Dieseling/Run-on
SYMPTOM DESCRIPTION:Engine continues to run after key is turned "OFF", but runs very roughly. If engine runs smoothly, check ignition switch.
SYSTEM OR COMPONENT TO CHECK
FUEL SYSTEM
CHECK
- INJECTOR LEAKAGE: Check fuel system residual pressure, perform injector ballance test. Look for leaky injector(s).
- FUEL PUMP RELAY: Fuel pump should turn "off" when ignition is turned "off".
ENGINE
CHECK IDLE SPEED: Idle speed is computer controlled, if idle speed is incorrect, refer to Computers and Control Systems and see IDLE STABILIZER VALVE under COMPONENT AND CIRCUIT TESTING.