Diagnostics 4 GAZ-3110

Low idle speed:

  • - Incorrect ignition timing (See "GAZ-3110 ignition timing") Adjust the ignition timing
  • - Engine not warmed up (According to the temperature gauge) Warm up the engine to operating temperature
  • - Foreign air is sucked into the intake manifold (Inspect the joints, check the fit of the hoses, fittings, tighten the clamps)

Temporarily disconnect the brake booster by squeezing the corresponding hose (the force on the brake pedal is significantly will increase!)

Replace torn gaskets, parts with deformed flanges, faulty vacuum booster

- Clogged carburetor fuel jets (main fuel and idle). The engine starts only after several vigorous presses on the gas pedal.

A hot engine starts better than a cold one. Inspect, blow out the channels and jets.

Wash with gasoline or acetone and blow out the jets, if heavily contaminated, clean them with a fishing line or a needle made of soft wood (toothpick). Tighten the jets tightly (do not damage the threads and the jet!)

- Insufficient fuel level in the carburetor float chamber / The engine starts poorly and pulls poorly. Possible pops in the carburetor.

When you pull out the "choke" button, the markets and dips decrease or disappear completely. To check the fuel level, lift the carburetor cover. Adjust the fuel level

- The fuel pump does not create the necessary pressure in the system, the engine starts poorly and "pulls" poorly.

Check the pressure at the outlet of the fuel pump (at least 3.5 kgf / cm 2) make sure the mesh filter of the fuel receiver is clean.

Clean the mesh of the fuel receiver. Fuel pump not providing the required pressure in the system — replace

- The fuel pressure regulator is faulty (the drain channel is constantly slightly open) (The engine takes a long time to start)

Connect a pressure gauge to the fuel rail supply hose through a suitable tee — the fuel pressure in the rail should be at least 2.5 kgf/cm 2 at idle.

If this is not the case, pinch the drain hose — the pressure should increase (this indicates that the fuel pump and supply line are in good condition). Replace the faulty regulator

- 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, ease of movement and absence of contact with the walls of the float chamber.

Checking the tightness of the needle valve: remove the carburetor cover and pull the float up with your finger, pump gasoline with the fuel pump lever.

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

- The carburetor fuel jets are not tightly screwed in. The air jets are clogged. There is a strong smell of gasoline coming from the exhaust pipe, the engine starts better when cold than when hot.

The fuel level in the float chamber is normal (to check, lift the carburetor cover)

Wash with gasoline or acetone and blow out the jets, if heavily contaminated, clean them with a fishing line or a needle made of soft wood. Tighten the jets tightly (do not damage the threads and the jet!)

- The idle speed control or its electrical circuits are faulty.

Replace the control with a known good one. Replace the faulty regulator

- Increased air flow resistance in the intake tract.

Check the air filter element, intake tract (absence of foreign objects, leaves, etc.) Clean the intake tract, replace the dirty air filter element

High idle speed:

  • Adjust the idle speed
  • - Long-term driving at high engine speeds. After 30-40 seconds of idling, the speed drops to normal. It is not a malfunction
  • - Malfunction of the accelerator drive.

Check the accelerator pedal travel, the gap in the drive (free pedal travel), make sure that the parts are not jammed, replace defective parts, lubricate the cable with engine oil

- The carburetor starting device or its drive is faulty or not adjusted.

See "ZMZ-402 engine fuel system". Adjust the starting device, replace worn parts

  • - Incorrect ignition timing setting

(See "GAZ-3110 ignition timing")

  • Adjust the ignition timing angle
  • - One (usually TPS) or several sensors of the system are faulty engine control or their circuits. The KMSUD indicator lamp is on.

The diagnostic codes can be used to accurately determine the malfunction.

Check the sensors and their circuits with an autotester. Restore contact in the electrical circuits, replace faulty sensors.

- The fuel pressure regulator is faulty or is not supplied with vacuum from the intake manifold, or the fuel outlet hose (tube) is pinched.

Using a suitable tee, connect a pressure gauge to the fuel rail supply hose - the fuel pressure in the rail should be no more than 3.2 kgf / cm 2 at idle.

If this is not the case, check whether vacuum is supplied from the intake manifold to the regulator. Inspect and blow out fuel lines.

Replace defective regulator, tubes, eliminate hose kinks, restore integrity of air line

- Excessive fuel level in carburetor float chamber. A strong smell of gasoline is felt 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, ease of its movement and the absence of contact with the walls of the float chamber,

Checking the tightness of the needle valve: remove the carburetor cover and pull the float up with your finger, pump gasoline with the fuel pump lever, the slightest leak of gasoline from under the needle or valve seat is unacceptable.

Replace the leaky needle valve, adjust the fuel level in the float chamber

- The idle air jet is clogged (Inspection)

Flush with unleaded gasoline or acetone and blow out the jet.

If heavily contaminated, clean it with a fishing line or a needle made of soft wood (with a toothpick). Flush the crankcase ventilation system

- Over-enriched mixture due to gasoline leaking into the engine crankcase through a torn diaphragm of the fuel pump.

The oil on the dipstick smells of gasoline, the low oil pressure lamp may light up at idle.

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

  • - Leaky injectors (overflow) (Check the injectors) Replace faulty injectors
  • - The throttle valve of the second chamber of the carburetor / throttle valve does not close completely.

When held up to the light, a gap is visible between the throttle valve and the walls of the mixing chamber / throttle assembly.

Use the stop screw of the valve to achieve its complete closure.

In this case, the valve should open easily, without jamming. After adjusting the screw heads, fill them with paint

  • - The carburetor flaps are mounted on the axes with a skew and therefore do not close (Inspection) Replace the carburetor
  • - Foreign objects getting under throttle valve (Inspection) Remove foreign object, check operation of valve
  • - Idle speed control valve or its electrical circuits are faulty

Replace the valve with a known good one. Replace faulty valve

In cold weather, the engine stalls soon after starting to move, but starts up again after a short period of standing:

- Ice plug has formed in the carburetor diffuser (the heated air supply hose is not connected to the outlet manifold)

(Inspection) Secure the hose to the heated air intake pipe with a clamp.

In hot weather, the engine stops spontaneously and starts with difficulty:

- Steam lock in the fuel system. Inspect the fuel lines, blow out the fuel line with a tire pump.

Remove kinks in the hoses, replace deformed tubes