity of the pneumatic line |
[B] Nozzle leaks (overflow) | Check injectors (Injection engine power system) | Replace faulty injectors |
[K] While the vehicle is in gear
engine stops when gas pedal is released (at forced idle)
(see also «Engine runs erratically or stalls at idle») |
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Faulty EPHX control unit or its circuit | See Carburetor Solenoid Valve Control System in section Electrical equipment | Replace failed unit |
[K] In hot weather, the engine spontaneously stops and starts with difficulty |
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Steam plug in the power system. The fuel drain line to the tank does not work: tubes, hoses are clogged or pinched, «stuck» check valve | Inspect the fuel lines, blow out the line with a tire pump | Eliminate kinks in hoses, replace deformed tubes, defective check valve |
The engine does not develop full power and does not have sufficient throttle response.
Jerks and dips when driving a car |
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[K] Engine not warm | By temperature gauge | Warm up the engine to operating temperature |
[K] Insufficient fuel level in the carburetor float chamber | When the suction button is pulled out, jerks and dips decrease or disappear completely | Adjust fuel level |
[K] Clogged jets and carburetor passages. Jets not tightly wrapped | Inspect, blow channels and jets | Rinse with gasoline or acetone and blow through the jets, if heavily soiled, clean them with a fishing line or softwood needle. Screw jets tightly (do not damage the thread and jet!) |
Intake of foreign air into the intake manifold | Inspect the joints, check the fit of the hoses, fittings, tightness of the clamps. Disconnect the vacuum brake booster for a short time by pinching the corresponding hose (Caution: the effort on the brake pedal will increase significantly!) | Torn gaskets, parts with deformed flanges, defective vacuum booster Replace |
[K] Faulty or misadjusted starting device or its drive | See Carburetor engine power system | Adjust trigger (see Carburetor engine power system), replace worn parts |
[K] Excessive fuel level in the carburetor float chamber | There is a strong smell of gasoline from the exhaust pipe, a cold engine starts better than a hot one. Remove the top cover of the carburetor, check the tightness of the float, its ease of movement and the absence of touching the walls of the float chamber. Checking the tightness of the needle valve: turn the carburetor cap upside down and pump gasoline with the fuel pump lever. The slightest leak of gasoline from under the needle or valve base is unacceptable | Replace needle valve, adjust fuel level in float camera (see Carburetor engine power system) |
[K] Too rich mixture due to gasoline leaking into the engine crankcase through a torn fuel pump diaphragm | The oil on the dipstick smells like gasoline, the low oil pressure lamp may light up at low engine speeds | Replace the fuel pump, its diaphragms; if there is a lot of gasoline in the oil, then the oil |
Partial throttle [B] / dampers [K] | Determined visually on a stopped engine | Adjust throttle actuator |
[K] Defective accelerator pump or injector, clogged carburetor fuel passages | Check the pump flow, no leakage of gasoline from under the diaphragm. Make sure that the accelerator pump lever moves freely | Replace damaged parts, tighten threaded connections, purge valves |
[K] Incorrect ignition timing | See General information, Ignition system | Adjust ignition timing |
Struck valve timing | Check the alignment of the marks on the crankshaft and camshaft (see Engine) | Set the correct relative position of the shafts (by tags) |
Low compression in the engine cylinders (less than 10 kgf/cm2): wear or damage to valves, seats, hydraulic bearings of valve levers [B]; wear, sticking or breakage of piston rings | Using a compression gauge, we measure the compression in the engine cylinders, warmed up to operating temperature, by turning the crankshaft with the starter while the pedal is fully depressed «gas» | Replace rings, pistons. Repair cylinders . Lap the valves to the seats, if necessary, replace the valves, their guide bushings, grind the seats .
[B] Blow out the channels for supplying oil to the hydraulic bearings, if necessary, replace the hydraulic bearings of the levers |
The gap between the electrodes of the candles does not correspond to the norm | Gap 0.7-0.8 mm [K] or 1.0-1.1 mm [B] is checked with a round feeler gauge | By bending the side electrode, set the desired gap or replace the candles |
Strong soot on the electrodes of the spark plugs; ingress of soot particles into the gap between the electrodes | Inspection. By soot, you can, as a rule, determine the performance of the candle and the condition of the engine | Clean spark plugs with compressed air or mechanically (do not damage the insulator!). Identify and eliminate the cause of increased carbon formation in the combustion chamber, replace the spark plugs if necessary |
Defective spark plugs: leakage current through cracks in the insulator or carbon deposits on the thermal cone, poor contact in the center electrode assembly | A faulty candle, as a rule, can be identified by the color of soot on the insulator. The absence of external damage and sparking between the electrodes on an inverted candle does not allow us to conclude that it is working | Replace defective spark plugs |
[K] Wear, damage to the contact carbon in the ignition distributor cap. Coal spring weakened | Inspection | Replace distributor cap or ember with spring |
Damage to the insulation of high-voltage devices and circuits - interruptions in sparking | [K] Having securely fastened the end of the high-voltage wire at a distance of 8-10 mm from «masses» car, crank the engine with a starter (do not touch high voltage circuits!). between wire and «weight» should spark regularly (Use only known-good high-voltage wires for testing). If there is no spark at the output of the ignition coil, the coil is faulty, if at the output / outputs of the ignition distributor, the rotor or distributor cap is faulty. The breakdown of the rotor or cover is determined by burnouts or cracks on their surface. Health of the rotor resistor (1 kOhm) checked with an ohmmeter.
