1st Generation Dodge Cummins 89-93 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with Rotary Injection Pumps

my cummins is knocking help

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Old 12-24-2013, 11:19 PM
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Default my cummins is knocking help

Ok so I am kinda new to this whole dieseliss thing bought my first Gen cummins had the knock at the time I looked at it and I let my emotions over power logical thinking but I did drive the truck over 150 miles home with no issues idk what it could be cause the truck runs great
 
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Old 12-26-2013, 12:14 AM
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I haven't cracked an injector line yet to test for bad injectors I'm really hoping its not a thrust bearing but the knock kinda comes and goes ill fire it up sometimes and sounds normal turn it off and start it straight back up and the knock is back
 
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Old 12-26-2013, 11:38 AM
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more than likley the bearing if its still runnin strong.....
 
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Old 12-26-2013, 08:02 PM
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What is your oil pressure like? is the knock down low or up in the head somewhere. If at the upper engine (head area), could be a failing or failed injector. Down low,.......well you know. Check the oil for metalic hue or metal flakes. Change the oil and see whats there.
 
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Old 01-02-2014, 10:44 PM
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I can't really tell if its up top or down bottom I'm still using the factory gauge on the dash it takes a Sec when u start it and slowly moves to about the 3 to 4 th notch over usually stays between them two but my last two injectors stay wet and there is black stuff on the hood above them?
 
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Old 01-02-2014, 11:08 PM
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My second gen blew the crush washer on the number 6 injector and spit fuel and soot until I replaced it. It didn't knock, though. Sounded EXACTLY like an exhaust leak (which is what I thought it was until I found the wet injector.
 
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Old 01-03-2014, 11:54 AM
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I wish I new more about diesels that would be a huge help but this is the first one I've ever ownd so I'm kinda Learning as I go I can't pin point exactly where the knock is comn from cause if your over the top it sounds like its up top but if your under it sounds like its down bottom
 
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Old 01-03-2014, 03:27 PM
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Well, I don't think you've spun a bearing. Your oil pressure will either spike (because the bearing blocks the oil journal), fall to nothing (if it's real bad) or go back and forth between the two as the bearing continues to spin. Drain the oil and look for signs of metal dust/shavings/chunks or pull the pan and peek up at the bottom end.

If the valves are way out of adjustment it sounds similar to a knock, but it's pretty distinctive. Maybe you just don't know the difference because you're new. Adjusting the valvetrain is easy and doesn't take that long.
 
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Old 01-03-2014, 04:42 PM
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I've had a couple people say it sounds like a valve but I'm just trying to get a good opinion from people who own or have worked on these trucks its deff not a rod type knocking sound my turbo sucked a dirty filter shut and when I replaced it it quit and sounded fine but when I fired it back up it started doin it again I'm pretty good with gassers but this is a whole different world to me I app all the input from u guys
 
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Old 01-03-2014, 07:08 PM
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Good Lord, talk about a run-on sentence.............
It may be a failing injector, excessive carbon build-up in a cylinder, or maybe even a noisey wrist pin. Hard to say really without hearing it.
 


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