David454

Alright, so @Mopar1973Man I can tell you are real proud of your knowledge on snubber fittings and everything, but that was not my issue. The fuel pressure sensor is right on my Fass and now reads rock solid pressure. Thank you @Dieselfuture for the tip on the check ball, that ended up being the cause. The truck sat for a long time before I bought it and the ball had a nice grove worn in it all the way around and was sticking. I turned the check ball 90 degrees and haven't had a fuel pressure blip since. (I still plan to get a replacement ball/spring) After looking at everything I had going on back to the beginning, I think that the jumping fuel pressure was the root cause. The truck would run fine for a few minutes and then start having issues. I think the pump was heating up due to lack of consistent fuel, the timing piston was starting to lock up and burning up the wires going to it. I fixed the check ball issue and the truck ran fine with the two bare wires going to the timing piston basically in the open, only enough electric tape to keep them from grounding out on the pump. So I know the sheathing wasn't part of it either. Before the fuel pressure would jump from maybe 12 to 18 on my edge monitor, and you could hear the pump pulsing clearly while the issues were happening. Now FP is rock solid between 15-16.5 psi depending on throttle position and fuel temp. Pump sounds smooth and consistent. I know that during this mess (I probly put 800 miles on the truck with the fuel pressure jumping like that, solid 200 of that towing 9k+) the injection pump had to have taken some permanent damage, and it was original with 160K on the clock so I put a reman pump in from DAP and it has been doing great for the ~500 miles since then. Thanks again for all the help gents! I hope people can use this to solve some of their problems down the line, as I know I have 100's of old threads before it.

My sensor is basically on the pump from what I can tell, no sensor anywhere near the vp, and wiring to what looks like a sensor right on the pump. Is that the correct way to do it? I have no idea how the rest of the suction side is set up but I will find out soon it looks like. Need to call the guy and see what all he did when putting in the FASS. I know he had the bed off at some point so hopefully the hard parts are there and it's just a loose clamp somewhere. The pump has a return line up to the filler neck, which is where I hear that splash of fuel every second or so with the coinciding pump noise surge. I am looking at vp44's from DAP. Looks like it's an extra $175 for the new computer. That's worth it I would assume?

Well after approx an hour and a half of running great yesterday (with several starts and stops) it went into some kind of limp mode last night right after I started it from sitting for a couple hours. Throwing one code - P0216. I inspected those timing solenoid wires and there was clear evidence they had gotten very hot, whether it was from shorting or the pump heating up I am not sure due to another issue I found outlined below. I took the electrical tape off and the wires to the timing solenoid are frayed much more than they were from getting hot I assume. In some initial trouble shooting for P0216 I swapped the fuel filters on my fass and noticed the pump was surging bad at idle (post bleeding everything of course). I can open the fuel cap and here the fuel splash into tank in sequence with the pump surge (every second or so). Fuel pressure on my edge shows a bounce of a couple psi but always above 12. I'm assuming there's an air leak in the intake for that FASS somewhere causing some issues. This is all adding up to it looking like I just bought myself a vp pump, and I need to redo the FASS pickup line. I plan to try and redo the timing solenoid wires in a better way tomorrow and see what the deal is with the pump surge. I figure that regardless of getting it to run right now, that the VP is damaged from air in the lines. This is my first vp-44 truck and I've had it less than 2 months, already had to rebuild the nv5600 because I found metal chunks during a service. Coming from 3rd gens and still having a p-pump 12v, this truck is making me think anyone that keeps one of these vp trucks is crazy. I've spent more on this truck than the other 3 Cummins I've had combined and I've only put 500 miles on it. lol, thanks for all the replies and help though! Yal are great.

Them being stainless would make sense, definitely didn't look copper. Resistance to ground was less than 1 ohm from any plug I tested, I used dielectric grease on all the connections when I plugged them back in. I had tried 4-5 other things that I didn't include in the post trying to fix it and nothing changed anything till I started adding more insulation to those two wires. Seems like to me the OEM sheath I cut off trying to find the end of bare wire was important after all. I tried to measure the AC noise from the alternator post to pass side ground on the battery and my volt meter isn't fancy enough to show anything. If it is AC noise in the system is there anything I need to do about it if the truck is running fine now? I guess I need to get ahold of a good volt meter and check it if so.

Sheathing was halfway gone, wires showed no signs of ever being individually insulated and had bare wire showing wherever the sheath wasn't. This morning I took some aluminum foil, folded it up in about 5 layers, wrapped it in electrical tape, and made a sheathing for those two wires then grounded the sheath. I've driven about an hour and a half this afternoon and the problem hasn't come back. Those two wires aren't in a bundle with other wires but are next to the vp's computer. Makes me think there is some kind of electrical noise coming off the pump that the original sheath was supposed to shield from (more than electrical tape could do). When I poked them originally (cause I couldn't believe my eyes that there were bare wires hanging out), it might have pulled down the sheathing just enough to expose the wires to noise and start the issue. My first attempt to fix it was by cutting off the excess sheath that had ripped and wrapping it in electrical tape. I think in that case enough of the original sheath was gone that no matter how well taped they were it needed a real noise isolating sheath. Who knows, the way things are going, the next time I start it up I might be right back where I started.

The blue traced wires are what I'm referring to.

I've done everything on the diagnostic guide but #1, and I have a FASS and don't understand how to measure AC voltage across a plug when the truck needs to be running to do so. I unhooked the alternator and nothing changed, so shouldn't that remove the AC voltage issue from the alternator?

I've got an 01 6 speed HO with 160k on it I bought not too long ago. Previous owner had installed a FASS and Edge Juice on it. I went to clean up some line routing/wiring and noticed what I now know to be the timing solenoid wires were completely bare at the top outside the sheath. I poked around that area a bit, looked over some fuel pump wiring/hoses and then quit for the night after I saw how much work I needed to do. Next day I fired it up (still hadn't done anything but literally poke the wire bundle around to look at it) idling rough, p1690 pops up (no other codes) I shut it down and decided to swap the crank sensor. No change with the new crank sensor, so I went through the rest of the diagnostics I had found on here with no luck. All wiring to the ECM and Cam sensor is sound. All wiring from the vp is sound, grounds are good (less than 1 ohm on my volt meter). I don't know how to check the AC noise from the lift pump but I have a FASS so I would hope it's fine. I decided to look more at the bare wires for the timing solenoid I had poked, found that there was no evidence of ever having insulation on them (I found other pics of similar situations that seemed like they came factory like that). I wrapped them in electrical tape the best I could, started it up and wala, no codes and idling well. 5 min into the drive I heard the timing change and the CEL popped back up, no power of course, with the same one code p1690. Back to the way it was. I figured my electric tape job might have been the fix but just not done well enough, so I redid that with some liquid tape added too, and this time only got a minute or two into the drive before the issue came back. Also during this process I tried unhooking the alternator and didn't notice any difference. Tried letting it get back completely cooled off without touching the tape and still having issues so I'm not convinced it is engine temp related. Only other pertinent information I can think of is that it got below zero here last week and I'm sure the fuel gelled, but I didn't drive it until the temps were over 40 degrees. It always showed good fuel pressure (13+) and made an hour round trip the day before the issue started without a problem. Could the fuel gelling cause pump issues inside it or some residual wax floating around cause issues even after over on hour of trouble free run time since temps were below freezing? Do yal have any other ideas on what this could be? Truck is undrivable at this point.