Engine malfunctions

If the engine does not start, there are three main reasons:

  • —launch system not working;
  • - the ignition system does not work;
  • —The power system is not working.

If, for any reason, the spark plugs are flooded during an unsuccessful start attempt, use the cylinder purge mode.

To do this, press the gas pedal all the way and turn on the starter.

In this mode, there is no fuel supply and gasoline is removed from the cylinders by air flow, while the spark plugs are dried. After purging, try to start again in normal mode.

Fault (Cause / Remedy)

The engine does not develop full power and does not have sufficient throttle response. Jerks and dips when driving a car:

  • - There is little fuel in the tank (According to the indicator and fuel level indicator lamp / add fuel)
  • - the fuel pump does not create the necessary pressure in the system (Remove the fuel supply hose from the carburetor and, holding it with your finger, pump fuel with the pump lever) A serviceable pump should develop a noticeable pressure that should be kept in the hose for at least 10 s / Replace the fuel pump or its aperture
  • - the fuel pump does not create the necessary pressure in the system (Check with a pressure gauge the pressure at the outlet of the fuel pump when the ignition is turned on (at least 3.5 kgf / cm2), make sure that the fuel inlet strainer is clean. / Clean the fuel inlet grid. fuel pump, not providing the desired pressure in the system, replace
  • - Poor contact in the fuel pump power circuit (including ground wires) or its relay is faulty (Checked with an ohmmeter when the circuits are de-energized or with a voltmeter under voltage) / Clean the contacts, crimp the terminals, replace the faulty relay, wires
  • - Poor contact in the power supply circuit of engine control systems (Checked with an ohmmeter when the circuits are de-energized or with a voltmeter under voltage) / Clean the contacts, crimp the terminals, replace the faulty relays, wires
  • - Fuel lines, fuel filters are clogged, hoses are pinched, tubes are deformed, water has entered the fuel (Inspection, connect a pressure gauge to the fuel rail inlet hose through a suitable tee - the fuel pressure in the rail must be at least 2.5 kgf / cm2 at idle go.

If it is lower, check the pressure developed by the fuel pump - it should be (at its outlet) at least 3.5 kgf / cm2) / Clean the gas receiver grid, replace filters, defective tubes, eliminate hose kinks.

In winter, drive the car into a warm garage, blow (with a tire pump) the power system from the engine to the gas tank.

If low quality gasoline is suspected, especially on the eve of the winter season, use special fuel additives that dissolve water. After using them, it is recommended to replace the fuel filters

  • - Insufficient fuel level in the carburetor float chamber (When the "suction" button is pulled out, jerks and dips decrease or disappear completely) / To check the fuel level, lift the carburetor cover. Adjust fuel level
  • - Jets and carburetor channels are clogged. Loose jets (Inspect, purge passages and jets / Wash with solvent or acetone and purge jets, if heavily soiled, clean with fishing line or softwood needle (toothpick).

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

  • - The accelerator pump is faulty, its atomizer is clogged or deformed (Check the pump supply, the direction of the jet, the absence of gasoline leakage from under the diaphragm, make sure that the accelerator pump lever moves freely) / Replace damaged parts, tighten the threaded connections, blow out the channels
  • - The injectors or their circuits are faulty (If the windings of the injectors or their circuits are faulty, the KMSUD signaling lamp is on, the fault can be accurately determined by the diagnostic codes) / Check the injector windings and their circuits with an ohmmeter (there is no open and short circuit).

Having disconnected the rail injectors from the engine, check the shape of the fuel jet. Replace faulty injectors, ensure contact in electrical circuits. Dirty nozzles can be washed on a special stand

  • - Intake of foreign air into the inlet pipeline (Inspect the joints, check the fit of the hoses, fittings, tightness of the clamps, briefly turn off the vacuum brake booster by pinching the corresponding hose (carefully: the force on the brake pedal will increase significantly)) / Torn gaskets, parts with deformed flanges, replace defective vacuum booster
  • - Excessive fuel level in the carburetor float chamber (From the exhaust pipe there is a strong smell of gasoline, a cold engine starts better than a hot one) / Remove the top cover of the carburetor, check the float for tightness, ease of movement and absence not touching the walls of the float chamber.

Checking the tightness of the needle valve:

  • - after removing the carburetor cover and pulling the float up with your finger, pump up gasoline with the fuel pump lever. The slightest leak of gasoline from under the needle or valve seat is unacceptable. Replace needle valve, adjust float chamber fuel level
  • - Re-enriched mixture due to gasoline leaking into the engine crankcase through a torn fuel pump diaphragm (Oil on the dipstick smells like gasoline, the low oil pressure lamp may light up at idle speed, idling is unstable) / Replace the fuel pump or its diaphragm; if there is a lot of gasoline in the oil, then the oil
  • - Incorrect ignition timing (Adjust ignition timing)
  • - Faulty ignition distributor (Determined by an auto tester or replacing the distributor with a known good one) / Replace the faulty distributor
  • - The gap between the electrodes of the candles is not correct (Check the gap of 0.7-0.85 mm or 0.8-0.95 mm with a round probe) / By bending the side electrode, set the desired gap or replace the candles
  • - Strong deposits on the electrodes of the spark plugs Entry of carbon particles into the gap between the electrodes (Inspection) / Clean the spark plugs with compressed air or mechanically (do not damage the insulator), make sure they work 4 (no external damage and sparking between the electrodes on the turned out spark plug does not allow us to conclude that it works).

