Engine won't start when cold
The starter turns the crankshaft, but the engine does not start.
Causes of malfunction and solutions:
- no fuel is being supplied to the carburetor. It is necessary to disconnect the hose from the injection pipe of the fuel pump and check the fuel supply with the manual priming lever. If fuel is not supplied, disconnect the hose from the suction pipe and check whether a vacuum is created at the inlet of this pipe. If there is no vacuum, then check the fuel pump by removing the cover and the upper pump housing, flushing the fuel filter and making sure the diaphragms are intact. If there is a vacuum at the inlet of the suction pipe, then the cause of the malfunction should be sought in the fuel lines, fuel tank or fuel fine filter. It is necessary to blow out the fuel lines with a tire inflation pump. At the same time, gurgling sounds should be heard in the fuel tank. The fine filter may be clogged. It is necessary to remove it from the hoses, connect the hoses and start the engine. Check for changes in engine operation with the filter removed. If necessary, replace the filter with a new one. After removing the fuel tank, wash it with gasoline. To remove the tank, disconnect «mass» battery cable, raise the rear seat cushion and remove the hatch cover located on the floor under the carpet. Disconnect electrical wires and hoses from sensor 9 (see fig. 39) fuel level. Remove as much fuel as possible from the tank. Loosen the clamps 17 of the fuel tank, disconnect the hoses 15 and 13 and remove the tank. Drain the remaining fuel from the tank. Install the tank in reverse order;
- the solenoid shut-off valve of the carburetor does not open when the ignition is turned on due to a break in the wires going to the valve control unit and to the valve, as well as due to malfunctions of the valve control unit or the valve itself. It is necessary to check the condition of the wires and their connections. Replace damaged wires. In case of malfunctions of the solenoid valve or control unit, replace them with new ones;
- the ignition system does not work. The procedure for checking and troubleshooting is described in the chapter «Ignition system»;
- the air damper does not open at the first flashes in the cylinders. Turning the crankshaft with a starter, check whether the choke lever is turned by the carburetor starter rod at the first flashes in the cylinders. If not, you need to disassemble the starting device and check the tightness of its diaphragm, eliminate the jamming of the rod;
- air damper does not close. Check the air damper drive, adjust the length of the rod so that when the handle is pulled out, the air damper is completely closed.
Engine runs erratically or stalls at idle
The malfunction is determined by the uneven sound of the exhaust and sudden stops of the engine at idle.
Causes of the malfunction and how to fix it:
- the ignition system is not working satisfactorily. The procedure for checking and troubleshooting is described in the chapter «Ignition system»;
- the adjustment of the carburetor idle system is violated. Adjust the idle speed of the engine;
- malfunctions in the carburetor forced idle economizer system. Check the operation of the forced idle economizer;
- the jets and channels of the carburetor idle system are clogged. Disassemble the carburetor, rinse with gasoline and blow through the channels and jets with compressed air;
- water entering the carburetor. Remove water from the carburetor and fuel tank;
- air leakage through the damaged diaphragm of the starting device. Replace diaphragm;
- air leakage through a hose going to a vacuum brake booster, or through a hose to a vacuum ignition timing controller. Check the hoses and the reliability of their attachment to the nozzles, tighten the clamps if necessary. If the hose is damaged, its leakage can be temporarily eliminated with an adhesive mite and the hose should be replaced as soon as possible;
- air leakage through gaskets in the intake manifold connections to the carburetor or cylinder head. Tighten the carburetor nuts (only on a cold engine) and inlet pipeline. If necessary, replace gaskets;
- air leakage through a damaged vacuum sampling tube to the econometer. Replace damaged tube.
The engine runs unevenly and unstably at a high crankshaft speed
Causes of the malfunction and how to fix it:
- malfunctions in the ignition system. Check and repair as indicated in chapter «Ignition system»;
- the jets of the main dosing system of the carburetor are clogged. Disassemble the carburetor, wash it with gasoline and blow its jets and channels with compressed air.