[B] lamp may light up (incorrect oxygen sensor signal). To check the high-voltage wires and the ignition module, replace them with known good ones |
Replace faulty ignition coil[K] / ignition module[B], damaged high voltage wires. Heavy Duty (salt on the roads, frost alternating with thaws) it is advisable to replace the wires every 3-5 years.
[K] Clean the distributor cover and rotor from dirt and moisture, blown rotor resistor, broken rotor, cover - replace |
[K] Faulty switch | Substitute a known-good switch | Replace defective switch |
[K] Weakening or breakage of the springs of the weights of the centrifugal automatic distributor of the ignition, damper rings of the weights are lost, sticking of the weights | Visually and on a special stand | Replace ignition distributor |
[K] Fuzzy operation of the vacuum ignition advance machine: when the vacuum is removed, the plate does not return to its original position | Inspection. The characteristic of the vacuum regulator is taken on a special stand | Eliminate jamming, replace faulty vacuum machine or ignition distributor assembly |
There is little fuel in the tank | According to the indicator and control lamp of the fuel level | Top up fuel |
Clogged fuel filters, frozen water in the power system, pinched hoses, deformed fuel lines | Check fuel lines, replace filters. Fuel rail pressure [B] can be checked with a pressure gauge (2.5-3.2 kgf/cm2 at idle and 3-4 kgf / cm2 at medium speed) | In winter, roll the car into a warm garage, blow (tire pump) power supply system from the fuel pump to the gas tank [K], replace defective hoses, pipes, filters |
[K] The fuel pump does not create the necessary pressure in the system | See Carburetor engine power system | Replace the fuel pump or its diaphragms |
[B] The fuel pump does not pressurize the system properly | Check fuel pump outlet pressure (not less than 3.5 kgf/cm2), make sure the strainer of the fuel pickup is clean | Clean the fuel gauge screen. Replace the fuel pump that does not provide the required pressure in the system |
[B] Poor contact in the fuel pump supply circuit (including wires «masses») or its relay is faulty | Checked with an ohmmeter | Strip the contacts, crimp the terminals, replace the faulty relay, wires |
[B] Defective injectors or their circuits | Check the injector windings and their circuits with an ohmmeter (no break and short circuit) | Replace faulty injectors, ensure contact in electrical circuits |
[B] «floating» malfunction of the crankshaft position sensor or its circuits | The lamp is on. Clean the sensor rod from metal dust, check the gap between it and the crankshaft ring gear (1±0.2mm). Check sensor resistance with an ohmmeter (500-700 ohm) or substitute with a known good one | Restore contact in electrical circuits, replace the faulty sensor |
[B] Faulty injection coolant temperature sensor or circuit | Check the resistance of the sensor with an ohmmeter at different temperatures (see See Injection engine control system). In the event of an open in the circuit or sensor, the lamp lights up and the electric fans of the cooling system operate continuously | Restore contact in electrical circuits, replace the faulty sensor |
[B] Defective throttle position sensors, mass air flow sensors or their circuits | In the event of a break in the sensors or their circuits, the lamp lights up. In the event of a break in the throttle position sensor, the engine idle speed does not drop below 1200 min–1, with a break in the mass air flow sensor - below 2000 min–1, however, this almost does not affect the driving performance of the car. If both sensors fail, despite the high idle speed, the car is only barely able to move on its own | Restore contact in electrical circuits, replace the faulty sensor (sensors) |
[B] Faulty engine control unit or its circuits | Check if 12V is being supplied to the control unit (see Connection diagram of the VAZ-21214 engine management system with multiport fuel injection for Euro-2 toxicity standards with controller 2123-1411020-10 (type MP 7.0) on cars VAZ-21214). Substitute a known-good unit to test the unit | Replace failed unit |
[B] Faulty fuel pressure regulator | Check the pressure in the fuel rail with a pressure gauge (2.5-3.2 kgf/cm2 at idle and 3-4 kgf / cm2 at medium speed) | Replace failed regulator |
[K] Valve clearance not adjusted | With an increased gap, the knock of the valves is heard in the area of the cylinder head cover. | Adjust gaps |
[B] The valve lever hydraulic bearings are inoperative: the gap between the lever and the cam does not correspond to the calculated | With an increased gap, the knock of the valves is heard in the area of the cylinder head cover. With a small gap on the non-working surface of the camshaft cams (opposite ledge) visible signs of wear | Blow out the channels for supplying oil to the hydraulic bearings, if necessary, replace the hydraulic bearings of the levers |
Strong wear of the camshaft cams | Inspection after partial disassembly of the engine | Replace worn camshaft |
Sediment or broken valve springs | Inspect the springs, measure their length in a free state and under load | Replace weak or broken springs |
Pops in the intake manifold |
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[K] Incorrect ignition timing | See General information, Ignition system | Adjust ignition timing |
[K] Faulty switch | Substitute a known-good switch | Replace defective switch |
