Here is the background- 94 CTD auto, 213,000 miles on it. Serviced regular, fuel filter changed within last 3000 miles, clean, good fuel, stock engine except for 75 hp injectors (30,000+ miles ago, trouble free), no current issues.
I drove 120 miles (one way), pulling a gooseneck horse trailer, to pick up two ponies for a friend. On the trip there, after about 90 miles, I had a few moments where the truck seemed to be pulling hard- I thought that I might have a brake dragging on the trailer. Stopped, no more issues for about 40 miles. At this time, the truck started slowing down; I could press the accelerator, with no RPM change. Engine quit, so I pulled to the side of the road. I sat for a minute, thinking things through, and then tried starting it. It would try and fire, so it was getting some fuel. After a couple of attempts, it started, but idled a little rough; it then cleared out, and ran fine. I knew that I was having an issue, but I didn't like where we were stopped, so we kept going, to see if we could find a better place, as well as try and determine the parameters of what was happening. Oil pressure was fine, and so was temp, fuel level, and ammeter. This was still on the same tank of fuel that I had driven 130 miles.
After another 20 miles, it quit again. Same thing- this time, though, it took longer to get it to start, and once started, it ran rough, then, as if a switch was pushed, it ran perfect. I didn't make it 2 miles the next time. So, we called for help- my father came and pulled the horse trailer home. My truck is parked and safe at a gas station, and we are going back tomorrow to get it.
Here is what I have done so far in the way of investigation. I drained the fuel filter, which did nothing. I can prime the lift pump, filling the drain in the fuel filter in 4 or 5 pumps. The fuel tank is a little over half full. The fuel shutoff appears to be working, although it could still be the culprit. I did cycle it, checking it with the key off and on- it was down when off, and up when keyed on. And, it shuts the truck off fine, when it runs. I did check it when it quit- I didn't turn the key off after the engine shut off, and I then checked the shutoff- it was in the full up position, and I couldn't pull it down at all, or push it up any. Turn the key off, and it was down.
At this point, I think it is fuel delivery, but with no break in the system- I never had to bleed anything to get it running again- it just would fire and take off. I am assuming that it may be a blockage, perhaps in the tank or in the fuel heater/screen. To my knowledge, the heater/screen has never been serviced. I have been meaning to, but you know how that is- it isn't an emergency until it's an emergency.
So, what are your thoughts? Anyone with a similar circumstance? It doesn't appear to be injection pump or injectors. When it does run, it is at full power, and no miss. I think it is somewhere between the tank and the fuel shut off, but what I don't know much about is the return system- can a problem in the return system cause this?
As always, I'm learning. Any input you can give would help me get the guy running again. We are going over in the morning and loading it on a gooseneck trailer. It runs fine at times, so I don't think I will have any problem getting it up on the trailer.
Mark

 

Sounds exactly like what both my trucks did when the injection pump plunger and bores warped.
This problem is fairly common with '94 and '95, pump rebuild or exchange is the only fix.
It might not do it again for a long time, mine would go at least six months sometimes.
Easy way to tell if warp is the problem is to pour some cold water on the injection pump next time it happens.
If it pulls out of it there's your problem.

Problem is heat related, keeping your tank on the full side will provide a bigger pool of fuel to cool the pump. This is what got me though for several years till I finally broke down and bought a rebuilt here> http://www.usdieselparts.com/index.c...-dodge-59l.cfm

 

Infidel, what caused that? The current pump was replaced about 100,000 miles ago.

 

I read your complete post..It sure seems similar problem I had with my 95...The truck would shutdown on the highway...Sometimes in 20 miles...sometimes in 200 miles....In my situation...It was something hanging up in the IP...Once I replaced it..the problem was fixed...There are problems with the 94 and 95 IP doing this...

But before replacing a IP...do extensive troubleshooting...Maybe some of the other guys will have some additional input..

 

It isn't the original pump- a Cummins shop replaced it for the previous owner. The original pump wasn't rebuilt, but replaced with a rebuilt one. I don't know what to assume- is it better than the original pump, or do the same problems exist even though it was rebuilt?

