The crankshaft is turned by the starter, but the GAZ-3110 engine does not start

Problems with starting a car engine can be divided into two main groups depending on the degree of engine heating

Engine cold

At least 6 hours have passed since the engine was turned off at an outside air temperature of +20 °C and at least 3 hours at –20 °C, the oil temperature in the engine crankcase coincides with the ambient temperature.

The techniques for starting an engine with a fuel injection system are the same at any outside temperature.

Engine is warm or hot

The oil temperature in the engine crankcase is higher than the ambient temperature. To start, just turn on the starter without touching the gas pedal.

The engine control system itself will set the fuel and ignition parameters necessary for starting.

- There is no fuel in the tank according to the indicator and fuel level warning lamp

Pour fuel into the tank

- Battery is low

The voltage at the battery terminals when the consumers are turned off is below 12 V.

After several revolutions, the starter stops cranking the crankshaft and a cracking noise may be heard from under the hood. Charge the battery; if it does not charge, replace it

- Reduced battery capacity

The voltage at the battery terminals when the consumers are turned off is more than 12 V, but when the starter is turned on, it drops to 6 V.

After a few revolutions, the starter stops cranking the crankshaft and a cracking noise may be heard from under the hood.

Make sure there is no short circuit in the starter (see above) Charge the battery with a low current (no more than 1 A); if the capacity is still insufficient, replace the battery

- Oxidation of battery terminals, loose fit

When the starter is turned on, the voltage in the on-board network drops much more than at the battery terminals.

After several revolutions, the starter stops cranking the crankshaft and a cracking noise may be heard from under the hood. Crimp the terminals, clean the contacts, lubricate them with any grease

- Thickened engine oil in winter

Look at the oil on the dipstick. Replace the oil with one that suits the climatic conditions

- Malfunction in the low voltage circuit

Check the circuit from the battery to the ignition coil (via the ignition switch) and then to the switch with an ohmmeter.

Clean oxidized tips, tighten loose wire fastenings, replace damaged wires, ignition switch or its contact part

- Ignition distributor is faulty

Determined by an autotester (see “Ignition system”) or by replacing the sensor with known to be good. Replace the faulty sensor

- The switch-ignition distributor circuit is faulty

Checking with an ohmmeter. Clean oxidized tips, tighten loose wire fastenings, replace damaged wires

- The switch is faulty

Disconnect the wires from the ignition distributor. Secure the tip of the high-voltage wire coming from the ignition coil at a distance of 6-3 mm from ground.

Manually close and open the “+” and “D” contacts of the switch.

At the moment of opening, a spark should jump between the tip of the high-voltage wire and the ground. Replace the faulty switch

- Damage to high-voltage devices and circuits

Having securely secured the end of the high-voltage wire at a distance of 6-3 mm from the vehicle ground, crank the engine with the starter (do not touch the high-voltage circuits!).

A spark should regularly jump between the wire and ground (to check, use only known-good high-voltage wires).

If there is no spark at the terminal of the ignition coil, the coil is faulty; if at the terminal/s of the ignition distributor, the slider or distributor cap is faulty.

Burnouts of the slider or cover are determined visually. The serviceability of the slider resistor and spark plug tip resistors is checked with an ohmmeter.

To check, replace the high-voltage wires and ignition coils with known good ones. Replace the faulty ignition coil/coils. Replace damaged high-voltage wires.

In severe operating conditions, salt on the roads, frosts alternating with thaws, it is advisable to replace the wires after 3-5 years

Clean the distributor cap and slider from dirt and moisture, replace the burnt-out slider resistor, if you suspect an insulation breakdown (burnouts, cracks) of the slider and distributor cap, replace them

- High voltage wires are connected to the distributor / ignition coils in the wrong order

Inspection. Connect the wires according to the firing order of the cylinders

- The gap between the spark plug electrodes is not normal

A gap of 0.7-0.85 mm or 0.8-0.95 mm is checked with a round feeler gauge. By bending the side electrode, set the required gap or replace the spark plugs

- Defective spark plugs

Replace the spark plugs with known good ones or check them on a special stand - (The absence of external damage and sparking between the electrodes on an inverted spark plug does not allow us to draw a conclusion about its operability). Replace faulty spark plugs

- Incorrect ignition timing setting

See "Ignition system". Adjust the ignition timing

Valve distribution phases are disrupted. Check the alignment of the marks on the crankshaft and camshaft. Establish the correct relative position of the shafts (according to the marks)

- There is no power supply to the engine control unit

Check whether +12 V is supplied to pins 1 and 2 of the engine control system harness block, the engine control system relay is activated, whether +12 V is supplied to pin 37 of the control unit when the ignition is turned on, and also - regardless of the position of the ignition switch - to pin 18 of the block (see diagram).

Also check the ground wires with an ohmmeter: contact 12 of the harness block, contacts 2, 14, 19,24 of the control unit. Replace faulty relays, wires, connectors. Strip and crimp the terminals

- The engine control unit, its circuits or sensor are faulty. The KMSUD indicator lamp is on.