[K] Clearances in the intake valve drive are small | On non-working (cylindrical) the surfaces of the camshaft cams show signs of wear. | Adjust gaps |
[B] Inlet valve lever hydraulic bearings not working: gap between lever and cam is too small | Inspection of the camshaft - non-working surface of the cams (opposite ledge) must not show obvious signs of wear | Replace the hydro bearings of the levers |
[B] High oil pressure (stuck oil pump relief valve), due to which the hydraulic bearings of the levers do not allow the valves to close under the action of the springs | The pressure can be measured by connecting a pressure gauge to the oil line of the hydraulic chain tensioner. At any engine speed, the pressure should not exceed 5 kg/cm2 | The pressure can be measured by connecting a pressure gauge to the oil line of the hydraulic chain tensioner. At any engine speed, the pressure should not exceed 5 kg/cm2 |
Inlet valves sticking in bushings: resinous deposits on the surface of the valve stem or bushing, sediment or broken valve springs | Inspect the valve stems, springs, measure their length in a free state and under load | Inspect the valve stems, springs, measure their length in a free state and under load |
Struck valve timing | Check the alignment of the marks on the crankshaft and camshaft (see Engine) | Set the correct relative position of the shafts (by tags) |
Shots in the silencer |
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[K] Incorrect ignition timing | See General information, Ignition system | Adjust ignition timing |
[K] Faulty switch | Substitute a known-good switch | Replace defective switch |
[K] Clearances in the exhaust valve drive are small | On non-working (cylindrical) the surfaces of the camshaft cams show signs of wear. | Adjust gaps |
[B] Exhaust valve lever hydraulic bearings not working: gap between lever and cam is too small | Inspection of the camshaft - non-working surface of the cams (opposite ledge) must not show obvious signs of wear | Replace the hydro bearings of the levers |
[B] High oil pressure (oil pump pressure relief valve stuck), due to which the hydraulic bearings of the levers do not allow the valves to close under the action of the springs | The pressure can be measured by connecting a pressure gauge to the oil line of the hydraulic chain tensioner. At any engine speed, the pressure should not exceed 5 kg/cm2 | Repair oil pump |
Valves sticking in bushings: resinous deposits on the surface of the valve stem or bushing, sediment or broken valve springs | Inspect the valve stems, springs, measure their length in a free state and under load | Replace weak or broken springs, clean valve stems with acetone or nitro thinner, replace valves if necessary, ream bushings with special reamer |
Struck valve timing | Check the alignment of the marks on the crankshaft and camshaft (see Engine) | Set the correct relative position of the shafts (by tags) |
Damage to the insulation of high-voltage devices and circuits - interruptions in sparking | [K] Having securely fastened the end of the high-voltage wire at a distance of 8-10 mm from «masses» car, crank the engine with a starter (do not touch high voltage circuits!). between wire and «weight» should spark regularly (Use only known-good high-voltage wires for testing). If there is no spark at the output of the ignition coil, the coil is faulty, if at the output / outputs of the ignition distributor, the rotor or distributor cap is faulty. The breakdown of the rotor or cover is determined by burnouts or cracks on their surface. Health of the rotor resistor (1 kOhm) checked with an ohmmeter.
[B] lamp may light up (incorrect oxygen sensor signal). To check the high-voltage wires and the ignition module, replace them with known good ones |
Replace faulty ignition coil[K] / ignition module[B], damaged high voltage wires. Heavy Duty (salt on the roads, frost alternating with thaws) it is advisable to replace the wires every 3-5 years.
[K] Clean the distributor cover and rotor from dirt and moisture, blown rotor resistor, broken rotor, cover - replace |
Claps in the intake manifold after the engine is running at power levels |
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Candles with the wrong glow rating are used | - | Use spark plugs recommended by the manufacturer |
Increased fuel consumption |
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Leakage of the power system | Smell of gasoline | Tighten hose clamps, threaded connections. Check fit of fittings; if the fit is loose, replace the relevant components |
[K] Too rich mixture due to gasoline leaking into the engine crankcase through a torn fuel pump diaphragm | The oil on the dipstick smells like gasoline, the low oil pressure lamp may light up at low engine speeds | Replace the fuel pump, its diaphragms; if there is a lot of gasoline in the oil, then the oil |
Increased resistance to vehicle movement | Warm car run (after running at least 20 km) from a speed of 50 km / h must be at least 500 m | Check and adjust tire pressure, front wheel alignment, brake system |
[K] Faulty or misadjusted starting device or its drive | See Carburetor engine power system | Adjust trigger (see Carburetor engine power system), replace worn parts |
[K] Excessive fuel level in the carburetor float chamber | There is a strong smell of gasoline from the exhaust pipe, a cold engine starts better than a hot one.
