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

shaking at idle

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  #1  
Old 06-24-2011, 01:57 PM
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Default shaking at idle

today while I was reworking my cylinder head, I found #5 and #6 exhaust valve only holding 10 Hg, so I reworked the seats and they are back to 25 Hg.

here are some pics of my rebuild

the pictures with the exhaust valve out, that is after I reworked it (on a peterson 25 guide and seat machine)

the picture with the piston, this was the worst of them(just alot of carbon build up)
 
Attached Thumbnails shaking at idle-bad-vacuum-test-2.jpg   shaking at idle-piston.jpg  

Last edited by cummins_guy; 06-24-2011 at 01:59 PM.
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Old 06-24-2011, 02:02 PM
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here is before and after pics
 
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Old 06-29-2011, 04:19 PM
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when you say shaking at idle are you talking about like sitting at a stop light and all of the sudden your truck starts to shake a little? cus i have that problem every now and then some times worse then others
 
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Old 06-29-2011, 05:51 PM
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Good work Cummins Guy, very nice!
 
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Old 06-29-2011, 06:57 PM
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Originally Posted by t-bone117yamaha
when you say shaking at idle are you talking about like sitting at a stop light and all of the sudden your truck starts to shake a little? cus i have that problem every now and then some times worse then others
If the idle rpms drop too far these baby's will shake like a stripper needing to make a rent payment.Rocky
 
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Old 06-30-2011, 02:25 AM
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Originally Posted by t-bone117yamaha
when you say shaking at idle are you talking about like sitting at a stop light and all of the sudden your truck starts to shake a little? cus i have that problem every now and then some times worse then others
I have that same weird shake when i come to a stop at a light..... sometimes its worse than others also. Its got me confused.
 
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Old 06-30-2011, 10:54 AM
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so is it something that i should look into and maybe turn up the idle a bit? or is it just something that wont really make a difference other then stopping a little bit of shaking every now and then? thanks
Tanner
 
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Old 06-30-2011, 12:50 PM
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What's your timing set at? If you increase the timing it will shake the engine a bit more. Although not sporadically... Is your KSB cycling on and off?
 
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Old 06-30-2011, 10:03 PM
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mine did the same thing. almost like a nasty lope sometimes. especially after getting into it hard for a long shot. i some things i thought of are maybe timing, possible air in fuel issue, or idle too low. i turned the pump up some more to bring my idle up 100 rpm and it seems to be doing better now. i just havent had time to look into messing with my timing yet since its advance 1/8" to the head.
 
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Old 06-30-2011, 11:22 PM
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Its probably a injector with a bad pop... Clean and pop test your injectors...
 


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