Possible engine malfunctions, their causes and remedies
Cause of malfunction |
Remedy |
Engine won't start |
|
No pressure in the fuel rail: |
Do the following: |
clogged fuel lines |
flush and blow out the fuel tank and fuel lines |
fuel pump faulty |
replace pump |
clogged fuel filter |
change the filter |
faulty fuel pressure regulator |
check the regulator, replace the faulty one |
Faulty ignition system |
|
Engine runs erratically or stalls while driving |
|
Insufficient fuel pressure in the engine fuel line (ramp) |
Cm. «Engine won't start» |
Faulty idle speed controller |
Replace idle speed control |
Air leakage through the crankcase ventilation hoses and the hose connecting the intake manifold to the vacuum brake booster |
Tighten the fastening clamps, replace damaged hoses |
Violated gaps between the pushers and camshaft cams |
|
Faulty ignition system |
See section «Engine management system» |
The engine does not develop full power and is not throttled enough |
|
Incomplete throttle opening |
|
Faulty throttle position sensor |
Replace sensor |
Insufficient fuel pressure in the engine fuel line (ramp) |
See fault «Engine won't start» |
Air filter dirty |
Replace filter element |
Faulty ignition system |
See section «Engine management system» |
Violated gaps between the pushers and camshaft cams |
Adjust valve clearances |
Insufficient compression - below 1 MPa (10 kgf/cm2): |
Do the following: |
broken or stuck piston rings |
parts replace |
poor fit of valves to the seats |
replace damaged valves, grind seats |
Excessive wear of cylinders and piston rings Clean the rings and grooves of the pistons from deposits damaged |
replace pistons, bore and honing cylinder block cylinders |
Increased fuel consumption |
|
Increased resistance to vehicle movement |
Check and adjust tire pressure, brake system, steering wheel alignment |
Faulty ignition system |
See section «Engine management system» |
Faulty injectors. Fuel leakage at connections |
Cm. «Supply system». Tighten pipe connections |
Use of low quality fuel |
Fill with recommended fuel |
Knocking crankshaft bearings |
|
Usually a dull tone, metallic. It is detected when the throttle valves are suddenly opened at idle. Its frequency increases with an increase in the frequency of rotation of the crankshaft. Excessive axial clearance of the crankshaft causes a sharper knock with uneven intervals, especially noticeable with a smooth increase and decrease in the crankshaft speed |
|
Too early ignition |
Adjust ignition timing |
Insufficient oil pressure |
See fault «Insufficient oil pressure at idle» |
Loose flywheel bolts |
Tighten the bolts to the recommended torque |
Increased clearance between journals and main bearing shells |
Sand the necks and replace the liners |
Increased clearance between thrust washers and crankshaft |
Replace the thrust half rings with new ones or with increased thickness, check the gap |
Knocking rod bearings |
|
Usually the knock of the connecting rod bearings is sharper than the knock of the main bearings. It is heard at idle speed of the engine with a sharp opening of the throttle valves. The place of knocking is easy to determine by turning off the spark plugs one by one |
|
Insufficient oil pressure |
see fault «Insufficient oil pressure at idle» |
Excessive clearance between crankshaft journals and bearings |
Replace bushings and grind necks |
The knock of pistons |
|
The knock is usually unvoiced, muffled; called «beating» piston in the cylinder. It is best heard at low engine speeds and under load |
|
Increased clearance between pistons and cylinders |
Replace pistons, bore and honing cylinders |
Excessive clearance between piston rings and piston grooves |
Replace rings or pistons with rings |
Knocking inlet and outlet valves |
|
Increased clearances in the valve train cause a characteristic knock, usually at regular intervals; its frequency is less than the frequency of any other knock in the engine, since the valves are driven by a camshaft, the rotational speed of which is half the speed of the crankshaft |
|
Increased valve clearances |
Adjust gaps |
Valve spring failure |
Replace spring |
Excessive clearance between valve and guide sleeve |
Replace worn parts |
Camshaft lobes wear |
Replace camshaft and shims |
Insufficient oil pressure at idle with a warm engine |
|
Foreign particles getting under the oil pressure reducing valve |
Clean the valve from foreign particles and burrs, flush the oil pump |
Oil pressure reaction valve sticking |
Replace valve |
Worn oil pump gears |
Repair oil pump |
Excessive clearance between bearings and crankshaft main journals |
Sand the necks and replace the liners |
Excessive clearance between journals and camshaft bearing housings |
Replace camshaft or cylinder head with bearing housings |
The use of engine oil of an inappropriate brand and quality |
|
Excessive oil pressure on a warm engine |
|
Seized oil pressure reducing valve |
Replace valve |
The oil pressure reducing valve spring has a higher stiffness |
Replace spring |
Increased oil consumption |
|
Oil leakage through engine seals |
Tighten fasteners or replace gaskets and seals |
Clogged crankcase ventilation system |
Flush the parts of the crankcase ventilation system |
Worn piston rings or engine cylinders |
Rebore cylinders and replace pistons and rings |
Breakage of piston rings |
Replace rings |
Coking of slots in oil scraper rings or grooves in piston grooves due to the use of non-recommended oil |
Clean slots and grooves from carbon deposits, change engine oil recommended by the manufacturer. |
Worn or damaged valve stem seals |
Replace oil seals |
Increased wear on valve stems or guide bushings |
Replace valves, rebuild cylinder head |
Rapid drop of liquid in the expansion tank |
|
Damaged radiator |
Repair or replace radiator |
Damage to hoses or gaskets in pipe connections, loose clamps |
Replace damaged hoses or gaskets, tighten hose clamps |
Fluid leaking from a faucet or heater radiator |
Replace faucet or radiator |
Fluid leakage through the coolant pump seal |
Replace seal |
Damaged cylinder head gasket |
Replace gasket |
Liquid leakage through microcracks in the block or in the cylinder head |
Check the tightness of the block and cylinder head, if cracks are found, replace damaged parts |
Fluid leakage through microcracks in the coolant pump housing, in the outlet pipe of the cooling jacket, in the thermostat, expansion tank or inlet pipe |
Check the tightness, if cracks are found, replace the damaged parts; an insignificant leak can be eliminated by adding a sealant type NIISS-1 to the coolant |
Deformation of the flange of the supply pipe of the coolant pump |
Replace supply pipe |
Low pressure expansion bottle valve opening |
Check plug and replace if necessary |