Remove the top cover of the carburetor, check the tightness of the float, its ease of movement and the absence of touching the walls of the float chamber. Checking the tightness of the needle valve: turn the carburetor cap upside down and pump gasoline with the fuel pump lever. The slightest leak of gasoline from under the needle or valve base is unacceptable |
Replace needle valve, adjust float chamber fuel level (see Carburetor engine power system) |
[K] Clogged jets and carburetor passages. Loosely wrapped jets, solenoid valve.
Leaky accelerator pump check valve |
Inspect, blow channels and jets | Rinse with gasoline or acetone and blow through the jets, if heavily soiled, clean them with a fishing line or softwood needle. Screw jets tightly (do not damage the thread and jet!). Replace damaged parts |
[K] Incorrect ignition timing | See General information, Ignition system | Adjust ignition timing |
[K] Faulty switch | Substitute a known-good switch | Replace defective switch |
[K] Weakening or breakage of the springs of the weights of the centrifugal automatic distributor of the ignition, damper rings of the weights are lost, sticking of the weights | Visually and on a special stand | Replace ignition distributor |
[K] Fuzzy operation of the vacuum ignition advance machine: when the vacuum is removed, the plate does not return to its original position | Inspection. The characteristic of the vacuum regulator is taken on a special stand | Eliminate jamming, replace faulty vacuum machine or ignition distributor assembly |
Defective spark plugs: leakage current through cracks in the insulator or carbon deposits on the thermal cone, poor contact in the center electrode assembly | A faulty candle, as a rule, can be identified by the color of soot on the insulator. The absence of external damage and sparking between the electrodes on an inverted candle does not allow us to conclude that it is working | Replace defective spark plugs |
[K] Engine idle control out of order | See Carburetor engine power system | Adjust idle (see Carburetor engine power system) |
Throttle actuator malfunction [K], throttle [V] | Check pedal travel «gas», play in the drive, make sure there is no sticking in the drive | Replace defective parts, lubricate seizing drive parts with engine oil |
[B] Faulty idle speed controller or circuit | The lamp may be on. Substitute a known-good regulator | Replace defective regulator |
Throttle valve of the second chamber of the carburetor [K] / throttle valve [B] does not fully close | The gap between the throttle valve and the walls of the mixing chamber [K] / throttle assembly [B] is visible through the light | [K] Turn the damper stop screw until it closes completely. In this case, the damper should open easily, without jamming. At the end of the adjustment, fill the screw with paint
[B] Check throttle actuator clearance, adjust if necessary. Throttle valve adjustment is not recommended at home |
[K] Carburetor dampers are mounted on axes with a misalignment and do not close at any position of the stop screws | Inspection | Contact a service station or replace the carburetor |
Foreign objects getting under the throttle valve | Inspection | Remove foreign object, check damper operation |
[B] Increased pressure in the fuel lines due to a malfunction of the pressure regulator or its pneumatic line, deformation of the tubes, kink in the drain hose | Inspection, checking the pressure gauge in the fuel rail (no more than 3.2 kgf/cm2 at idle and 4 kgf/cm2 at medium speed) | Replace the defective regulator, tubes, eliminate the kink in the hose, restore the integrity of the pneumatic line |
[B] Nozzle leaks (overflow) | Check injectors (see Injection engine power system) | Replace faulty injectors |
[B] Faulty injection coolant temperature sensor or circuit | Check the resistance of the sensor with an ohmmeter at different temperatures (see Injection engine control system). In the event of an open in the circuit or sensor, the lamp lights up and the cooling system electric fan runs continuously | Restore contact in electrical circuits, replace the faulty sensor |
[B] Defective throttle position sensors, mass air flow sensors or their circuits | In the event of a break in the sensors or their circuits, the lamp lights up. In the event of a break in the throttle position sensor, the engine idle speed does not drop below 1200 min-1, with a break in the mass air flow sensor - below 2000 min-1, however, this almost does not affect the driving performance of the car. If both sensors fail, despite the high idle speed, the car is only barely able to move on its own | Restore contact in electrical circuits, replace the faulty sensor (sensors) |
[B] Oxygen sensor defective: sensitive element poisoned or destroyed, air suction hole clogged, heating coil burnt out, electrical circuits faulty | The lamp is on. You can roughly evaluate the operation of the sensor with an autotester: integrity heating coils are checked with an ohmmeter, output voltage - with a voltmeter (connect the voltmeter without breaking the circuit, for example, by piercing the wires fine needles). see also Injection engine control system. Check if the air intake hole is blocked (anticorrosive, dirt, etc.) | Repair damaged electrical circuits, clean the air intake hole.
