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2012 gmc issue

Discussion in 'Gearheads' started by Preacherman, Jan 29, 2021.

  1. Preacherman

    Preacherman Sharpshooter

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    It is a 2012 gmc Sierra 1500 sle w/5.3l gas engine. I tried to prime it but it did not work.

    The maf was replaced w/aa new maf.
     
  2. Preacherman

    Preacherman Sharpshooter

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    Yes, it runs and idles as it should after a few seconds at cold start. Once the engine is warm the issue is gone.

    It did have two codes for bank 1 &2 of being too rich. Those were cleared up once maf was replaced.
     
  3. OkdRooster

    OkdRooster Marksman

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  4. Preacherman

    Preacherman Sharpshooter

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    Yes, fresh oil change, thermostat and coolant.
     
  5. Glock 40

    Glock 40 Problem Solver

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  6. 918evo

    918evo Sharpshooter

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    Coolant temp sensor, injectors bleeding while engine off, or blown HG(s) is where I would start. First check coolant temp sensor data and if that's ok. Might pull a plug after no-start condition and see if it's wet with fuel or use a borescope to look for coolant. I would run the injectors dry by removing the fuel pump fuse and let it sit overnight. Put the fuse back in and see if it fires up when cold. If there is a schrader valve, you could just release the fuel pressure.
     
  7. Preacherman

    Preacherman Sharpshooter

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    Good start. It was the coolant temp sensor. However the fuel pressure was only 55psi but I did not use thread tape so maybe its actually a little higher.
     

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