During the operation of the engine, some malfunctions may occur:

  • - engine does not start;
  • - the engine is unstable;
  • - high or low idle speed of the crankshaft;
  • - increased toxicity of exhaust gases.

Let's consider the causes and methods of correcting these defects and some others.

Engine won't start

Fuel supply interrupted - Check fuel pump fuse

Fuel pump does not work - Check the condition of the contacts in the connections of the pump, pump relay and start relay

Valve valve timing - Restore the phases at the service station

The pressure reducing valve of the fuel system is out of order - Replace the valve

Clogged fuel filter - Change filter

Faulty ignition system:

The contact in the circuits of the ignition coils and the control unit is broken - Restore the contact

Ignition coil failed - Replace coil

Engine running erratically

Water in the fuel tank - Drain sediment from the tank

Air leakage through leaks in the intake system, crankcase ventilation or idle speed control - Repair leaks in the connections

Interruptions or failure of one of the cylinders:

  • - carbon deposits on a candle or failure of a candle - Clean carbon deposits or replace a candle
  • - contact of the injector is broken or the injector is out of order - Restore contact or replace the injector
  • - spark plug tip broken - Replace tip
  • - control block is faulty - Replace block

Interruptions or failure of two cylinders:

  • - faulty ignition coil - Replace coil
  • - control block is faulty - Replace block

High idle speed, warm engine

Leaks in the crankcase ventilation and idle air control hose connections - Repair leaks in the connections

The contact of the idle speed regulator is broken or the regulator is out of order - Repair the contact or replace the regulator

The contact of the sensors of the engine management system is broken or the sensors fail - Restore contact or replace the faulty sensors

Exhaust gases toxicity increased

CO adjustment is broken - Adjust the CO content with the adjusting screw on the mass air flow sensor

The tightness of the valves is broken - Grind the valves

Flinger seals worn out - Replace seals

The contact of the coolant temperature sensor is broken or the sensor is out of order - Repair the contact or replace the sensor

Wear of parts of the cylinder-piston group - Repair the engine

The engine does not develop full power

Air filter dirty - Replace filter element

Clogged fuel filter - Change filter

Air throttle not opening fully - Adjust damper actuator

Decrease in fuel pump performance - Replace pump

Engine overheating

The tension of the water pump and generator drive belt is loose - Adjust the belt tension

Thermostat is defective - Replace the thermostat

Insufficient amount of liquid in the engine cooling system - Add coolant

Heavy contamination of the radiator - Rinse the radiator with a jet of water

Fan motor defective - Check fan motor, relay sensor. Replace defective nodes

Water pump defective - Replace pump

Low oil pressure

Faulty or clogged oil pump relief valve - Wash valve parts or replace defective parts

Motor overheating - Eliminate cause of overheating

Worn oil pump parts - Replace pump

Worn main bearing shells - Replace bearing shells

Increased oil consumption

Worn or coked piston rings - Repair the engine

The crankcase ventilation system is broken - Flush the system parts

Flinger seals worn out - Replace seals

Oil leak through gaskets and seals - Eliminate leakage, if necessary, replace gaskets and seals

Engine knock

Hydraulic pusher failed - Replace hydraulic pusher

The hydraulic chain tensioner is out of order - Replace the hydraulic tensioner

The connecting rod and piston group is worn out - Repair the engine

Worn chain tensioner shoe - Replace shoe

Broken valve spring - Replace spring

new

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