Possible cause of failure | Remedy |
Fuel supply pressure too low | |
Clogged fuel filter | Replace fuel filter |
Leakage of fuel through the drain circuit due to a leaky installation of the fuel pressure regulator | Replace fuel pump |
Fuel supply pressure too high | |
Stuck Fuel Pressure Regulator | Replace fuel pump |
Clogged or pinched drain hose or fuel line | Replace hose or fuel line |
Fuel pressure slowly decreases after engine shutdown | |
Fuel leakage through injectors | Replace nozzles |
Fuel pressure drops immediately after engine shutdown | |
Fuel pump check valve stuck open | Replace fuel pump |
When troubleshooting an engine, start with a performance check and inspection of major systems. If the engine is malfunctioning, erratic idle speed, or insufficient acceleration, check the following main systems:
1. Power supply
- Battery
- Burnt-out jumper
- Fuse
2. Connections with «weight»
3. Fuel supply
- fuel line
- Fuel filter
- Fuel pump
4. Ignition system
- Spark plug
- High voltage wires
- Ignition coil
5. System for reducing the toxicity of exhaust gases
- Crankcase ventilation system
- vacuum leak
6. Others
- Setting the ignition timing
- Idle speed
Malfunctions of the MFI system are often caused by poor contacts in the wiring harness connectors. Therefore, check the reliability of the connection of all connectors.