Archived loud knock in injector pump.

[jfrost]

Never had any problems before, but today on a long road trip all of a sudden the truck started shuddering and a loud knock developed and the truck stopped running. Waited a few minutes and checked the fuel solonoid and it was pulled up all the way and all fuel lines, filter etc. are tight with no leaks. It did this about 6 or so times today. I had to keep driving and it kept surging. IT would start to die and then come back to life and knock would go away. The knock is very loud and sounds like its coming from the injector pump. I got it home and for the last approx 2 hours it ran better, but i was being really really gentle with the throttle. I am wondering if the knock results from the pump running dry for a few seconds.

I don't know what to do. Do I take it to the dealer or to a cummins shop or what? The only thing different i have done lately is switch from a Napa fuel filter to a Fleetguard one. But this should not be a problem. I think I have a major problem here. Any advice would be greatly appreciated. Thank You.

 

[illflem]

Sounds like a sticking delivery valve or injector. Sometimes a double dose of diesel additive will clear it up. Otherwise find a competent non-dealer diesel mechcanic, hopefully Bosch certified.

 

[Evan A. Beck]

Had a '95 in the shop that was doing the same thing. Found a delivery valve sping to be broken, and had sent metal fragments thoughout the pump. A complete rebuild fixed it right up. Truck had 95K on it.

 

[jfrost]

Thanks for the suggestions. My question now is for the man that said he had his pump rebuilt. Did you take the whole truck to the rebuild shop or did you take the pump off the engine and take it to them? Also where did you have the work done, and how much did a rebuild cost if you don't mind me asking. Thanks.

 

[illflem]

Several years ago a friend had his P7100 replaced with a rebuilt pump by Cummins NW in Yakima WA. It only took a few hours and cost him $1100 total with his pump in exchange.

 

[Evan A. Beck]

I took the pump off at our shop, and then sent it out to be rebuilt. They went through the entire pump, and put it on a flowbench to check the sylinder balance and injection quantity. Book time to R&R the pump is 5 hours, and the rebuild can vary between $300 and $700, depending how much is busted. Rebuilding the pump is usually a more cost effective wayt o do it, but sometimes you can find a rebuilt pump to swap right in. New pumps are around $2,500, and rebuilt ones are around $1,400.