Diagnostics of faults in the injection and power supply system
Cause | Method of elimination |
Engine shaft rotates oval, high fuel consumption, low engine power | |
| The injectors are faulty | Replace the injectors. |
| The nozzles are leaky (drops), dirty | Replace the injectors. |
| The injector needle is stuck or broken | Replace the injector needle. |
| The pump feed start is shifted | Check the pump start adjustment. |
| The high pressure fuel pump is faulty | Install a new high pressure pump. |
| The engine has a mechanical defect; leaky valves, worn cylinders/pistons, leaky cylinder head gasket, restriction in the exhaust system | Check compression, check engine mount/engine shaft bearing. |
Problems when running in idle mode | |
| Heavy movement of the cable when pressing the accelerator pedal | Adjust the throttle control cable so that it moves easily. |
| Oval movement of the engine shaft when idling and when the engine is cold, too high rotation speed when the engine is hot | Check vacuum hoses to increase idle speed. |
| Fuel lines are not secured to the high-pressure fuel pump and fuel filter / fuel lines are faulty | Check for tight fit, replace line if necessary. |
| The screw connections on the high pressure fuel pump are loose | Check the support plate for cracks or breakage, replace the pipeline if necessary. |
| The fuel supply system is faulty | The fuel filter is dirty, the fuel drain lines and high-pressure fuel lines or the fuel tank vent line are leaking or dirty, kinked or restricted at the connections. |
Fuel consumption too high | |
| The air filter is dirty, the fuel system is not sealed | Clean or replace the filter element. Visually check all fuel lines for leaks (intake, drain, high-pressure fuel lines, fuel filter and high-pressure fuel pump). |
| The drain hydraulic line is clogged | Loosen the drain line 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 speed too high at idle | Check the engine idle speed and the possibility of reducing it. |
Engine power too low | |
| Check prerequisites: the speedometer readings must be normal; tire size must match serial equipment; wheels (brakes, bearings, wheel hubs) must be locked, the clutch and clutch control drive must be in normal condition; the running-in process must be completed. The speed must not decrease with additional equipment (luggage on the roof, etc.). To determine the maximum speed, it is recommended to drive a flat test section in both directions, approximately 1000 meters, in order to determine the maximum speed using a stopwatch. | |
| The throttle lever stop limiting its maximum opening is not reached | Adjust the throttle control cable. |
| The air filter is dirty | Clean or replace the filter element. |
| Air bubbles in the fuel line from the filter to the fuel pump/high pressure fuel pump | Check the fuel supply line and filter. The fuel filter is loose or leaking; the fuel supply line between the tank and the fuel filter is not tight; the linear connections on the fuel filter are not tight. |
| The fuel lines are faulty | Visually check all fuel lines for leaks (intake, drain, high pressure fuel lines) from the fuel filter and high pressure fuel pump. |