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

Fuel Pressure Question

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Old Mar 5, 2009 | 10:38 PM
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dodger-26's Avatar
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So i recently installed the GlowShift triple gauge pillar kit in my 94 12 valve the have noticed the fuel pressure acting weird. When idling it bounces from 16 to 19 psi...Surging from the cam lobe??? and then when i begin reving up with no load i get around 1300 rpm and the psi is about 24 then the psi starts droppin and ends up back down around 16 psi when i get up to 2000 rpm. Is this becasue of the lift pump goin out on me, gauge problem, the result of sliding my stock plate all the way back, the overflow, or something different all together???? Any help is greatly appreciated.

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The truck is used mostly for haulin racecars and horses around the state.
Thanks again
 

Last edited by dodger-26; Mar 5, 2009 at 10:38 PM. Reason: Automerged Doublepost
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Old Mar 5, 2009 | 11:00 PM
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put an inline valve on it to handle the spiks or you will be replacing guages monthly
 
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Old Mar 5, 2009 | 11:02 PM
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is this a gage that keeps fuel out of the cab or is it like a oil line to a pressure gage
 
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Old Mar 5, 2009 | 11:11 PM
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It's an electric pressure sender that sends a ground signal through a wire to the gauge in my cab. i've tapped it into the Banjo bolt going in the side of the injector pump, where i understood was the best place to put it via another thread. Where would i put an inline sender? and is the placement causing the spiking and low reading??
 
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Old Mar 5, 2009 | 11:34 PM
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not a sender a shut off and barely crack it, first mistake was the electronic, a 12v will kill an electrical sender fast with the pressure spikes the p-7100 will throw at it,
 
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Old Mar 5, 2009 | 11:38 PM
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so what do you suggest i replace the set up with and again is it just the sender/gauge that is giving me the bad readings or do i have a bigger problem???
 
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Old Mar 5, 2009 | 11:41 PM
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no problems that i can think of with the truck at all, mine did it as well with the electric till it blew threw the sendor a week later, get a good mechanical guage and an isolator then you shouldnt have a problem, you can still use yours till it goes out, you need the nedle valve regardless of which way you choose
 
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Old Mar 5, 2009 | 11:42 PM
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this is the best place to put it and the best way to do it
 
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Old Mar 5, 2009 | 11:51 PM
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where can i get this needle valve??? and i would like to keep the electrical because it matches my boost and pyro GlowShift doesn't offer a mechanical gauge...so will the electrical sender work if i get the valve?

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thats where i put it just i placed my sender right in the end of my banjo bolt
 

Last edited by dodger-26; Mar 5, 2009 at 11:51 PM. Reason: Automerged Doublepost
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Old Mar 5, 2009 | 11:53 PM
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you can get the valve at any napa, autoparts store, hardware store, any place that sells compression and flaired fitting, pipe fittings, with the needle valve it will prolonge the life of the sender but 12v's are hard on electrical senders no matter what you do, the valve will eliminate most of the high pressure spikes
 
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