Possible malfunctions of the ZMZ-402 and ZMZ-4021 engines of the GAZ-3110 car

If you think that the engine sounds that were not there before, immediately check if everything is in order with the engine

Most often, engine knocks are associated with serious malfunctions, for diagnosing and eliminating which you will have to disassemble the engine in a service or garage.

You can try to determine the cause of the knocks yourself in order to decide whether to go to the car service on your own or in tow.

Cause of malfunction (Remedy)

Engine won't start

Lean mixture (pops in carburetor):

- the mesh filter of the carburetor, fuel pump or fine fuel filter is clogged

Wash the filter in unleaded petrol and blow it out with compressed air

- the diaphragm is torn or the tightness of the fuel pump valves is broken

Replace diaphragm or valves

- water in the sump or fuel line has frozen

Heat the sump or fuel line with hot water

- clogged fuel line

Blow out the fuel lines

- the carburetor air damper does not close completely;

Adjust air damper actuator

- clogged jet: main fuel and idle;

Wash in unleaded gasoline and blow jets with compressed air

- the fastening of the carburetor to the intake pipe or the intake pipe to the cylinder head has loosened;

Tighten fasteners, replace gaskets if necessary

- low fuel level in the carburetor float chamber

Adjust fuel level

- the EGR valve sticks in the open position

Replace recirculation valve

Rich combustible mixture (pops in the muffler when starting the engine):

- the carburetor air damper does not open completely;

Adjust air damper actuator

- the tightness of the fuel supply valve is broken;

Replace the valve seal

- the tightness of the float is broken;

Repair the float or replace the float

- clogged air jets of dosing systems;

Rinse jets with unleaded petrol and blow with compressed air

- adjustment of the mixture quality screw is broken;

Adjust the desired composition of the mixture

- too high fuel level in the carburetor float chamber

Adjust fuel level

The engine does not start in cold weather:

- The air damper does not close

Adjust air damper actuator

Engine runs erratically at idle

- High or low fuel level in the carburetor float chamber

Adjust fuel level

- Wrong idle speed

Adjust the desired composition of the mixture

- A large amount of water in the sump of the fine fuel filter and the fuel tank

Drain sediment from filter and tank

- Incorrect adjustment of clearances in the valve drive

Adjust valve clearances

- The fastening of the carburetor, intake pipe, gas pipeline has loosened

Tighten fasteners, replace gaskets if necessary

Increased toxicity of exhaust gases

- Rich combustible mixture

See "Engine will not start (Rich mixture)"

- Adjustment of gaps in the valve drive is broken

Adjust valve clearances

The engine does not develop full power and does not have sufficient throttle response:

- Faulty carburetor accelerator pump

Check pump flow, replace damaged parts

- Low fuel level in the carburetor float chamber

Adjust fuel level

- Adjustment of gaps in the valve drive is broken

Adjust valve clearances

- Carburetor throttles do not open fully

Adjust the throttle actuator

- Poor combustible mixture

See "Engine will not start (lean mixture)"

- Clogged air filter element

Replace filter element

- Adjustment of gaps in the valve drive is broken

Adjust valve clearances

- The position of the dampers "Winter-Summer" does not correspond to the season

Set dampers for the season

Increased fuel consumption

- Poor or rich combustible mixture

See "Engine won't start"

- Clogged air filter element

Replace filter element

- Wrong initial ignition timing

Adjust ignition timing

- The vacuum corrector of the ignition distributor is faulty

For change the vacuum corrector or distributor

- The tightness of the power supply system is broken

Restore tightness

- Increased resistance to vehicle movement

Check and adjust the brake system, wheel bearings, tire pressure

Engine overheating

- Faulty thermostat

Replace thermostat

- Weak tension of the fan and water pump drive belts

Adjust belt tension

- Wrong initial ignition timing

Adjust ignition timing

- Poor combustible mixture

See "Engine will not start (lean mixture)"

- Severe contamination of the radiator

Rinse the cooling system, flush the radiator with a jet of water

- Increased resistance to vehicle movement

Check and adjust the brake system, wheel bearings, tire pressure

- Faulty water pump

Replace pump

- The engine continues to run after the ignition is turned off

Motor overheat See "Motor overheat"

- Low octane fuel used

Use fuel with the correct octane rating

Knock knocks in the engine

- Early ignition timing

Adjust ignition timing

- A large layer of soot on the walls of the combustion chambers and piston bottoms

Clean carbon deposits

- Low octane fuel used

Use fuel with the correct octane rating

Insufficient oil pressure on a warm engine

- Faulty or clogged oil pressure reducing valve

Rinse the valve parts and the seat in the oil pump housing, if necessary, replace the spring or valve

- Faulty oil pressure sensor or gauge

Check the pressure with a control pressure gauge, replace the defective device

- Engine overheating

Turn on the oil cooler, eliminate the cause of overheating

- Large wear of the main bearing shells

Replace Earbuds

- Wear of oil pump parts

Replace the gasket between body and cover with a thin paper gasket or replace the pump

Increased oil consumption

- Large wear of piston rings

Replace piston rings

- Clogged crankcase ventilation system

Rinse with unleaded gasoline and blow out with compressed air the hoses and ventilation channels in the intake pipe and the parts of the oil separator in the rocker cover

- Oil leakage through engine seals

Tighten connections, if necessary, replace gaskets or seals

- Large wear or destruction of valve stem seals

Replace caps

Engine knocks

- Wear of the connecting rod and piston group

Repair the engine

- Large gaps between rocker arms and valves

Adjust valve clearances

- Large gaps between valve stems and guide bushings

Replace worn parts or valve head assembly

- Wear of camshaft cams and pushers

Replace worn parts

- Large gap between thrust rings and crankshaft

Replace thrust rings

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