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 

1 hour ago, MikeH said:

I think that's the first time I've heard of the injection pump leaking into the timing cover.

 

VP44 are know to possibly leaking after 20 PSI some can make a full 30 PSI without it blowing out and some barely 25 PSI and its leaking.  Just to clarify optimal pressure is between 14 to 20 PSI. The only time I've seen seal leaks is above 20 PSI.

17 minutes ago, Mopar1973Man said:

The only time I've seen seal leaks is above 20 PSI

Outside the race crowd though (they can run insane boost pump pressures) I still think this is the first for me. I wonder if his FASS is set too high or he just got a bum seal?

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. 

29 minutes ago, CodyBeasom said:

 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. 

Yours is the first for me. Let us know how Industrial Injection treats you on this problem. They're on my radar should I ever need a new pump. I'm not saying it's their fault but would like to know their response.

BTW, can you get your fuel pressure confirmed on another gauge? It occurred to me that your gauge might be off and your pressure is way high. Just a thought. Again, good luck

Edited August 29, 20213 yr by MikeH

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. 

15 hours ago, MikeH said:

Yours is the first for me. Let us know how Industrial Injection treats you on this problem.

 

Too keep all rebuilders honest. Make sure to make a identifying mark on the pump (make a domino mark, paint marker, etc. Then make photos of all the numbers and the pump itself. Then when they make a claim to void the warranty. Then tell them to send you a picture back of the pump. If it does not match your numbers, ID mark, etc. then you know they are trying to cheat. This method has help a few beat the void warranty claim problems. 

Edited August 30, 20213 yr by Mopar1973Man

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. 

Edited August 30, 20213 yr by CodyBeasom

3 hours ago, CodyBeasom said:

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.

That's what I was hoping to hear. I've never dealt with these guys but they're still on the top of my list when I need a new pump.

On 8/30/2021 at 10:04 AM, Mopar1973Man said:

 

Too keep all rebuilders honest. Make sure to make a identifying mark on the pump (make a domino mark, paint marker, etc. Then make photos of all the numbers and the pump itself. Then when they make a claim to void the warranty. Then tell them to send you a picture back of the pump. If it does not match your numbers, ID mark, etc. then you know they are trying to cheat. This method has help a few beat the void warranty claim problems. 

I do some random markings on engine parts if I have them machined, especially on some older stuff that people want. I did it on my head too when doing hg, valve guides, just to be sure they don't say oh it's junk and cracked. I trust my shop for the most part but you just never know. Seen people get screwed this way before.

16 hours ago, Dieselfuture said:

I did it on my head too when doing hg, valve guides, just to be sure they don't say oh it's junk and cracked.

I've had a shop just take too much off a set of Honda Goldwing head and now the motorcycle no longer runs cool and over heats (too high of compression).

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. 

Interesting. Yeah get back again when you have the pump back in and tell us what you got going on. 

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.