Engine Starts but Will Not Run at Idle
- Incorrect slow idle adjustment.
- Fast idle solenoid not functioning.
- Fuel return system blocked.
- Glow plugs turning off too soon.
- Injection pump timing incorrect.
- Insufficient fuel going to injection pump.
- Incorrect or contaminated fuel.
- Low compression.
- Injection pump malfunction.
- Fuel solenoid closes in "RUN" position.