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

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Old Nov 1, 2010 | 11:18 PM
  #11  
bullrider96's Avatar
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are you sure you dont got no air in the lines does it like pop start with white smoke
 
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Old Nov 2, 2010 | 07:11 AM
  #12  
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^oh this is also a good point.. try bleedng the lines
 
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Old Nov 2, 2010 | 08:38 PM
  #13  
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i guess i havent bleed the lines how do u do that? and how do u adjust the idle

---AutoMerged DoublePost---

how do u bleed the lines and set the idle
 

Last edited by corey mcintosh; Nov 2, 2010 at 08:38 PM. Reason: Automerged Doublepost
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Old Nov 2, 2010 | 09:30 PM
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I think with the 12v's you just crack the injector lines and turn over the motor or use the pressurization bulb. Idle I'm not so sure; think there is an idle screw in the afc? Or around it?
 
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Old Nov 2, 2010 | 10:18 PM
  #15  
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Originally Posted by 85_305
I think with the 12v's you just crack the injector lines and turn over the motor or use the pressurization bulb. Idle I'm not so sure; think there is an idle screw in the afc? Or around it?


WHAT?

This is not accurate info.

The "pressurization bulb"??? Idle screw on the AFC???

Even after changing the fuel filter on a 12 V you rarely need to bleed air out of the injection lines. You usually can get a 12V started and the air will gradually work its way out of the system. I have changed many fuel filters on both 12Vs and 24vs over the last 8 years and Ive never had to bleed the lines at the injectors.




Corey,

First - from the fuel pressure numbers you gave - your fuel pressure is somewhat low. iirc, it should be 22 psi min at idle and increase to around 32-34 psi under full load. It looks to me like you might need a new lift pump. How many miles are on the stock pump? You do not need an electric pump fass or duramax. The oem lift pump will support 450+ hp.

Heres a how-to for lift pump replacement:

Diesel Ram lift pump replacement



Again, how many miles are on the truck? You say you "turned the pump up" - meaning what??

You injector pump may have some wear. Its fairly normal to have to give it a little pedal to get it started. Bumping your idle up a bit may help (you should be @ 750+ rpm in gear with ac on). Heres how-to bump your base idle if you dont know how:

Ram Diesel Problems



It might be worth changing your fuel filter and cleaning/checking the pre-filter. Heres a how-to on that:

Fuel Pre-Filter Cleaning on Ram/Cummins

Another possibility is that you may be losing prime from either dry rotted fuel lines (have the rubber lines ever been changed?) or from the fuel heater (this is a very common problem as well).


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Good luck.
 

Last edited by Dr. Evil; Nov 3, 2010 at 12:56 AM.
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Old Nov 2, 2010 | 10:21 PM
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Oops guess cracking the injectors lines is a 7.3 thing. my bad.
 
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Old Nov 2, 2010 | 10:36 PM
  #17  
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Bleeding lines to the injectors is sometimes needed on a 12V but it will generally start and work the air out of the system after a few minutes.
 
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Old Nov 2, 2010 | 10:39 PM
  #18  
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And why is that? Why can the 12v's self bleed but a 7.3 will run like ******** if they aren't manually bled?
 
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Old Nov 2, 2010 | 10:49 PM
  #19  
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I dont know the first thing about a 7.3 and its way off topic for this thread.
 
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Old Nov 2, 2010 | 10:56 PM
  #20  
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Originally Posted by 85_305
fass pumps are a waste of money on 12v's. 12v's dont need crazy hi fuel pressure like 24v's do.
UMMM hey there you are wrong the 12v takes 35 psi at wot
the 24v is max of 17
get your facts straight before spilling them
and as for the fass system it is a great addition to the truck or an airdog
 
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