12 Valve 2nd Gen Dodge Cummins 94-98 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with P7100 Injection Pumps

I Think My P Pump Took a Dump

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Old Dec 7, 2008 | 04:29 PM
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Default I Think My P Pump Took a Dump

ok here it is was popping at all rpms hot or cold, #5 cylinder running cold all cylinders have good compression, also have a loud tick comming from p pump, and will not return to idel quickly, (acts like a gas engine with a vacuum leak) also truck has new stage 2 injectors in it, any ideas???
 
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Old Dec 7, 2008 | 04:55 PM
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god damn sorry wish i could help on this one
 
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Old Dec 7, 2008 | 05:02 PM
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yeah this sucks
 
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Old Dec 7, 2008 | 05:10 PM
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i know mine was popiing at 3000RPM untill i got intake and exhaust valve springs but this might be a different perdicament
 
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Old Dec 7, 2008 | 06:51 PM
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double check the connections on each of the fuel lines and make sure youre not sucking air, im not 100 percent convinced that its your pump but it is wierd for one cylinder to not be firing, maybe a stuck injector, i know you said they were new but maybe youve got a bad one and if it is stuck, it could be forcing a pressure build up which maybe causing the ticking.
 
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Old Dec 7, 2008 | 07:17 PM
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P pump failures are unlikely. How many miles on it?
 
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Old Dec 7, 2008 | 07:37 PM
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Yeah, prolly not the pump... more likely an injector. I have over 300K on my P-Pump and its still running fine... All together with all 3 trucks, well over 1 million miles and no problems with them.
 
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Old Dec 7, 2008 | 07:45 PM
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Might want to try moving #5 injector to a different cylinder and see if the dead cylinder follows it. that will rule out one or the other.
 
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Old Dec 7, 2008 | 08:41 PM
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swapped injectors around and then also checkedall of the delivery valves and the carriers all looked fine, allthough my fuel pressure has gone from a steady17 psi, to jumping between 10 and 30 psi, pulled and pressure checked relieif valve and its ok, rigged up a pressure gauge for testing each port individualy, useing an old injector, extra injector line, and a high pressure gauge, # 5 is not reaching full pressure looks like the inner piston assembly is messed up, it dosent reach full pressure to open the injector, and the weird part is how the throttle stays at hi rpm and then suddenly falls off and then dies.

hey can i remove the carier part by removing the 2 nuts and just replace it while still on the truck and if so can you replace the little piston as well???? with out a major tear down, thanks guys, oh and does anybody have a pump tear down guide as well, they mite be willing to share??

and this all started after the truck sat for about a week while i was out of town,
oh and 295, 000 miles,

looks like the pressure from # 5 plunger if back feeding into the main fuel galley, looks like something failed or cracked, inside, any ideas??
if i can tear into it on the truck i will take pics so we can post them.
 

Last edited by gone ropin; Dec 7, 2008 at 10:25 PM.
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Old Dec 8, 2008 | 10:06 PM
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ok here it is, the plunger barrel for #5 is cracked, so now off with the pump and to the performance shop
 
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