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

98 3500 Dodge 12 Valve question

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Old May 30, 2011 | 07:46 PM
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97powerstroke4X4's Avatar
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Default 98 3500 Dodge 12 Valve question

I have a 98 Dodge 3500. Only mod is straight piped. The truck idles fine when it is in park but if u turn the wheels or put it in gear it gets really rough and wants to die. Any help is greatly appreciated.
 
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Old May 30, 2011 | 08:03 PM
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94 12valve's Avatar
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what is the idle speed when you put it in gear? sounds like you need to bump it up a little
 
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Old May 30, 2011 | 08:42 PM
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In park it is like 700-800. In gear 500 or lower
 
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Old May 30, 2011 | 08:45 PM
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yeah that sounds to low idle. when mine was that low it would die if you let off the gas to fast. bump idle and no more problems
 
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Old May 30, 2011 | 08:49 PM
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My bad it is kinda slow not real fast. Slower than my 02 F-250

---AutoMerged DoublePost---

Nevermind what i just said
 

Last edited by 97powerstroke4X4; May 30, 2011 at 08:49 PM. Reason: Automerged Doublepost
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Old May 30, 2011 | 09:54 PM
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It shouldn't drop that much just from turning the wheel or putting it in gear. 700 rpm ,no load, is spot on. Did you ever replace the lift pump? When there on their way out they drop PSI at idle, putting it into gear should only drop about 50 to 100 RPM, but its sometimes enough to drop fuel PSI down to almost nothing. Check for bubbles in the fuel return line too, change RPM when checking. If bubbles you have other issues than a low idle. All this is assuming you already changed your fuel filter and have no issues with the fuel itself. Hope this helped..
 
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Old May 31, 2011 | 11:46 AM
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Idle should be 750-800 in gear with the AC on.
 
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Old May 31, 2011 | 08:15 PM
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It is close to that but drops when i put it in gear. it doesnt do it every time though.
 
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Old May 31, 2011 | 08:22 PM
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READ the post above again. 750-800 rpm IN GEAR
 
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Old May 31, 2011 | 08:33 PM
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So sorry!!! it is about 500 when it is in gear and it drops. READ THE POSTS ABOVE
 
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