Fuel in the Oil,,..?

[Darrin Tosh]

I picked up a 7.3 motor today with 128 K on it It was put in a truck and 5k Later they said they were getting fuel in the oil. It ran great, no stumbling and plenty of power. The lift pump was changed out, and the injection pump was also checked out and no problems were found, the ford shop couldn't figure it out. So they pulled the motor and had a rebuilt one installed.

Any suggestions on what it could be? I may be able to use this motor in the near future but I want to fix it first.

Thanks!

 

[rancherman84]

well if you break it down there is really only three spots that the engine oil and fuel can mix.
1 the transfer pump,which you say was changed
2 the injection pump,which you say was checked.how did they check it?usally the umbrella seals will leak before it transfers fuel to the oil.
3 could be a stuck injector,allowing fuel to leak past the rings and into the crankcase.
thats my thoughts,but after the summer i've been having i'm starting to belive anything

 

[93turbo_animal]

well also how much fuel was in the oil and what was their driving habits I know you can get a lot of fuel by the rings if you just starting it up and moving it and shutting it down with out getting it warmed up

 

[f-two-fiddy]

Extended idleing with a bad injector?
Double check the lift pump. We all know how things can be bad out of the box.

 

[Agnem]

Swap the IP and run an electric fuel pump on it. Problem solved.

 

[geonc]

Extended idleing with a bad injector?
Double check the lift pump. We all know how things can be bad out of the box.

that would have produced the same effects as a mosquito sprayer
The tip would have had to have been blown off past the holes and the seat hung open to put the amount of raw fuel in the crankcase.

I'm with Mel

 

[wanderer]

I'd say simplistic things first. Bad o-rings on the injector/s. 128K on the motor is about the time to be replacing o-rings, not pumps.

 

[highest_vision]

Maybe consider pressurizing the fuel tank and checking for leaks at the inj pump. Maybe the drain for the valley is plugged and fuel is going into the engine via the cdr drain. Or injector returns. Maybe one (or more) of them was leaking.
James

 

[Darrin Tosh]

Swap the IP and run an electric fuel pump on it. Problem solved.

Sounds like a plan, when I need to use this motor that is what I will do. Ken will install it so he can swap out the pump with another one that I have when he gets it.

Thanks for all the input,

 

[bikepilot]

A thermostat stuck open causing the engine to run too cold will usually result in oil dilution as well.

have fun