FUEL IN OIL 2010 CUMMINS ISC 8.3

Not a cummins owner, but I have the same issue (volvo)

Changed out the fuel pump - thinking it was the problem. That did not solve it.

Thought it was injector seals....but when we took the top cover off, did pressure test...we found a crack in the head (along a fuel supply line). The head has internal channels to deliver the fuel.

Put everything on the table, and start eliminating them as you go.

 

ISC only has return rail in head.

 

Hmmmm....While I appreciate your statement, I'm curious as to what that implies w.r.t to "supply" or "return" aspect.

Can you clarify please?

 

I totally agree with you, just letting OP now it only has low pressure return rail in head. High pressure is from quill tubes from fuel lines from common rail. He is making oil fast, so think issue would be from somewhere with higher volume of fuel, ie cracked injector or leaking HP pump. Both are common leak points on this particular engine. Your advise was solid and I "thanked" it because of that. Remember, we are all in this together.

 

@spsauerland Oh. my bad. I was not "questioning " your statement.

It was more of curiousity on my end, since right at the back of the head, is my return line too, and it's near cyl/injector # 5....where the crack is.

Your explanation of the high pressure (supply side) vs. low(er?) pressure on return helped.

I'm trying to understand the root cause of my truck's heads crack, so that I don't end up with the same issues (on a new head), should there be other triggers that I have not thought about.

 

If you do suspect an injector, injectors..... drop the pipe off at the dpf, enter dyno mode in Insite and perform a snap accell test for smoke. Surely if it' s overfueling to the point of washing a cylinder and overfilling the crankcase it should show its face as black smoke during the test. Regen history should also reflect this over time with increased frequency and higher that normal temps or possibly face plugging and low temps in severe conditions.

Dyeing the fuel is an excellent idea also. I've never seen a pump or injectors leak like that on this engine ,but surely could be a possibility.

 

We have had fuel pumps leak internally to the engine.

 

DOCs do no last forever and degrade over time. This results in incomplete burns and soot loading in the DPF. DOC and DPF need to be remove and cleaned periodically as regular maintenance. I would do this first. If problems continue after that and you still have the original DOC, I would say it has come to the end of it's life.