Chevy/GMC 6.2L and 6.5L Discussion of Chevy and GMC Trucks with 6.2L and 6.5L Diesel Engines

Erratic idle & rough start

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Old Aug 29, 2012 | 03:49 PM
  #11  
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I would'nt worry about the cylnder balance faults as they could have shown up due to it running poorly, have you treid another PMD yet??? this is where I would start they are known to make the Idle jump when bad...
 
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Old Aug 30, 2012 | 03:01 AM
  #12  
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im thinking maybe the crankshaft position sensor is going bad
or it has a bad ground sonewhere in that circuit
 
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Old Aug 30, 2012 | 07:12 PM
  #13  
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I had a thought of the cps or a ground, going to check the grounds and see if i'm missing counts off the cps.

Today I did the KOKO TDCO relearn and came up with a couple things. Immediately after staring it, desired and actual timing came to within 1*, which I read is what it's supposed to be. The only thing is after it learning for a couple seconds, TDCO goes to 2.49 and I get the TDCO DTC. I took a look at the pump itself to see how it's indexed, and it looks a little turned towards the driver's side. I'm going to move it back so that the solenoid is straight up and down and try it again.

Thanks for the ideas guys, keep em coming.
 
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Old Aug 31, 2012 | 02:52 AM
  #14  
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i thought that the IP being timed slightly to the drivers side is desireable??? like say.... 1/16 -1/8 inch??? or am i wrong?

with my 6.5, i had to time it about 1/8 to drivers side. with my replacement 6.2, i had to time it dead center. where should it be?
 
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Old Aug 31, 2012 | 06:50 PM
  #15  
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That's what I've read too. I don't know if maybe mine is too far. I've read that for stock timing the solenoid should be straight up. I'm going to set it there and retry the TDCO relearn so I know exactly where I'm at.
 
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Old Sep 2, 2012 | 08:00 PM
  #16  
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Ok, so took a look at the truck for a while today. I rotated the IP to the passenger's side to get the solenoid vertical. Tried the KOKO TDCO relearn, same P1214 code as well as a new P0216. I have a new crank sensor ready to go in, just didn't get a chance to get to it today. If this doesn't work, I'll be looking to go with a new PMD. Can't find anyone around with a spare one to test unfortunately.
 
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Old Sep 6, 2012 | 09:35 PM
  #17  
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Put the new crank sensor in today, same issue with the P1214, but the intermittent P0216 seems to have gone away. Going to be looking at a new PMD unless anyone has any other ideas. Thanks again.

---AutoMerged DoublePost---

Also, another thing I noticed is that with the increase in RPMs, there is a corresponding increase in desired timing (from 5 to 8). Also, Injector close time was going between 2.0 and 2.1 ms, which from what I understand is high?
 

Last edited by daveO; Sep 6, 2012 at 09:35 PM. Reason: Automerged Doublepost
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Old Sep 7, 2012 | 02:42 AM
  #18  
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how many miles on the engine? something sticking out in my mind is the timing chain. Maybe there is a little slop in it, causing the computer to reading the timing as varying. ???
 
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Old Sep 7, 2012 | 08:52 AM
  #19  
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Engine has 184k on it. I thought of the timing chain as well, but would that cause the tdc offset DTC?
 
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Old Sep 30, 2012 | 07:34 PM
  #20  
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So tired a new PMD with a remote mount cooler, same issue. I think I'm going to pull the front cover off and check the chain and timing marks.
 
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