Replace defective sensor |
[B] Exhaust leak (area to the oxygen sensor) | The lamp may be on. Inspection at medium engine speeds | Replace defective manifold gasket, tighten seals |
[B] Faulty engine control unit or its circuits | Check if 12V is being supplied to the control unit (see Connection diagram of the VAZ-21214 engine management system with multiport fuel injection for Euro-2 toxicity standards with controller 2123-1411020-10 (type MP 7.0) on cars VAZ-21214), to test the block, replace it with a known-good | Replace failed unit |
Low compression in the engine cylinders (less than 10 kgf/cm2): wear or damage to valves, seats, hydraulic bearings of valve levers [B]; wear, sticking or breakage of piston rings | Using a compression gauge, we measure the compression in the engine cylinders, warmed up to operating temperature, by turning the crankshaft with the starter while the pedal is fully depressed «gas» | Replace rings, pistons.
Repair cylinders . Lap the valves to the seats, if necessary, replace the valves, their guide bushings, grind the seats . |
Increased oil consumption (more than 500 g per 1000 kilometers) |
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Oil leakage through the crankshaft seals, through the gaskets of the oil pan, cylinder head covers, camshaft drive covers, emergency oil pressure sensor, oil filter [IN]. Leak from target hydraulic tensioner line |
Wash the engine, then after a short run inspect for possible leaks | Tighten the fastening elements of the cylinder head, camshaft drive cover, replace worn cuffs, gaskets. Tighten the fittings of the hydraulic tensioner line, replace the damaged tube |
Wear, loss of elasticity of oil seals (valve seals). Wear of valve stems, guide bushings | Parts Inspection | Replace worn parts |
Wear, breakage or coking (loss of mobility) piston rings. Wear of pistons, cylinder liners | Inspection after engine disassembly | Replace rings; clean the grooves in the pistons, replace worn pistons and/or cylinder liners. Boring and honing cylinders |
Clogged crankcase ventilation system | Inspection | Clean the ventilation system |
Detonation (high-pitched metallic knocks, which usually occur when the engine is under load, especially at low speeds - acceleration «tightness «and so on. - and disappearing when the load is reduced) |
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Unacceptably low octane number of gasoline | — | Fill your car with fuel recommended by the manufacturer |
[K] Incorrect ignition timing | See General information, Ignition system | Adjust ignition timing |
Engine overheating | By temperature gauge | Eliminate the cause of overheating (see «The engine gets very hot») |
A lot of carbon deposits in the combustion chamber, on the bottoms of the pistons, valve plates | Inspection after removal of the engine head | Eliminate the cause of soot formation (see «Increased fuel consumption», «Increased oil consumption»). Use oils of the recommended viscosity and, if possible, with a low ash content |
Candles with the wrong glow rating are used | — | Use spark plugs recommended by the manufacturer |
Insufficient oil pressure (control lamp is on) |
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Little oil in the engine | By dipstick oil level | Add oil |
Use of oil of the wrong viscosity | — | Change oil |
Clogging of the oil receiver mesh | Inspection | clear the grid |
Defective oil filter | Substitute a filter with a known good one | Replace filter |
Misalignment, clogging of the pressure reducing valve or weakening of its spring | Inspection | Clean valve. Replace defective valve and/or spring |
Oil pump gear wear | Inspection (see Engine) | Replace worn gears |
Excessive clearance between bearings and crankshaft journals | Determined by measuring parts after disassembling the engine | Replace worn liners. If necessary, replace or repair crankshaft |
[K] Oil dilution due to gasoline leaking into the engine crankcase through a torn fuel pump diaphragm | The oil on the dipstick smells like gasoline, the low oil pressure lamp may light up at low engine speeds | Replace the fuel pump, its diaphragms; if there is a lot of gasoline in the oil, then the oil |
Faulty emergency oil pressure sensor | Checking with a manometer and an ohmmeter (at pressures below 0.5 kgf/cm2 The sensor contact must be connected to «mass», and above 0.8 kgf/cm2 - open) | Replace defective sensor |
The engine gets very hot (the coolant temperature gauge needle is in the red zone) |
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Faulty temperature sensor or gauge | Check the pointer and sensor with an autotester (see electrical equipment) | Faulty sensor, pointer - replace |
Faulty thermostat | See Removing and checking the thermostat In chapter Cooling system | Replace defective thermostat |
Insufficient amount of coolant | The fluid level is below the mark on the expansion tank | Eliminate leaks. Add coolant (see «Coolant level drop in expansion tank») |
Loose or broken water pump belt | The battery charge light may be on | Tighten or replace belt |
A lot of scale in the cooling system | — | Flush the cooling system with a descaling agent. Do not use hard water in the cooling system. Dilute concentrated antifreeze only with distilled water |
Radiator cells dirty | Inspection | Flush the radiator with a high pressure water jet |
Faulty coolant pump | Remove and inspect pump cover (see Cooling system) | Replace cap or pump assembly |
