CodyBeasom

Alright, hopefully this is the final update on this thread. Got the pump reinstalled early last week, and decided to take it for a drive with the new pcm I installed to establish a fresh benchmark before I swapped the old one back. Drove the truck about 45 miles and the issue was gone, ran great. Strange. Drove it another 45 and still everything is fine. Drove it to work everyday this week and haven’t had an issue. I even hooked it up to my flatbed and towed my skid steer and welder about 60 miles this weekend and didn’t had a problem. I did notice the rpm bounce slightly when returning to an idle from above 1500, particularly dropping from third to neutral but it’s not like it was before, and the truck isn’t acting like it wants to stall anymore. I checked the oil pretty religiously and there was a little diesel in it still but not like it was before, changed it a few days ago with a fresh filter and I don’t seem to be mixing fluids anymore, at least not anywhere near the way it was. I’ll have to keep an eye on it and change it again to make sure, but for now it seems to be fine. So... basically it seems to have fixed itself. The only thing I did different when I reinstalled my injectors and pump this time after having them tested, is I bought a brand new inch/lb torque wrench that I used to torque the hold down bolts with. Everything thing else I’ve done the same since the first time I installed all of those parts. Maybe my old torque wrench was junk and I wasn’t getting enough torque on the injectors? For now everything seems to be fine. I really appreciate everybody’s input and knowledge, and I’m sorry the whole thing got spread out over a few months, just didn’t have a lot of time to work on it lately. Kinda feel like an idiot if indeed it was just a torque problem and just throwing money at it but... live and learn I suppose.

Finally have an update on the truck. Got a call from industrial injection and they finally got around to testing the pump. They found nothing wrong with it. They couldn’t get it to leak from the shaft seal, but they replaced the seal anyway. They also ran it on the test bench and found nothing wrong, so it’s on the way back to me now. Great customer service, although it took a little bit for them to get to it, but I didn’t have to pay for it so I understand. I must have just seen really thin oil mixed diesel flying off of the shaft nut rather than just diesel and I just jumped to the last logical conclusion I could think of. That or I’ve gone crazy. Regardless I can officially rule the pump out now. For now, if I ignore the mixing fluids problem, assume it’s just residual diesel from maybe the old injectors leaking, and just focus on my running issue, the last thing I can think of is the ecm I put in the truck. It did solve my initial problem of hard starts when the truck was warm, but I swear it seems like the injection timing is worse than it was before. It didn’t try to die quite like it does since swapping them out. The rpms would still bounce a little though. It’s hard to remember now because so much time has passed and I barely even got to drive the truck after buying it. I’m not sure if I can have one of those tested, and I don’t have another truck to plug it into. I do actually have the old ecm, so when I get the pump back, I’ll put everything back together and put the old ecm back in and see if the running issue is still there. I know it’ll hard start, but I’m curious if it’ll run better and quit trying to stall itself out when my foots not in the throttle.

Just got off the phone with a guy at industrial injection. He also was surprised to hear that the seal was leaking, but said the pump was still under warranty and to ship it off to them so they can test it, replace the seal if necessary, and make sure nothing else is wrong with it at no cost to me. I put a couple paint pen marks on it and took pictures just to be safe, but it doesn’t sound like I’ll have a problem with them though. I just hope they find the pump to be a dud so I can finally put this issue to rest.

I’ll keep you posted. From what I read on their website it should be under a one year unlimited mile warranty. I’ll have my fuel pressure confirmed with another gauge soon to rule that out.

That’s what I was told, which is odd because my fuel pressure doesn’t exceed 20 psi. The highest my fuel pressure gets is 18 psi at idle, so it’s close to 20 but not at a pressure I would expect to blow through a shaft seal. A friend of mine who’s worked on these trucks for years said he’s come across one reman vp44 that leaked from the shaft seal which he verified with dye in the fuel. That’s the only one I or he has ever heard of on a stock truck.

That’s what I plan to do tomorrow, don’t know if I’ll get a hold of anyone today. Hopefully they’ll work with me.

Reinstalled the pump and ran the truck this weekend. Fresh oil change and filter. Same problem. Runs rough as soon as it starts warming up, likes to stall returning to an idle and still mixes fluids, no white smoke, no coolant loss. In less than 40 miles of driving and idling in my driveway for about 20-30 minutes, then shutting it off and letting it settle, the level on the dipstick was about a 1/2” past the safe mark, green and smelling of diesel. I took off the inspection cover for the vp44 shaft nut to see if it had any fresh diesel on it and found it covered in diesel. I ran the truck with the cover off and I could see diesel spraying off the nut and all over my inspection mirror. Looking like the shaft seal might be my culprit for mixing fluid. Not sure why I didn’t think to do that earlier but oh well... Pretty sure I can replace the seal, but I might still send the pump off to have it checked. Maybe the psg has a malfunction when it starts getting warm that’s messing with my fuel injection timing.

The arrow is pointing toward the pump.

