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

12 valve popping..?

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Old 04-03-2011, 11:45 PM
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Default 12 valve popping..?

alrighty so im just kinda wondering if any other trucks do this or what the problem might be..

when im cruzing along in third or fourth gear at about 2k rpm and then put it to the floor it goes for a second then pops and lets out a big puff of smoke.. or if im in neutral and wick the throttle it revs up then pops and smokes then keep goin... im not sure what it could be.. a surge or lack of fuel maybe?

any thoughts or ideas would be helpful!
 
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Old 04-03-2011, 11:47 PM
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timing or fuel pressure. do you know what either are?
 
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Old 04-03-2011, 11:51 PM
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not sure about the fuel pressure, and i havent messed with the timing... i guess it could have slipped.. if it slips would it advance or retard?
 
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Old 04-04-2011, 08:42 AM
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if it slips it will retard and from what you are saying thats what it sounds like.
 
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Old 04-04-2011, 04:37 PM
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either that or the 7x12? injectors are draining your fuel supply IF it is all stock...
 
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Old 04-04-2011, 09:14 PM
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I would start with checking the timing first. Sounds to me like thats it. But could very well be fuel pressure issue.
 
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Old 04-05-2011, 12:05 AM
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super hot egts or tons of unburnt fuel cause that breaking up sounds your talking about, low timing is normally the cause of the soaring egts and breaking up. i know these trucks are pretty common to slip timing so to me that sounds like your problem, id put my money on it.
 
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Old 04-06-2011, 02:47 AM
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Its not amount of fuel that causes it. Its the injection time in relevance as to where the piston is. A stock truck can have this issue when cold if the timing has slipped some over time.
 
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Old 04-06-2011, 03:01 AM
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These are all good posts. You'r having some timing issues.
 
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Old 04-07-2011, 11:57 PM
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sweet deal well not really but thanks for the help fellas!! looks like i need to get on that! i have read about how to time it makes sense. ohh and does anyone know why they lose time? i understand how it happens the pump gear is on a tapered shaft and has no key way so it can spin but is there any factors that might cause this?

and again thanks alot!!
 


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