The engine does not develop full power and does not have sufficient throttle response
Causes of the malfunction and how to fix it:
- incomplete opening of the throttle valves of the carburetor. Adjust the throttle actuator;
- air filter contamination. Replace the filter element;
- faulty ignition system. Check and repair as indicated in chapter «Ignition system»;
- fuel pump defective. Check the operation of the pump, if necessary, replace damaged parts;
- accelerator pump not working. Check the performance of the accelerator pump and the condition of the pump parts, if necessary, replace damaged parts;
- clogged main fuel jets. Disassemble the carburetor, wash in gasoline and blow with compressed air;
- air damper not fully open. Check and adjust the carburetor air damper drive;
- the fuel level in the carburetor float chamber is not correct. Remove the carburetor and adjust the fuel level in the float chamber;
- the tightness of the diaphragm of the economizer of power modes is broken. Remove the diaphragm, check its condition, replace the diaphragm if damaged;
- detonation in the engine cylinders due to the formation of a significant layer of soot on the piston crown and the walls of the combustion chamber. It is recommended to contact a service station to remove the engine cylinder head and clean the combustion chambers, pistons and valves from carbon deposits;
- clogging of the tube or check valve of the gasoline vapor separator. Blow out the tube with the valve with compressed air;
- gaps in the valve mechanism are violated. Check and repair as indicated in chapter «Gas distribution mechanism»;
- insufficient compression in the engine cylinders. Check and repair as indicated in chapter «crank mechanism».
Interruptions in the operation of the engine in all modes
Reasons and ways to eliminate them:
- faulty ignition system. The method of verification and elimination is described in the chapter «Ignition system»;
- presence of water at the bottom of the fuel tank. Remove sediment from the fuel tank. If necessary, remove the tank and rinse with gasoline;
- clogged fuel lines or filters in the carburetor, fuel pump or fine fuel filter. Blow out the fuel lines with a tire inflation pump, remove the filters and rinse in gasoline;
- jets and carburetor channels are clogged. Disassemble the carburetor and wash its jets and channels with gasoline, blow with compressed air;
- increased or decreased fuel level in the carburetor float chamber. With an increased fuel level in the carburetor, the combustible mixture is re-enriched, which is characterized by black exhaust, «shots» in the muffler. At a lower level, the mixture becomes leaner, which is manifested by pops in the intake manifold. Disassemble the carburetor and adjust the fuel level in the float chamber;
- the adjustment of the gaps in the gas distribution mechanism is violated. Check and adjust gaps (see chapter «Gas distribution mechanism»).
Increased fuel consumption
Fuel consumption largely depends on the driving style, time of year, vehicle operating conditions (driving in the city, on highways for long distances or on country roads). Therefore, it is difficult to name a specific figure for fuel consumption. Normal fuel consumption per 100 km of track, measured using a special technique, with a four-speed gearbox (five-speed) should be no more than 8.6 liters during operation in the city (8.6 l), on the highway at a speed of 90 km / h 6.1 l (5.7 l) and at a speed of 120 km / h consumption of 8.2 liters (7.8 l).
However, if, under the same operating conditions of the car, fuel consumption has increased, the causes of the malfunction and the remedies are as follows:
- carburetor choke not fully open. Check and adjust the air damper actuator;
- increased resistance to vehicle movement due to incorrect stud pressure, wheel alignment or incomplete wheel release. Check and adjust tire pressure and wheel alignment. Troubleshoot the brake system as indicated in chapter «Brake system»;
- incorrect ignition timing. Check and adjust the ignition timing;
- high fuel level in the carburetor float chamber. Remove and disassemble the carburetor, check and adjust the installation of the carburetor float;
- the air jets of the main dosing systems of the carburetor are clogged. Disassemble the carburetor, wash the jets and channels with gasoline and blow with compressed air;
- The ignition distributor vacuum regulator does not work. Contact a service station to check the vacuum regulator on the stand and adjust or replace it;
- the tightness of the diaphragm of the economizer of the power modes of the carburetor is broken. Remove the diaphragm, check its condition, replace with a new one if necessary;
- the spring of the economizer of the power modes of the carburetor has weakened. Replace the spring with a new one;
- the carburetor solenoid shut-off valve does not shut off the fuel supply at forced idle due to the carburetor limit switch not closing, or a break in the wire between the control unit and the carburetor limit switch, or a malfunction of the electronic control unit. Clean the contact surfaces of the switch, check the condition of the wires. Replace the defective control unit with a new one;
- insufficient compression in the engine cylinders. Eliminate as directed in chapter «crank mechanism».