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Wiring mystery

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  #11  
Old 05-19-2018, 03:59 PM
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So you have no spark, no switching signal from the pcm to the icm and good power and grounds to the icm and coul?

George
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  #12  
Old 05-19-2018, 04:09 PM
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I did all the tests on line and YouTube for ground and power and signal. I checked the pink wire from the ignition switch to make sure I have power with the key turned. I even put in a new coil and ignition module but no spark still. All that is left is the see if I get the intermittent 6 volts as the crank pulley is turned.
 
  #13  
Old 05-19-2018, 05:28 PM
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Then yes crank sensor is next.

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Old 05-19-2018, 05:37 PM
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Originally Posted by surreybrad
I did all the tests on line and YouTube for ground and power and signal. I checked the pink wire from the ignition switch to make sure I have power with the key turned. I even put in a new coil and ignition module but no spark still. All that is left is the see if I get the intermittent 6 volts as the crank pulley is turned.
I'm still not clear, is your engine cranking or do you have a no crank situation?
 
  #15  
Old 05-19-2018, 06:02 PM
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I'm sorry, i thought it was obvious that it was cranking over because it was a "no spark" issue. If an engine wouldn't crank I would be looking at the ignition and starter/battery area. I believe I mentioned that everything else electrical was fine and I established their was fuel and no reason to check fuel pressure. No, the only issue is NO SPARK. Once that matter is resolved, and hopefully with the final test at the crank sensor identifying the problem, I can get on to resolving the problem.
 
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Old 05-19-2018, 06:58 PM
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Originally Posted by surreybrad
I'm sorry, i thought it was obvious that it was cranking over because it was a "no spark" issue. If an engine wouldn't crank I would be looking at the ignition and starter/battery area. I believe I mentioned that everything else electrical was fine and I established their was fuel and no reason to check fuel pressure. No, the only issue is NO SPARK. Once that matter is resolved, and hopefully with the final test at the crank sensor identifying the problem, I can get on to resolving the problem.
Ok, thanks...I wan't dead positive and didn't want to make assumption. While you're waiting for your help, a quick check you can do is crank your engine while watching your RPM gauge. It should bounce (flutter) slightly off of 0 as you crank. If not, and it stays rock solid, that can indicate CKP sensor or circuit problem.
 
  #17  
Old 05-19-2018, 07:03 PM
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Thank you for that tip. i will check that right away as I wait for my friend to make it here to get going on that test. love the ZR2 but those skid plates can be a real pain sometimes. Let you know the results.
 
  #18  
Old 05-19-2018, 07:24 PM
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Originally Posted by rockp2
Ok, thanks...I wan't dead positive and didn't want to make assumption. While you're waiting for your help, a quick check you can do is crank your engine while watching your RPM gauge. It should bounce (flutter) slightly off of 0 as you crank. If not, and it stays rock solid, that can indicate CKP sensor or circuit problem.
The tach moved off the fin to the zero and fluttered while cranking. Does that mean the crank sensor is working? I sure would like to not have to do that test. If it's not the crank, whatsw left? The PCM?
 
  #19  
Old 05-19-2018, 07:47 PM
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Can I take a PCM from another Blazer? I have one from a 99 that I know worked until the engine blew. Can I just swap it out?
 
  #20  
Old 05-19-2018, 08:07 PM
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Here is a new discovery. I just took off my negative battery cable and it's sparking like crazy when the terminal is touching the post. I've always taken the negative off first to prevent sparking that can occur if you remove the post first. IveI never heard of neg sparking. Should I be pursuing this?
 


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