Symptom Related Diagnostic Procedures
PROCEDURESYMPTOM: FUEL PRESSURE TOO LOW.
Probable Cause;
- Clogged Fuel Filter.
- Fuel leakage to the return side caused by internal leakage of Fuel Pressure Regulator.
- Low discharge pressure of Fuel Pump.
SYMPTOM: FUEL PRESSURE TOO HIGH.
Probable Cause;
- Sticking Fuel Pressure Regulator.
- Clogged or bent fuel return hose.
SYMPTOM: THERE IS NO DIFFERENCE IN FUEL PRESSURE WHEN THE VACUUM HOSE IS CONNECTED AND WHEN IT IS REMOVED.
Probable Cause;
- Clogged or damaged vacuum hose or nipple.
- Sticking or poor seating of the Fuel Pressure Regulator.
SYMPTOM: FUEL PRESSURE DROPS SLOWLY AFTER ENGINE IS STOPPED.
Probable Cause;
- Injector leakage.
SYMPTOM: FUEL PRESSURE DROPS IMMEDIATELY AFTER ENGINE IS STOPPED.
Probable Cause;
- The check valve within the Fuel Pump is open.