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Contributor

Re: HEUI Fuel injectors - fuel in oil

hi there....in that case u have to check injector seal for every injector first( visual inspection)..... might be the seal has worn out and it cannot stand the pressure from the cylinder head oil gallery....you also can do injector cut out test to get the correct data for every injectors...

New member

Re: HEUI Fuel injectors - fuel in oil

This is common failure of C9 injector, inside the injector leaking, not the seal outside. Normaly, you immediately suspect fuel leaks from fuel transfer pump, because it is conected to the HEUI pump. But 3yrs working with C9, I've never met it.

Trusted Contributor

Re: HEUI Fuel injectors - fuel in oil

The oil samples should confirm if there is fuel dilution.  If there is fuel in the oil, the engine can have a power issues due to the oil being thined out and the HUEI system not being able to make the correct pressure to fire the injectors properly.  As far as the fuel entry in the system, it is probably the seals on the fuel injector leaking.  It could also be the fuel transfer pump. Is it making engine oil? That would give an idea how much fuel is getting in. 

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HEUI Fuel injectors - fuel in oil

I have a customer that is having issues with fuel in the engine oil in his CAT equipment that is equipped with the HEUI Fuel System.  He feels that the oil is not holding up, so it is not operating the HEUI fuel system correctly, causing the fuel to mix into the engine oil.  His thoughts are based on the oil analysis report, that there is fuel in his oil.  He is using a quality product and changing the oil a bit under the recommended guidelines.  Has anyone had any issues with this?