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Hummer h3 misfire

Old Jan 28, 2025 | 09:18 AM
  #51  
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Sorry, did not know that you already moved the coil pack and cleaned the connector with CRC. Are you still using a cheap no AC Delco coolant sensor?
 
Old Jan 28, 2025 | 09:22 AM
  #52  
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It is an ac Delco coolant sensor
 

Last edited by beltz0826@gmail.com; Jan 28, 2025 at 09:31 AM.
Old Jan 28, 2025 | 09:46 AM
  #53  
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If I can upload a video here (I’m unsure) I can start the hummer and show a video of engine running. Seems to have a “slight” miss at idle but check engine light isnt flashing at idle.. only when it seems to be “under a load”
 

Last edited by beltz0826@gmail.com; Jan 28, 2025 at 09:52 AM.
Old Jan 30, 2025 | 05:14 PM
  #54  
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I’m going to check the catalytic converter’s. But could this only make one cylinder misfire? It only starts flashing when I go from park to drive (or reverse) and give it a little gas.
 
Old Jan 30, 2025 | 08:14 PM
  #55  
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Originally Posted by beltz0826@gmail.com
I’m going to check the catalytic converter’s. But could this only make one cylinder misfire? It only starts flashing when I go from park to drive (or reverse) and give it a little gas.
Did you check fuel pressure?
 
Old Jan 30, 2025 | 08:31 PM
  #56  
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Originally Posted by hummerz
Did you check fuel pressure?
I put a new one in around 3 years or so ago. What should that read? I will check that next
 

Last edited by beltz0826@gmail.com; Jan 30, 2025 at 08:57 PM.
Old Jan 30, 2025 | 09:58 PM
  #57  
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57psi


 
Old Jan 31, 2025 | 08:01 AM
  #58  
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I checked the front weld ring and rear weld ring with a IR temp gun. The front read 325 (max was 352) and the rear is at 511.. could this be the issue?
 
Old Jan 31, 2025 | 08:38 AM
  #59  
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A properly functioning catalytic converter will typically have a rear weld ring temperature that is around 150 degrees Fahrenheit higher than the front.
 
Old Jan 31, 2025 | 11:23 AM
  #60  
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I switched coil 5 and 4 around again (boredom) and still a misfire on cylinder 5 and also got code p0106.. was looking to replace the map sensor but there isn’t a ac delco one?? Any suggestions?
 

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