[B] Electric fan does not turn on (s) cooling systems | If one fan does not turn on, its electric motor is faulty or disconnected power cord. Engine performance can be checked by applying 12V directly to its pin. If both do not work, check if 12 V to the control contact of the electric fan relay and to terminal 46 control unit. If yes, then the relay, electrical circuits, or both are faulty electric motor, otherwise - injection control unit or temperature sensor (see Injection engine control system) | Restore contact in electrical circuits. Faulty relays, electric motor, control unit, temperature sensor - replace |
Unacceptably low octane number of gasoline | — | Fill your car with fuel recommended by the manufacturer |
A lot of carbon deposits in the combustion chamber, on the bottoms of the pistons, valve plates | Inspection after removal of the engine head | Eliminate the cause of soot formation. Cm. «Increased fuel consumption», «Increased oil consumption». Use oils of the recommended viscosity and, if possible, with a low ash content |
[K] Incorrect ignition timing | See General information, Ignition system | Adjust ignition timing |
[K] Faulty switch | Substitute a known-good switch | Replace defective switch |
[B] Engine cooling fans constantly running (even on a cold engine) |
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Open in the injection coolant temperature sensor or its circuits | The lamp is on. The sensor and circuits are checked with an ohmmeter (see Injection engine control system) | Replace defective sensor |
The contacts of the relay for turning on the electric fans do not open | Check by tester | Replace defective relay |
Faulty injection system control unit or its circuit | Check the unit at a service station or replace with a known good one | Replace failed unit |
The engine takes a long time to warm up to operating temperature |
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Faulty thermostat | See Removing and checking the thermostat | Replace defective thermostat |
Low air temperature (below - 15°С) | – | Insulate the engine: install thermal and sound insulation of the hood, shields in front of the radiator (do not block the entire area of the radiator in the area of the fan impeller!) |
Coolant level drop in expansion tank |
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Damage to the radiator, hoses, loosening of their fit on the nozzles. Fluid leaking from heater tap | Inspection. Sealing of radiators (engine and heater) tested in a hot water bath with compressed air at a pressure of 1 kgf/cm2 | Replace damaged parts. Tighten hose clamps |
Fluid leakage through the coolant pump seal | Inspection | Replace pump assembly |
Cylinder head gasket damaged. Block or cylinder head defect | When changing the oil, an emulsion with a whitish tint is poured out of the crankcase. There may be copious white smoke from the muffler and oil stains on the fluid surface (in the expansion tank). Coolant leaks on the outer surface of the engine | Replace damaged parts. Do not use water in the cooling system, fill in coolant suitable for climatic conditions |
Extraneous noises and knocks in the engine |
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[K] Increased clearances in the valve mechanism | The sound of valves is heard in the area of the cylinder head cover. | Adjust gaps |
[B] Valve lever hydraulic bearings are inoperative: clearance between cam and lever is too large | The sound of valves is heard in the area of the cylinder head cover. It is possible to finally judge the malfunction of the hydraulic support only after it has been checked | Blow out the oil supply channels to the hydraulic bearings, if necessary, replace the lever bearings |
Sediment or broken valve springs | Inspect the springs, measure their length in a free state and under load | Replace weak or broken springs |
The timing chain has stretched out. Faulty chain tensioner | Inspection | Replace chain, tensioner |
Knock crankshaft and camshaft, connecting rod bearings, pistons, piston pins, play or seizing in the bearings of the coolant pump | Service station check | Repair of parts at the service station or replacement |
Strong engine vibration |
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Irregularity of compression on cylinders more than 2 kgf/cm2: wear or damage to valves, seats, hydraulic bearings of valve levers [B]; wear, sticking or breakage of piston rings | Using a compression gauge, we measure the compression in the engine cylinders, warmed up to operating temperature, by turning the crankshaft with the starter while the pedal is fully depressed «gas» | Replace rings, pistons. Repair cylinders . Lap the valves to the seats, if necessary, replace the valves, their guide bushings, grind the seats . [C] Replace hydraulic bearings if necessary |
Damage to the insulation of high-voltage devices and circuits - interruptions in sparking | [K] Having securely fastened the end of the high-voltage wire at a distance of 8-10 mm from «masses» car, crank the engine with a starter (do not touch high voltage circuits!). between wire and «weight» should spark regularly (Use only known-good high-voltage wires for testing). If there is no spark at the output of the ignition coil, the coil is faulty, if at the output / outputs of the ignition distributor, the rotor or distributor cap is faulty. The breakdown of the rotor or cover is determined by burnouts or cracks on their surface. Health of the rotor resistor (1 kOhm) checked with an ohmmeter.
[B] lamp may light up (incorrect oxygen sensor signal). To check the high-voltage wires and the ignition module, replace them with known good ones |
Replace faulty ignition coil[K] / ignition module[B], damaged high voltage wires. Heavy Duty (salt on the roads, frost alternating with thaws) it is advisable to replace the wires every 3-5 years.
