Today while towing my 10k fifth wheel up a medium grade on a moderate day (82deg) 58 mph in high gear, I heard a knock than engine shut down. pulled over , re started, good oil pressure, no knock, no smoke out back or under hood, temp came down to normal. creeped home. let it cool restarted sounds normal. some blowby out of tube. any thoughts. 1997 2500 auto 156'000 miles,owned since new, no guages beside stock, 100 fuel plate for many years, driven like an old lady.

 

My bet is an injection pump plunger or bore is warped and stuck.
The knock is pretty scary.
I put up with the same problem for years before getting a new rebuilt pump.
It is pump heat related and will eventually start doing it more and more. Mine most always did it on uphills.
I found a bandaid fix to the problem is to keep your tank most of the way full, more fuel to cool the pump.
Never tried it but have heard when the problem starts getting really bad you can get going again by pouring water over the injection pump.

 

If the plunger stuck, wouldn't you have a miss and the throttle would stay where its at, instead of dying, seeing as the rack can't move at that point?

 

Not sure on the stuck rack.
Mine would die unless you kept your foot on the throttle but would knock bad.
It was obvious when the pump was torn down what had been going on, the bore was all scored up.

 

My '95 would be bad about that during the summer months(100f+ for days). The first time i heard it I thought I had an injector stick open or a head gasket let go. Correct me if i'm wrong but I thought only the 94-95 models had ip problems.

 

Thanks guys, runs as if nothing happened. I don't know If I should tear into the pump or wait for it to happen again.

 

Wish you had gauges, then you could tell us what kind of EGT's were you seeing when it happened.

Infidel, do you recall what your EGT's were when yours originally knocked.

 

Need gauges, figured if I babied it I would be alright.

 

Quote:

Correct me if i'm wrong but I thought only the 94-95 models had ip problems

I've heard reports of all years having the same problem but '94-'95 are more frequent.

All my gauge numbers including fuel pressure were always fine when it happened, in fact that's why I installed a fuel pressure gauge 15 years ago.
Egts were under 1000.

Normally when it happened I could pull over and let it cool for 5 minutes and it would run fine, most times for hundreds of miles. Sometimes it went over a year between occurrences even in hot situations where I would expect it to happen.
I was always careful to keep my tank at least half full though.

Last straw was when I had to pick up my daughter at the airport and it started knocking really bad and wouldn't pull out of it even after cooling for an hour. Obviously my daughter was ticked off at my not being there when her plane landed. Middle of nowhere with no phone or cell service.
When I finally got to the airport I fully intended to just leave the truck there to be towed and rent a car but it started right up and ran fine for the 180 mile trip home.
I didn't want to deal with that stress again so finally replaced the IP. That was four years ago with no more problems.

 

I wonder if we are going to see more of this with the new diesel formulation that came out a few years ago. Sounds like a lubricity failure to me. Tolerances in the IP are extremely tight as I recall.

 

At work we overhauled a 5.9 and had the pump rebuilt at the same time. When I picked up the pump the guy told me that the barrels and plungers were trashed,and this was with a pump that had no apparent problems. He told me that cummins and bosch say that you must run an additive if you use ulsd,and that they discontinued the p7100 pump so once the new ones are gone thats it.