Finally have an update, been a hot minute since I’ve been able to get back to the truck. This past month has been pretty crazy. Got the injectors tested, and they are all perfect. Pop off pressures are the exact same for all six, and within spec. None were stuck or hanging up, or leaking. I went ahead and popped the injectors and connecting tubes back in the truck, but haven’t torqued anything down yet. The tech at the diesel injection shop told me to check my injection pump and make sure I had that key indexed right and didn’t smash it or it didn’t shear off. He also told me to check for a restriction in my return system. I haven’t heard of a restricted return system building up enough pressure at the pump to blow diesel by the pump shaft seal, but I suppose it’s worth checking. Pulled the inspection cover and checked the key. It looked to be indexed and seated in the gear just fine. Went ahead and pulled the pump anyway just to be sure I didn’t mash it. Key is just fine, not mashed or marred anywhere, and the key way on the gear is just fine too. Verified that the key matched the numbers on the side of the pump. The shaft seal looks just fine. There’s some diesely oil on it though, but not just straight diesel. I don’t know a good way to test that seal, and I know the chances of it being bad are slim. I suppose I’ll reinstall the pump, but I’m wondering if I should have it tested. I’d have to ship it off to do that though. Sort of at a loss for the moment.

That makes sense. So a higher pop pressure forces a higher engine load at idle, increasing the longevity of the injector. In your case, at idle with 13% engine load, double the stock load, you’ve essentially increased the life of your injector roughly two fold. When the engine load decreases past the stock 6-7%, the now looser injector will allow the engine to idle faster due to it popping faster and easier, above 800 rpm. My truck idles just under 900 rpm. Curious though, if longevity of the injector in this case is based on engine load at idle, wouldn’t a higher load accelerate injector wear? Because injector wear rate isn’t a constant, would having injectors that idle at a engine load of 13% wear down to the stock 6-7% at a faster rate than the time it takes to wear down from 6-7% down to 0%? Just to clarify, I can’t have my rv275s popped to the same pressures and flow rates matched after they’re tested. Is that what you meant when you said you don’t recommend them anymore? Actually never mind on that middle paragraph. I answered my own question, just didn’t see it at the time.

Okay sounds good. I’ll have them tested and adjusted if necessary.

Interesting, thanks for that information, that pretty much covers what I wanted to know about pop off pressures. Starting to wonder if pressures on mine are too low. So to be clear, if I have these injectors tested, will the pop off pressures for each be provided, or is that gonna be something I have to request? Only had injectors tested once a few years ago and don’t remember if I was given that information. If one or more are found to be too low, because I can’t have these popped to a different pressure, are they worth having rebuilt? Or should I just maybe move on to a different injector being that these aren’t customizable. I don’t really plan on running a tuner on this truck for the moment, I just need it to run properly.

I did the oil cap blow by test when I bought the truck and it has no blow by. Well, not enough to move the oil cap anyway. I was doing some research into pop off pressures last night and it seems like something funny could be going on. It’s almost like the fuel injection timing isn’t quite right. It’s strange though because the running condition is a gradual decline, relative to engine temp, not an instant all the time failure. Leaning toward a stuck injector. I think I’ll pull them out this weekend and have them tested.

Hasn’t thrown any codes. Checked with my friends snap-on scanner.

Hey all, First time posting on the forum, but have used it in the past to fix some of my other trucks issues, some great information on here. I’ve got a problem with my 1998.5, 2500, 4x4, nv4500, 263k miles. Truck is stock with no aftermarket performance mods, and it is unfortunately a 53 block. I bought the truck recently as a back up for my 1997 7.3 as it just ticked over 500k miles and is gonna need a rebuild soon. Three weeks after I bought the truck it began giving me hard starts only after it reached operating temp. I falsely diagnosed this as a fried vp44 pump, given the fact that it still had a factory style lift pump, so I put a reman industrial injection pump on it, a fass drp lift pump, big line kit and a mechanical fuel pressure gauge on the truck. Did not fix the issue. After installing the pumps, I changed my oil and found an extra 1-2 qts of diesel in it as well. So, I bought a set of rv275 hp injectors(only aftermarket performance mod truck has), and crossover tubes. Truck would fire up and idle just fine when it was cold, but began to idle rough when it warmed up, also the rpms would bounce from about 900 to 600 back and forth only going down the road when you popped it out of gear and into neutral like if you were gonna coast to a stop. This got progressively worse to the point where taking your foot out of the throttle from any rpm and shifting to neutral would stall the truck. Got a opinion from a friend who is a diesel mechanic, and he said the hard starts were because of a fried ecm, and the running issues were injector related. Got another ecm and it solved the hard start issue. Still had the same running problems though. I figured I made a mistake when installing the injectors and tubes, and removed them, cleaned them, checked the nozzles, put new orings and copper washers on them and the crossover tubes, reinstalled. Torqued the injection lines first, then injector hold down bolts second. 89 inch lbs. Drove the truck around yesterday and today. Same result, truck still idles rough only once it’s gotten warm, rpm will bounce when going from a load to neutral, and attempts or sometimes manages to stall when going from a load to neutral. Also still getting diesel in my oil. No visible diesel leaks anywhere either. Tried to torque the injectors again thinking maybe they might gotten loose through a couple heat cycles, and it made one difference. Starts up in a bump, and doesn’t smoke excessively on start up or going down the road aside from a little puff of black smoke when shifting into the next gear, but I believe that’s normal. To my knowledge there’s really only three likely places on 24 valves to mix fluids. Injector body cracked, injector seals, and front shaft seal on vp44 which seems pretty uncommon. If that doesn’t change anything I might have to pull the injectors again and have them tested just to rule that out. I’ve replaced injectors on these trucks before with no issues, so I’m not sure what I’ve managed to miss twice. I’m also not sure how to test the front shaft seal on the vp44, and pulling the inspection cover with the engine running seems sketchy. Guy I bought it from doesn’t want to return my calls, starting to wonder if there’s something wrong with the head. Sorry for the novel, any insight would be appreciated. Thanks