[K] Clean the distributor cover and rotor from dirt and moisture, blown rotor resistor, broken rotor, cover - replace |
The high voltage wires are connected to the distributor[K] / ignition module [B] in the wrong order; disconnected wire | Inspection | Connect the wires according to the firing order of the cylinders |
Defective candles | A faulty candle, as a rule, can be identified by the color of soot on the insulator. The absence of external damage and sparking between the electrodes on an inverted candle does not allow us to conclude that it is working | Replace defective spark plugs |
The gap between the electrodes of the candles does not correspond to the norm | Gap 0.7-0.8 mm [K] or 1.0-1.1 mm [B] is checked with a round feeler gauge | By bending the side electrode, set the desired gap or replace the candles |
Strong soot on the electrodes of the spark plugs; ingress of soot particles into the gap between the electrodes | Inspection. By soot, you can, as a rule, determine the performance of the candle and the condition of the engine | Clean spark plugs with compressed air or mechanically (do not damage the insulator!). Identify and eliminate the cause of increased carbon formation in the combustion chamber, replace the spark plugs if necessary |
[K] Incorrect ignition timing | See Ignition system | Adjust ignition timing |
[K] Faulty switch [K] Weakening or breakage of the springs of the weights of the centrifugal automatic distributor of the ignition |
Substitute a known-good switch Visually and on a special stand |
Replace defective switch Replace ignition distributor |
[K] Clogged jets and carburetor passages. Loosely wrapped jets and solenoid valve | Determined by inspection, purge of channels and jets (see Carburetor engine power system) | Blow out the jets, if heavily soiled, clean them with a fishing line or a needle made of soft wood. Clean the crankcase ventilation system. Screw jets tightly (do not damage the thread and jet!) |
[K] Engine idle control out of order | See Carburetor engine power system | Adjust idle (see Carburetor engine power system) |
[K] Intake of foreign air into the intake manifold | Inspect the joints, check the fit of the hoses, fittings, tightness of the clamps. At the time of starting, turn off the vacuum brake booster by pinching the corresponding hose | Torn gaskets, parts with deformed flanges, defective vacuum booster Replace |
[K] Excessive fuel level in the carburetor float chamber | There is a strong smell of gasoline from the exhaust pipe, a cold engine starts better than a hot one. Remove the top cover of the carburetor, check the tightness of the float, its ease of movement and the absence of touching the walls of the float chamber. Checking the tightness of the needle valve: turn the carburetor cap upside down and pump gasoline with the fuel pump lever. The slightest leak of gasoline from under the needle or valve base is unacceptable | Replace leaky needle valve, adjust float chamber fuel level (see Carburetor engine power system) |
[K] Insufficient fuel level in the carburetor float chamber | See Carburetor engine power system | Adjust fuel level (see Carburetor engine power system) |
[K] Too rich mixture due to gasoline leaking into the crankcase through a torn fuel pump diaphragm | The oil on the dipstick smells like gasoline, the low oil pressure lamp may light up at low engine speeds | Replace the fuel pump with its diaphragm; if there is a lot of gasoline in the oil, then the oil |
[B] Open or short in injector coils or circuits | Check the injector windings and their circuits with an ohmmeter | Replace faulty injectors, ensure contact in electrical circuits |
[B] Nozzles leaking (overflow) or their nozzles are dirty | Check the tightness and shape of the nozzle spray pattern (see Injection engine power system) | Dirty nozzles can be washed on a special bench . Replace leaky or heavily soiled injectors |
[B] Faulty idle speed controller or circuit | The lamp may be on. Substitute a known-good regulator | Faulty regulator replace |
Weakened fastening of the supports of the power unit | Inspection | Tighten fasteners |
Lost elasticity or collapsed power unit supports | Inspection | Replace supports |
Increased content of harmful substances in exhaust gases |
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[K] Excessive fuel level in the carburetor float chamber | There is a strong smell of gasoline from the exhaust pipe, a cold engine starts better than a hot one. Remove the top cover of the carburetor, check the tightness of the float, its ease of movement and the absence of touching the walls of the float chamber. Checking the tightness of the needle valve: turn the carburetor cap upside down and pump gasoline with the fuel pump lever. The slightest leak of gasoline from under the needle or valve base is unacceptable |
Replace leaky needle valve, adjust float chamber fuel level (see Carburetor engine power system) |
[K] Too rich mixture due to gasoline leaking into the crankcase through a torn fuel pump diaphragm | The oil on the dipstick smells like gasoline, the low oil pressure lamp may light up at low engine speeds | Replace the fuel pump, its diaphragms; if there is a lot of gasoline in the oil, then the oil |
[K] Faulty or misadjusted starting device or its drive | See Carburetor engine power system | Adjust trigger (see Carburetor engine power system), replace worn parts |
[K] Engine idle control out of order | See Carburetor engine power system | Adjust idle (see Carburetor engine power system) |
[K] Clogged jets and carburetor passages. Loosely wrapped jets, solenoid valve. Leaky accelerator pump check valve | Inspect, blow channels and jets | Rinse with gasoline or acetone and blow through the jets, if heavily soiled, clean them with a fishing line or softwood needle. Screw jets tightly (do not damage the thread and jet!) |
[B] Nozzles leaking (overflow) or their nozzles are dirty | Check the tightness and shape of the nozzle spray pattern (see Injection engine power system) | Dirty nozzles can be washed on a special bench . Replace leaky or heavily soiled injectors |
[K] Weakening or breakage of the springs of the weights of the centrifugal automatic distributor of the ignition, damper rings of the weights are lost, sticking of the weights | Visually and on a special stand | Replace ignition distributor |
[K] Fuzzy operation of the vacuum ignition timing machine; when the vacuum is removed, the plate does not return to its original position, large play in the bearing | Inspection. The characteristic of the vacuum regulator is taken on a special stand | Eliminate jamming, replace faulty vacuum machine or ignition distributor assembly |
[K] Incorrect ignition timing | See Ignition system | Adjust ignition timing |
[K] Faulty switch | Substitute a known-good switch | Replace defective switch |
Damage to the insulation of high-voltage devices and circuits - interruptions in sparking | [K] Having securely fastened the end of the high-voltage wire at a distance of 8-10 mm from «masses» car, crank the engine with a starter (do not touch high voltage circuits!). between wire and «weight» should spark regularly (Use only known-good high-voltage wires for testing). If there is no spark at the output of the ignition coil, the coil is faulty, if at the output / outputs of the ignition distributor, the rotor or distributor cap is faulty. The breakdown of the rotor or cover is determined by burnouts or cracks on their surface. Health of the rotor resistor (1 kOhm) checked with an ohmmeter.
