Diagnostics of malfunctions of the injection system and power supply
Cause | Remedy |
Motor shaft rotates oval, high fuel consumption, low engine power | |
Faulty injectors | Replace nozzles. |
Nozzles leaking (drops), polluted | Replace nozzles. |
Stuck or broken nozzle needle | Replace nozzle needle. |
Displaced pump start | Check pump start adjustment. |
Faulty high pressure fuel pump | Install a new high pressure pump. |
The engine has a mechanical defect; leaky valves, worn cylinders/pistons, leaky cylinder head gasket, narrowing in the exhaust system | Check compression, check engine mount/engine shaft bearing. |
Troubleshooting at idle | |
Difficult cable travel when pressing the accelerator pedal | Adjust the throttle cable so that it moves easily. |
Oval movement of the motor shaft when idling and a cold engine, too high speed when the engine is warm | Check vacuum hoses for increased idle speed. |
Loose fuel lines at high pressure fuel pump and fuel filter / Faulty fuel lines | Check tight fit, replace tubing if necessary. |
Loose screw connections on high pressure fuel pump | Check the base plate for cracks or breaks and replace the piping if necessary. |
Faulty fuel supply system | Dirty fuel filter, leaking or dirty fuel return lines and high pressure fuel lines or fuel tank vent line, bent or narrowed at the connections. |
Too high fuel consumption | |
Air filter dirty, power system leaking | Clean or replace filter element. Visually check the tightness of all fuel lines (intake, drain, high pressure fuel lines, fuel filter and high pressure fuel pump). |
Clogged drain line | Loosen the drain hose on the high pressure fuel pump. Start the engine and check if fuel comes out. Blow air through the drain line from the high pressure fuel pump to the fuel tank. |
Engine idling speed too high | Check the engine idling speed and see if it can be reduced. |
Engine power too low | |
Test prerequisites: speedometer readings must be normal; tire size to match the standard equipment; wheels (brakes, bearings, wheel hubs) must be locked, the clutch and clutch control actuator must be in good condition; the break-in process must be completed. Speed must not be reduced with additional equipment (luggage on the roof, etc.). To determine the maximum speed, it is recommended to drive a flat test area in both directions, approximately 1000 meters, in order to determine the maximum speed with a stopwatch. | |
The stop of the throttle lever, which limits its maximum opening, is not reached | Adjust the throttle cable. |
Air filter dirty | Clean or replace filter element. |
Air bubbles in fuel line from filter to fuel pump/high pressure fuel pump | Check the fuel supply line and filter. Fuel filter loose or leaking; leaky fuel supply line between the tank and the fuel filter; line connections on the fuel filter are leaking. |
Faulty fuel lines | Visually check the tightness of all fuel lines (inlet, drain, high pressure fuel lines) from the fuel filter and high pressure fuel pump. |