By diagnostic codes you can accurately determine the malfunction (see “ZMZ-4062 engine control system")

Check the crankshaft position sensor circuit with an ohmmeter, the resistance of the sensor itself (850-900 Ohms); visually check for mechanical damage to the sensor.

Clean the sensor rod from metal dust, check the gap between it and the crankshaft ring gear (1.0-1.5 mm).

For testing, replace the control unit with a known good one. Replace the faulty unit, sensor, wires

- Fuel filters are clogged, water in the power system is frozen, hoses are pinched, fuel line pipes are deformed

When the engine is cranked with the starter, there is no smell of gasoline from the exhaust pipe. There is no gasoline in the float chamber of carburetor 1 - when you press the “gas” there is no jet of fuel from the accelerator pump nozzle.

The presence of gasoline (under pressure) in fuel rail 1 can be checked by briefly disconnecting the supply hose from the fuel rail (remember that gasoline is a fire hazard!)

In winter, roll the car into a warm garage, blow out (with a tire pump) the power system from the engine to the fuel tank, replace damaged hoses and tubes, clogged filters

- Fuel pump does not work

Remove the fuel supply hose from the carburetor and, holding it with your finger, pump fuel with the pump lever.

A working pump should develop noticeable pressure, which should remain in the hose for at least 10 seconds. Replace the fuel pump or its diaphragm

- Poor contact in the fuel pump power circuit (including the ground wire) or its relay is faulty

Fuse No. 9 in the right fuse box has blown. It is checked with an ohmmeter on de-energized circuits or a voltmeter under voltage.

Inspect fuse No. 9. Clean the contacts, crimp the terminals, replace the faulty relay, wires, blown fuse (first make sure there is no short circuit in the protected circuit)

- The fuel pump does not create the required pressure in the system

Check the pressure at the outlet of the fuel pump (at least 3.5 kgf/cm 2), make sure the fuel inlet strainer is clean.

Clean the fuel inlet grid. Fuel pump that does not provide the required pressure in the system - replace

- The injectors or their circuits are faulty (if one or two injectors are faulty, the engine still starts)

The KMSUD indicator lamp may light up. Using diagnostic codes, you can accurately determine the malfunction (see “Engine control system ZMZ-4062")

Check the injector windings and their circuits with an ohmmeter (no open or short circuit).

Make sure they are working (click when power is applied to the winding). Replace faulty injectors, ensure contact in electrical circuits

- The electromagnetic valve EPHH is faulty or no voltage is supplied to it when the ignition is turned on (the EPHH control unit, its circuits, microswitch are faulty) 

See Engine power supply system ZMZ-402, If the valve itself is faulty aven, then when +12 V is supplied to it from the battery, the engine should start. Replace the faulty valve, EPHH control unit, ensure contact in the electrical circuits

- The carburetor starting device or its drive is faulty or not adjusted. See “ZMZ-402 engine power supply system"

Adjust the starter, replace worn parts

- Suction of foreign air into the intake manifold

Inspect the joints, check the fit of the hoses, fittings, and the tightness of the clamps. Temporarily disconnect the vacuum brake booster by squeezing the corresponding hose (the force on the brake pedal will increase significantly)

Torn gaskets, parts with deformed flanges, faulty vacuum booster, replace

- The main fuel and idle jets of the carburetor are clogged.

The engine starts only after several vigorous presses on the gas pedal. A hot engine starts better than a cold one.

Inspect and blow out the channels and jets.

Rinse with gasoline or acetone and blow out the jets; if they are heavily soiled, clean them with a fishing line or a soft wood needle (toothpick).

Tighten the jets tightly (do not damage the threads and the jet)

- The carburetor fuel jets are not tightly screwed on. Air jets clogged 

There is a strong smell of gasoline coming from the exhaust pipe; a cold engine starts better than a hot one. The fuel level in the float chamber is normal (to check, lift the carburetor cover).

Rinse with gasoline or acetone and blow out the jets; if they are heavily soiled, clean them with a fishing line or a soft wood needle (toothpick). Screw the jets tightly (do not damage the threads and the jet!)

- Excessive fuel level in the carburetor float chamber

There is a strong smell of gasoline coming 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, the ease of its movement and the absence of touching the walls of the float chamber.

Checking the tightness of the needle valve: by removing the carburetor cover and pulling the float up with your finger, pump up gasoline using the fuel pump lever.

The slightest leak of gasoline from under the needle or valve seat is unacceptable. Replace the needle valve, adjust the fuel level in the float chamber

- Over-enriched 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 light may come on when the engine is idling.

Replace the fuel pump or its diaphragm; if there is a lot of gasoline in the engine oil, then so does the oil

- Exhaust gas recirculation valve stuck open

Try moving the valve stem to close it.

At medium engine speeds, the rod should move (in this case, the valve opens due to vacuum in the supply hose), at idle speed and at full load - no.

Check the operation of the thermal valve on the cylinder head:

- it must open at temperatures above 40°C. The faulty valve will be replaced

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The lubrication system diagram is shown in Fig. 1. Oil pressure in the lubrication system of a warm engine at low crankshaft speed 550–650 min -1

In the article we will consider possible malfunctions of the front axle of the UAZ-3151