[B] lamp may light up (incorrect oxygen sensor signal). To check the high-voltage wires and the ignition module, replace them with known good ones |
Replace faulty ignition coil[K] / ignition module[B], damaged high voltage wires. Heavy Duty (salt on the roads, frost alternating with thaws) it is advisable to replace the wires every 3-5 years.
[K] Clean the distributor cover and rotor from dirt and moisture, blown rotor resistor, broken rotor, cover - replace |
Defective spark plugs: leakage current through cracks in the insulator or carbon deposits on the thermal cone, poor contact in the center electrode assembly | A faulty candle, as a rule, can be identified by the color of soot on the insulator. The absence of external damage and sparking between the electrodes on an inverted candle does not allow us to conclude that it is working | Replace defective spark plugs |
[B] Faulty injection coolant temperature sensor or circuit | Check the resistance of the sensor with an ohmmeter at different temperatures (see Injection engine control system). In the event of an open in the circuit or sensor, the lamp lights up and the cooling system electric fan runs continuously | Restore contact in electrical circuits, replace the faulty sensor |
[B] Defective throttle position sensors, mass air flow sensors or their circuits | In the event of a break in the sensors or their circuits, the lamp lights up. In the event of a break in the throttle position sensor, the engine idle speed does not drop below 1200 min-1, with a break in the mass air flow sensor - below 2000 min-1, however, this almost does not affect the driving performance of the car. If both sensors fail, despite the high idle speed, the car is only barely able to move on its own | Restore contact in electrical circuits, replace the faulty sensor (sensors) |
[B] Oxygen sensor defective: sensitive element poisoned or destroyed, air suction hole clogged, heating coil burnt out, electrical circuits faulty | The lamp is on. You can roughly evaluate the operation of the sensor with an autotester: the integrity of the heating coil is checked with an ohmmeter, the output voltage is checked with a voltmeter (connect the voltmeter without breaking the circuit, for example, by piercing the wires with thin needles). see also Injection engine control system. Check if the air intake hole is blocked (anticorrosive, dirt, etc.) | Repair damaged electrical circuits, clean the air intake hole. Replace defective sensor |
[B] Exhaust leak (area to the oxygen sensor) | The lamp may be on. Inspection at medium engine speeds | Replace defective manifold gasket, tighten seals |
[B] Faulty engine control unit or its circuits | Check if 12V is being supplied to the control unit (see diagram in Applications), to test the block, replace it with a known-good | Replace failed unit |
[B] Increased pressure in the fuel lines due to a malfunction of the pressure regulator or its pneumatic line, deformation of the tubes, kink in the drain hose | Inspection, checking the pressure gauge in the fuel rail (no more than 3.2 kgf/cm2 at idle) | Replace the defective regulator, tubes, eliminate the kink in the hose, restore the integrity of the pneumatic line |
Increased resistance to air flow in the intake tract | Check air cleaner element, intake tract (absence of foreign objects, leaves, etc.) | Clean the intake tract, replace the dirty air filter element |
[B] Lamp is on when the engine is running |
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The engine control unit, its circuits, sensors, injectors are faulty. The malfunction may be temporary - then the lamp may turn off by itself, without any intervention | See Injection engine control system, electrical circuit in Applications, previous sections «Engine troubleshooting». Full diagnostics of the injection system is carried out at the service station using specialized equipment | When most sensors fail (except crankshaft position sensor) you can drive to the place of repair on your own. Faulty unit, sensors, injectors, wires - replace |
disconnected (maybe to check) separate sensors, injectors, after which the ignition was turned on (start the engine). At the same time, the corresponding fault code is recorded in the computer's memory, which is not erased even after the electrical connections are restored | — |
Remove for at least 10 seconds «negative» terminal from the battery or remove the fuse of the non-switchable power supply of the injection system (if available). In this case, all fault codes are erased from the computer's memory. After that, when the ignition is turned on for the first time, the lamp will light up, but then go out |