So here is the deal I had another thread seems to have died I know patience but its my Dr and its getting old. Rail pressure drops to 11 k at wot and then when I let off spikes to the desired of 23.5k. So on the other thread they said unplug the connector on the back of the fuel pressure regulator and if it goes to 23 k and stays there then its bad fpr if it goes up and down the I have stuck injector. So I unplug the fuel pressure regulator did not move from what it was at. At idle. So my question is where do I go from here. My balance rates are all +/- 2.5 and just extra info with lift pump on it will have actual rail pressure at idle be 2-5k above desired that also makes me lean towards the fuel pressure reg. Let me know
i dont know what to do here fuel problems
- Thread starter mch646
- Start date
Unplugging the fpr connection should make it go to about 26k. But anyways, with your situation, I'd say it sounds like your fpr is no bueno. Does your truck surge at all if you stay steady at around 10mph?
I think I have a known good fpr that's a spare. I could send it to you so you can bolt it in. That will help you to either A) let you know your fpr is bad. Or B) let you know it's good and the problem exists elsewhere.
Pm me if you get to the point that you wanna try it. I will need the fpr back though. Unless it solves the problem and you just wanna buy it at that point.
I think I have a known good fpr that's a spare. I could send it to you so you can bolt it in. That will help you to either A) let you know your fpr is bad. Or B) let you know it's good and the problem exists elsewhere.
Pm me if you get to the point that you wanna try it. I will need the fpr back though. Unless it solves the problem and you just wanna buy it at that point.
No it doesn't run rough it sounds really Ricky in the mornings cause of the high rail psi but it runs like a top I know it's bad though cause on my edition live dsp5 on the edge insight I can't get more than 2150 us out of her even on the high 300+ horse tune so there is a problem somewhere and during unplugging the fpr today it threw several other codes u1041 p0089 p0090 p1093 which would be the connector being unplugged and p0530 and p0522 and they keep really appearing now that's besides the point and a different thread but just throwing that out there that I might have a bad connector somewhere
When you get a chance, fill out a signature so we can see what mods you've done, mileage, history, etc...Might make it easier to troubleshoot...
I picked 10mph as a random low speed. Bucking/surging is common with bad fpr's. I had an fpr once that would buck and surge at 25mph on cruise control 
For what its worth. Im not sure if their is a write up or not but all you need to do is pull off and disasemble the fuel pressure relief valve and put a piece of threaded rod in place of the spring so that it cant open or some have just welded them shut.