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

injector pump spazing out after a couple miles

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Old 08-23-2012, 09:41 PM
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Default injector pump spazing out after a couple miles

Hey fellas new to the diesel world just put a cummins in a F350 and am having some trouble I used EVERYTHING from the dodge truck and when i run the thing in the afternoon it starts missing real bad and i have no throttle control. Whatever rpm im at when the pump starts missing it stays at that rpm until the pump releases and then you hear a plunger pop sound and it starts running normal again.Idrive the thing all over in the morning and its fine has all the power in the world but the heat in the pm is its enemy for now. Ihave put alot of time in this project and this seems to be the only problem but its a problem nobody can explain to me. Ive replaced the lift pump and it didnt do anything so im trying to avoid coffing up 1200 for a pump any advice would be greatly appreciated.
 
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Old 08-24-2012, 03:52 AM
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i have 160 ppump i will sell ya, pump has recently been rebuilt.
 
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Old 08-24-2012, 05:35 AM
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Check the fuel pressure at the pump, the OFV may be worn out and bypassing fuel causing low pressure and making the pump run dry....
 
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Old 08-26-2012, 08:18 AM
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I still have to get some gauges thanks for the info Walstrom1. how much you askin on the pump Cptstb?
 
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Old 08-26-2012, 08:30 AM
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Sounds like the rack is sticking or its a gov problem. Im leaning toward the rack sticking. Which if thats happening then there is a good chance that the delivery valves are also sticky. Did the engine sit for a long time before you did the swap?

Sent with a Droid RAZR in one hand and 14,000 volts in the other.
 
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Old 08-26-2012, 09:20 PM
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I dont think the truck sat very long I had to jump it to load it on the trailer but it fired up no problem I think the problem is that they put a cheap electric fuel pump after the lift pump went out and I dont know how long they ran it like that I guess runing low pressure isnt very good for the inj pump. I still have plenty to do while I save up just got my high pinion 60 king pin front ready to go in. Just sucks was only able to drive it about a week after all that work.
 
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Old 09-24-2012, 09:56 PM
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Ok I replaced the regulator on the back of the pump and put in some gauges I have 28psi at an idle and 30 to 40 when on the throttle untill pump goes nuts then it drops down to 20psi . How can I tell if its the rack sticking or the gov?
 
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Old 09-25-2012, 09:13 AM
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What exactly did you replace? With the pressure dropping like that it sounds like a lift pump or ofv

Sent with a Droid RAZR in one hand and 14,000 volts in the other.
 
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Old 09-25-2012, 07:49 PM
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I replaced the butterfly bolt for the return line on the inj pump with a torktec regulator.Ive also replaced the lift pump. Dont really know what you mean by ofv still learning.When the pump starts acting up the pressure drops then the pump makes a sound like pulling a plunger off something POP and returns to normal with good psi. I can cool the pump with water and it helps alot. Can you fix pump problems with a oring kit or not and how much of a pain is it?
 
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Old 09-26-2012, 12:56 AM
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i really think you should pull the pump and have it benched just to be safe would hate for it to blow up on ya. if the pump has a problem most likly it will take more then an oring kit to fix it.
 
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