Diesel as well as gasoline engines employ high pressure fuel pump and they are important when using direct injection and common rail. However, these pumps can face issues that impact vehicle performance.
The OSIAS Mini Cooper high pressure fuel pump (SKU: MINIG) is a 100% brand new part, featuring a 2-year warranty and compatible with part numbers 13517588879, 13537528345, and 13517573436, all provided in the original OSIAS package.
In this post, we will discuss common faults and potential solutions for these pumps.
1. Diesel Engine Won’t Start
The low-pressure oil circuit’s incapacity to provide fuel to the high-pressure pump is a frequent cause of diesel engine failure to start.
This can be brought on by:
- Air in the oil circuit: Often seen in idle engines; remove air by using the hand pump and loosening the bleed screw.
- Blocked low-pressure oil circuit: Dirt clogging filters/screens; clean or replace parts.
- Oil pump failure: Worn/damaged pump piston; repair or replace the oil pump.
- Leaking oil delivery pipes: Tighten loose connections or replace damaged pipes.
2. Weak Engine Performance
The high-pressure fuel pump’s inadequate fuel supply is usually the cause of a diesel engine feeling weak or underpowered.
Common causes include:
- Oil supply pump issues: Worn oil pump piston or deformed check valve; clean or replace defective parts.
- Wear in high-pressure fuel pump components: Worn plunger coupling, oil outlet valve spring, or seal; replace damaged parts to restore fuel flow.
3. Engine Running Rough
The high-pressure fuel pump may be the source of an uneven oil delivery if the diesel engine is rough, especially when it is idling.
Possible causes include:
- Uneven fuel supply: Fuel supply to cylinders is uneven, causing instability. Adjust the oil supply on a test bench.
- Faulty governor: Stiff flyweight or worn transmission parts reduce governor sensitivity. Replace these parts.
- Incorrect idle speed adjustment: Low idle speed exacerbates fuel supply issues. Adjust the idle speed limit screw to resolve this.
4. Engine Failing to Reach Standard Speed
If the engine fails to reach the desired speed, the issue may be with the oil quantity control gear rod of the high-pressure fuel pump.
Possible causes include:
- Control handle issues: The handle may not be fully engaged with the maximum oil quantity limit screw. Check the secondary throttle limit screw and ensure the control handle is unobstructed.
- Governor spring issues: A soft or elongated spring may lack sufficient tension to regulate speed. Replacing the governor spring will restore proper engine performance.
5. Diesel Engine Running Away (Flying Car)
A serious issue occurs when a diesel engine runs uncontrollably at high speed, also known as “flying car.” This is often due to the high-pressure fuel pump’s oil volume control rod malfunctioning.
Immediate emergency measures include:
- Fuel cut-off: Release the accelerator till it reaches the position where the fuel supply gets cuts off in the inlet pipe.
- Shutting off air: Block the air inlet to stop the engine.
- Stopping the engine: Shift to a higher gear and apply brakes to force the engine to stop.
Conclusion
High-pressure fuel pumps and governors are vital for diesel engine performance. Regular inspection, cleaning, and part replacement ensure optimal fuel pump function, preventing costly repairs and maintaining engine efficiency. Consult a professional for serious issues and perform test bench maintenance when required.
