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

High EGTs at idle

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  #31  
Old 05-20-2009, 11:18 AM
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did you just hook up that pyro
 
  #32  
Old 05-20-2009, 01:24 PM
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Originally Posted by 2500HeavyDuty
did you just hook up that pyro
No, I put it in a few years ago, sent it off to autometer, and reinstalled it about 6 months ago or so.

So, checked the valve lash today. Couple of the exhaust valves were a little loose, so I tightened them up. Started up the truck, pyro jumped to about 200 and then went up slowly to a little over 300. Drove it around, all my operating EGTs seemed about 100 degrees or so lower. Parked the truck. Let it idle for about 10 min...won't come down below 450. Took the air filter off, no change.
 
  #33  
Old 05-20-2009, 08:52 PM
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Did you send the gauge and the thermocouple probe or just the gauge?
 
  #34  
Old 05-20-2009, 08:55 PM
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Originally Posted by daveO
No, I put it in a few years ago, sent it off to autometer, and reinstalled it about 6 months ago or so.

So, checked the valve lash today. Couple of the exhaust valves were a little loose, so I tightened them up. Started up the truck, pyro jumped to about 200 and then went up slowly to a little over 300. Drove it around, all my operating EGTs seemed about 100 degrees or so lower. Parked the truck. Let it idle for about 10 min...won't come down below 450. Took the air filter off, no change.

I would check the lash again if its off I would pull the push rods and make sure there not bent then I think your gonna have to check the cam/lifters.
 
  #35  
Old 05-20-2009, 09:23 PM
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Originally Posted by relay93
Did you send the gauge and the thermocouple probe or just the gauge?
I sent just the gauge in, but when they sent it back, they included a brand new probe as well.

I was thinking it could be a bent pushrod. I take it to check them, I'm gonna have to take the rocker pedestals off? Also, while checking the lash, I noticed that the rockers kinda slid back and forth on the pedestal shaft (I think that's what it's called). Is this normal?
 
  #36  
Old 05-20-2009, 09:43 PM
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I thought the lifters were solid? I guess I don't understand the bent push rod other than not enough lift of the rocker to operate valve properly.
Originally Posted by 94 12valve
I would check the lash again if its off I would pull the push rods and make sure there not bent then I think your gonna have to check the cam/lifters.
 
  #37  
Old 05-21-2009, 06:20 PM
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Originally Posted by daveO
I sent just the gauge in, but when they sent it back, they included a brand new probe as well.

I was thinking it could be a bent pushrod. I take it to check them, I'm gonna have to take the rocker pedestals off? Also, while checking the lash, I noticed that the rockers kinda slid back and forth on the pedestal shaft (I think that's what it's called). Is this normal?
yes you have to take the pedestals off to get the pushrods out. with the head bolts and that other little bolt the pedestal should not move and the rocker arms should move a little side to side but not foward and back.

---AutoMerged DoublePost---

the lifters are solid but if there wore your not gonna get as much lift as you should.

Originally Posted by relay93
I guess I don't understand the bent push rod other than not enough lift of the rocker to operate valve properly.
thats right, if you don't have the right amount of lift your not getting air therefore running hot
 

Last edited by 94 12valve; 05-21-2009 at 06:20 PM. Reason: Automerged Doublepost
  #38  
Old 05-21-2009, 06:35 PM
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Dave where is the EGT probe installed? Could the probe be installed to deep and resting on the exhaust manifold? Do you know anyone with thermal scanner to see if you have one cylinder that is hotter than the other?
Just some more thoughts and easier to check.

Good Luck.
Originally Posted by 94 12valve
yes you have to take the pedestals off to get the pushrods out. with the head bolts and that other little bolt the pedestal should not move and the rocker arms should move a little side to side but not foward and back.

---AutoMerged DoublePost---

the lifters are solid but if there wore your not gonna get as much lift as you should.



thats right, if you don't have the right amount of lift your not getting air therefore running hot

I would think if it was not getting enough air on the intake side would cause that cylinder to be rich. Would one bent rod cause that much heat?
 

Last edited by relay93; 05-21-2009 at 06:40 PM.
  #39  
Old 05-21-2009, 06:40 PM
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So, the rocker arms have play back and forth like, towards the front and back of the truck, but they don't move from one side to the other. What type of lift should I be getting at the rocker arm on the pushrod side? Like if I put a dial indicator on it to verify lift? Also, since the lifters are solid, I take it the only way they would go bad is if they are just worn down. Is this the same for the cam lobes as well?? Thanks for all your input so far guys! I appreciate it.
 
  #40  
Old 05-21-2009, 06:41 PM
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I have no idea where his is installed but mine is right before the turbo twords the rear 3 cylenders ( because they run hotter then the front 3). I used a heat gun and shot my manifold to make sure there about the same.

The reason I think its a pushrod/cam issue is because he set the valves and made everything better, ran it and I slowly got worse thats why I think when he rechecks the lash its off again.
 


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