Identify and eliminate the cause of increased carbon formation in the combustion chamber, if necessary, replace the candles

  • - Faulty spark plugs: current leakage through cracks in the insulator or soot on the thermal cone, poor contact in the central electrode assembly (Replace the spark plugs with known good ones or check on a special stand

The absence of external damage and sparking between the electrodes on the turned out candle does not allow us to conclude that it is working) / Replace faulty candles

  • - Wear, damage to the contact carbon in the cover of the ignition distributor. Coal spring loose (Inspection) / Replace distributor cap or coil with spring
  • - The resistor in the ignition distributor runner or the noise suppression resistors in the tips of the spark plugs burned out (Checked with an ohmmeter) / Replace the resistor or runner, tips
  • - Insulation burnout of high-voltage circuits (Checked with an ohmmeter and visually (black cracks, melting of insulation), to check high-voltage wires, replace them with known good ones) / Replace faulty ignition distributor cap, slider, ignition coil / coils, high-voltage wires
  • - The switch is faulty / Disconnect the wires from the ignition distributor, Fix the tip of the high-voltage wire coming from the ignition coil at a distance of 6-3 mm from the 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”. When in doubt, it is better to replace the switch with a known good one - Replace the faulty switch

  • - Weakening or breakage of the springs of the weights of the centrifugal regulator of the ignition distributor, damper rings of the weights are lost, sticking of the weights (Visually and on a special stand) / Replace the ignition distributor
  • - Fuzzy operation of the vacuum ignition timing regulator: when the vacuum is removed, the plate does not return to its original position (Inspection, the characteristics of the vacuum regulator are taken on a special stand) / Eliminate jamming, replace the faulty vacuum regulator or ignition distributor assembly
  • - The crankshaft position sensor or its circuit is faulty (Metal dust has got between the sensor rod and the gear risk, the KMSUD signaling lamp is on, the fault can be accurately determined by diagnostic codes)

Check the crankshaft position sensor circuit with an ohmmeter, the resistance of the sensor itself (850-900 ohms); visually - no 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) Restore contact in electrical circuits, replace the faulty sensor

  • - Several sensors of the engine control system or their circuits failed at the same time (except for the crankshaft position sensor - see above) The indicator lamp KMSUD is on. By diagnostic codes, you can accurately determine the malfunction.

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

  • - The engine control unit or its circuit is faulty. As a rule, the KMSUD indicator lamp is on. Diagnostic codes can be used to pinpoint the problem. to test the unit, substitute with a known-good unit / Swap for a failed unit, rebuild contact in electrical circuits
  • - Faulty fuel pressure regulator (Check the pressure in the fuel rail with a pressure gauge (at least 2.5 kgf / cm2 at idle, and 3 kgf / cm2 at medium speed)) - Replace the faulty regulator
  • - Incomplete opening of the throttle valve / shutters (Determined visually with the engine stopped) Adjust the throttle actuator
  • - The valve timing is broken (Check the coincidence of the marks on the crankshaft and camshafts) Set the correct relative position of the shafts (by marks)
  • - Low compression in the cylinders (less than 10 kgf / cm2): wear or damage to valves, their seats, wear, sticking or breakage of piston rings.

Warm the engine up to operating temperature and remove the spark plugs. Fully press the “gas” pedal and, inserting a compression gauge into the spark plug holes, turn the crankshaft with a starter (work together).

In this case, short the high-voltage wire of the ignition coil to ground and turn off the engine control system 1 (by removing the appropriate fuse or disconnecting the wires from the general power relay of the control system or from the crankshaft position sensor).

Repeat the measurements, pouring 10-15 cm3 of engine oil into the cylinders through the spark plug holes. In those cylinders where the compression has increased by more than 2 kgf / cm2, the rings may be heavily worn, broken or stuck.

If the compression remains below 10 kgf / cm2, wear or damage to the valves or their seats is possible.

Replace rings, pistons, cylinder liners. Repair cylinders. Lap the valves to the seats, if necessary, replace the valves, their guide bushings, grind the seats

  • - Clearances in the valve drive are not adjusted (Checked with a set of feelers) / Adjust the gaps
  • - Severe wear of the camshaft cams (Inspection and measurement after partial disassembly of the engine) / Replace the worn camshaft
  • - Settlement or breakage of valve springs (Inspection, measuring the length of the springs in a free state) Replace settled or broken springs

Slamming in the intake manifold:

  • - Incorrect ignition timing (See Ignition system) Adjust ignition timing
  • - Faulty switch / Disconnect the wires from the ignition distributor. Fix the tip of the high-voltage wire coming from the ignition coil at a distance of 6-3 mm from the 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”. When in doubt, it is better to replace the switch with a known good one. Replace defective switch

  • - The valve timing is broken (Check the coincidence of the marks on the crankshaft and camshafts) Set the correct position of the shafts (by marks)

Shots in silencer:

  • - Incorrect ignition timing (See "Ignition system") Adjust the ignition timing
  • - The switch is faulty (Disconnect the wires from the ignition distributor) Fix the tip of the high-voltage wire coming from the ignition coil at a distance of 6-3 mm from the 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. When in doubt, it is better to replace the switch with a known good one. Replace defective switch

  • - The valve timing is broken (Check the coincidence of marks on the crankshaft and camshafts) Set the correct position of the shafts

new

Procedure for disassembling and assembling carburetors K-151V, K-151E and K-151U Disassemble the carburetor in the following sequence:

Carburetor K-151V (Fig. 1) - vertical, emulsion, two-chamber, with a falling mixture flow and sequential opening of the throttle valves