 

Yes...I seen where your coming from Mark...Bill posted just before me...

Time for some troubleshooting...Checking your IP pressure is the first step..Making sure your OF valve is ok and your lines are not bleeding air...Got to run a lot of tests first..

 

What the F, those pumps are over a grand for trucks 20 years old! is that normal??? I only paid $2,000 for the entire truck as its so old!

 

I've also experienced this on a couple of 94 or 95 trucks, and will add that when the loss of acceleration would occur, it would also be accompanied by a weird chattering sound from the injector pump. Did you notice any weird sounds like that when it was acting up?

 

No wierd sounds. It happened a total of 7 times before parking it, and I never did hear sounds. I would hear a stutter when starting it up, and it was beginning to fire, as the injectors were finally getting fuel. But, no different than the sounds during a real cold start- nothing that caught my attention, or sounded abnormal. I listen pretty closely.

So far, all three responses are clearly looking at the injection pump- I assume that I should assume the worse? I'm a realist- I know that things are not usually as simple as we would like- but, I do want to check things when I get it home, and that will have to start with the simpler things.

 

Price any injection pump- they aren't cheap. Age of the truck has nothing to do with it, but necessity and complexity. I'd rather pay the money for a 7100 than I would a VP44.

 

Mine would only shut down on the highway...Just like the fuel got cutoff...Never was able to have it shutdown driving in the city..

On one 700 mile trip..Truck shutdown 12 times...Coming back only shutdown once....Next trip of 25 miles...It quit 6 times..It was so random.

No one is sure why the orginal 94 and 95 pumps did this..Heard it could be the govenor hanging up..It was some sort of defect that came out of factory..What ever they do to the rebuilds,fixes this problem..

But do your checks including the pressure test,before buying a IP...

Oh...almost forgot another test...Wire up your IP startup switch...Just to elimate that it's not cutting out...or falling during highway driving..

 

We went over and picked the truck up this morning. We towed it with my dads F350/V-10- with a 6 speed manual and 4.30 gears, it pulled admirably. We had to cross the Blue Ridge mountains on I64, and never got below 5th gear.
We pulled it home on a gooseneck trailer, so we were depending on the truck starting up and being able to drive it up on the trailer. It started fine, and I had no issues loading or unloading it. Now that it's home, I will start looking at some of the more obvious stuff. If it is an injection pump, there is a Mack shop about 40 miles away that can bench test and rebuild it. I will take them my pump and injectors. Hopefully, I don't get to that. I just ordered a shutoff, relay, and preheater screen from Geno's. Probably needs the stuff, anyway.
I think I will drive it locally, and see if it will act up.

 

Good advice above about driving it with the shutdown solenoid arm wired up. If you are able, installing a temporary fuel pressure gauge might also be helpful just to make sure pressure isn't disappearing to make it act up.

 

My 3500 started acting up when it was still under warranty.
On one trip down I-5 in Oregon it cut out 16 times and I stopped at four dealers for help.
None wanted to blame the IP.
Last time it cut out I called for free towing that came with the warranty.
By the time the tow truck got there it had cooled down enough that it drove fine about 75 miles to the closest dealer.
This dealer did everything to it: retimed, new lift pump, new overflow valve tilted bed to check the tank filter, replaced the main filter for the 5th time in 250 miles.
Still didn't want to blame the IP.
I left there and it didn't act up again for over 2500 miles, thought it was cured.

It wasn't and by this time the warranty was up.
This problem was the reason I broke down and bought a computer, paid the money and joined TDR.
No one there had the answer either. It wasn't till I talked to Piers of PDR diesel that I found out about the warping and finally replaced the pump.
It had been five years since the first time it happened.

Sometimes it would knock really bad but most times what happened is it took full throttle just to idle. It always ran fine again after it sat, the longer the better.

 

While I was testing my old pump....I had it rev out the motor..on the highway when I placed the trans in neutal..It only happened once......