91 Ignition Timing

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by 91Burb, Dec 31, 2009.

  1. 91Burb

    91Burb New Member

    Hey all,

    My 91 Suburban 1500 (with the 350) has been having issues when I put a load on the engine since I bought it a couple months ago. I put new plugs, wires, cap and rotor on it right after I got it. I found the coil was bad, replaced it and that helped some. I finally got around to checking the timing today and it was about 8 degrees advanced (supposed to be zero according to the sticker, and yes, I disconnected the timing connector). I adjusted it to zero, reconnected the connecter, disconnected the battery for about 20 minutes to reset everything, and now when I start it I get an SES light with a code 42. I was really happy when I found the timing that far off because I thought that might be at least part of my problem, but now this. Any ideas? Thanks for any input, and happy new year to everyone!!
  2. 91Burb

    91Burb New Member

    Gah, nevermind!! After I posted this I went to re-check everything and found there is another open single wire connector right next to the timing connector and I had it connected to the wrong one. Connected it to the right one and everything is good. Didn't fix the original problem of it running horrible under a load but at least it's driveable again and now I know the timing is right. I wonder though, why would the timing be that far off to begin with? Would there be some reason somebody would set it like that?
  3. Joeairforce

    Joeairforce Epic Member 5+ Years 100 Posts

    timing chain could be worn out.......

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