Diagnos my problems.
 

I have a Suburban I put a Cummins into a couple years back. It was a VE motor, but I swapped in a P Pump. I have been running it a few months with loads of problems. First it doesn't run as smoothly as it did as a ve motor it just is not as smooth. Then I started having problems with it falling on its face during acceleration. I pulled the return banjo bolt and when I did it came out with what looked to be a helicoil. I couldn't get a helicoil and new bolt into the pump but I found an injection bolt from something else that I threaded in a put the return bolt down stream from the pump. It seemed to work fine, but I took the Suburabn to tow home a couple of cars and ended up spending a lot of time on the side of the road. It appeaars the new return banjo bolt is failing and I couldn't get the fuel to stop flowing out of the return enough to build any sort of power. I finally crimped down the return feed with some vise grips and got it to run home with good power. However it doesn't want to restart. I am going to take the pump off and put a new return in, should I have it gone through while it is off? Should I just buy a used pump from someone here? I noticed a p-pump in the for sale section that recently sold that would have been perfect. I am just wondering how to proceed on a budget.

John

what about your ofv and have you checked pump pressure:humm: lift pump that is

The VE lift pumps were less pressure....you need at least 17psi at idle as that is what Cummins specs the stock P-pump LP at. You can ditch the OFV and put an inline regulator in the return line. Just make sure it has Viton seals so the diesel won't eat it. Then you can adjust the pressure. That's all the stock OFV is. If the out port on the pump is stripped you could tap it for a NPT fitting and then just run rubber line to the regulator and set the pressure with it. I think that is most of your issue. Timing might be another but get that fuel pressure set right and go from there. Just you mentioning pinching off the return line and the truck ran fine tells me the OFV is the issue and there isn't enough pressure in the system as it is basically free flowing past.

It has a new piston lift pump
 

I also put a new over flow valve inline recently and I am perplexed that it is having the same problem. Do you have a link for an inline regulator?

Let me see what I can dig up tomorrow for you. It's going to have to be an EFI regulator as they operate at the higher pressures. I know Aeromotive, Mallory and Mangnafuel make some....they are alcohol compatible and that means viton seals.

I have seen a lot of these being used.

I think part of your problem is your fuel press as already mentioned.
Few questions ... What did you set your timing at? what injectors are you running? have you checked to make sure the shutdown soleinoid is pulling up while cranking? What fuel plate if any are you running? Are you running a AFC and have you made sure there are no leaky air lines to it?

I also got your PM and I will let you know if it falls through

One like this:

Aeromotive 13101 - Aeromotive A1000 Injected Bypass Fuel Pressure Regulators - Overview - SummitRacing.com

yep just like that