2013 ISX15 Cummins fuel trouble!

I can get one tomorrow. Anything specific you want to see?

 

here is the fuel lift pump.

 

I went and bought an oil sight glass plug and used a T fitting to plumb it in. I bypassed the housing using this and it runs better BUT, I can see the flow of fuel in the bottom of the T. Doesn’t seem like it’s flowing much. I’m also seeing bubbles at this location, with or without the engine running. Currently the engine is off and I’m seeing more bubbles forming almost consistently.

 

I also used a 5 gallon diesel can yesterday on the small supply line that goes from the priming pump to the frame mounted filter housing and it did not change how it runs. It does appear that this supply line goes under the pump to a block that the pump is mounted to.

 

engine off I was getting bubbles. I do not know if that’s actually from air getting in the system or if it’s from my T fitting here that I made for the sight glass. It also could be sucking air for all I know. I pulled the lower elbow off under the priming pump and there is no screen there. It also appears that the high pressure pump might actually take over with sucking fuel as I can see through the inside to where the line comes in from the main pump. I took the spin on filter off and found nothing wrong there either and installed a new filter there. As for the frame mounted filter I’m not sure what you mean by pull through but I’m guessing it is. It draws from the top of the filter bowl. So that housing MUST be full at all times to work properly. There is no pick up tube on the center of the water separator filter.

 

Fired up, still having the same problem.