My dad has a 91 dodge that today lost oil pressure. We checked the oil and noticed diesel in the oil. After investigating further we realized diesel was being blown out of the breather hose. My question is did we just lose a gasket or did the injection pump go south.I appreciate any help I can get. Thank you.

 

You have a bad fuel pump. They "make oil" by leaking into the crankcase.
-Jim-

 

Yep, it sounds like the lift pump diaphram let go, just like the ones on the old carburated Chevy small block. They would dilute the oil with gasoline, BANG!
Wanna said something about changing over to a piston style lift pump like what is on the second gens. only putting out lower pressure to prevent damaging the VE pump. Mine hasn't gone south yet so I haven't looked to far into changing it. Seemed to be pretty straight forward swap. Some of the sound insulation on the lifter cover will need to be excavated for it to fit.

 

Howdy,

Boatnik's right about both, the better pump is the piston pump...but you need to use the correct part number pump, not just any piston pump.

The cost is also quite a bit more than just a stock replacement pump too...here's the numbers and approximate prices. When I orderred mine it was a bit more...



Pump,Fuel Transfer P/N#3936320 $153.23
Gasket, Cover Plate P/N# 3639258 $1.75 ea (2 required)
Tube, Fuel Supply P/N# 3914753 $29.29
Spacer, Mounting P/N# 3914284 $10.40
Washer, Sealing P/N# 3963983 $1.00ea (2 required)

Hope that helps,
Vinny

 

I find it very interesting that the same "diesel fuel in oil" would have been diagnosed as a leaking injector on the 3rd gen forums.

Rick

 

Fuel in oil can come from leaking injector, lift pump or injection pump shaft seal.

 

Thanks for the info. We have a place to start and I will post the results when we find the exact problem.

 

That's because there's no connection between the lift pump and the engine/oil in the 3rd gens,
especially the ones with the pump in the tank.
Same thing with the 24 valve 2nd gens, is just mounted to the block, no path for fuel between them.

Only thing left is a leaking injector.


phox

 

another bad lift pump, it seams winter fatiges that part more than ever