cranking and no start

Discussion in 'LS, LT, LTZ' started by Space Cake, Feb 3, 2020.

  1. Space Cake

    Space Cake Junior Member

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    Hi all,
    I have a 2006 cobalt ls with a 2.2 with 130k miles, used as a commuter car for back and forth to work nothing fancy or modded. I was letting it warm up out in the driveway for 10-15 mins (I live in Michigan cold here this time of year) and just before i got in it to leave I noticed it was rough idling/stumbling. Just when I got in the seat and put it in gear it died completely and would not start back up. I pushed it in the shop and charged the battery over night, it turns over good and will fire but wont completely catch and fully start.

    Things I've checked:
    - pulled code po172 (its rich a/f code to my understanding)
    -fuel pump is running for a couple seconds when the key is turned. (Fuse not blown and i tested the relay as well for good measure)
    -fuel pressure is between 45-50 psi at prime and cranking
    -pulled the coil above the spark plugs and the plugs seem to be sparking fine
    -hooked a noid light to the #3 injector (I didn't test each injector) and it was blinking when cranking
    -spark plugs don't look fouled either

    Within the last year i have replaced the coils, icm, spark plugs, plug wires, cloyes timing chain, sprockets, and tensioner (the chain had a little play in it). Regular maintenance stuff.... This thing kinda has me stumped honestly, I am leaning towards it possibly being the cam or crank position sensor maybe firing the injectors or sparks plugs out of order (if that's possible) since it fires but wont fully catch. I thought I would check here for some insight maybe someone has had a similar problem. I hate just throwing money at stuff like buying sensors etc.
     
  2. Helixal

    Helixal Junior Member

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    I had the Same symptoms on my 2006 2.2 cobalt. 163 K miles. When you turn the key engine turns over fast. I was told it was a timing chain problem.
     

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