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computer keeps advancing timing...why?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 90K5, Apr 20, 2003.

  1. 90K5

    90K5 1/2 ton status

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    if i time my engine to 0 degrees, or a few degrees advanced, with the tan wire unplugged, then disconnect the battery and plug the wire back in, it starts and runs at 20-25 degrees advanced...why?
     
  2. K5Jimmy

    K5Jimmy 1/2 ton status

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    I just checked the timing on mine, and it's on 0* with the wire disconnected...didn't think to look at it after I reconnected the wire, but I'll be happy to do that tomorrow just to see what it does...I flunked emissions...low speed HC(ppm)....Standard 159, my reading 355....at high speed standard is 155, mine is 151....All the other numbers are quite well within range...I changed the EGR and will retest after I ask a question or two in a different post about timing...
     
  3. 90K5

    90K5 1/2 ton status

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    i'd appeciate it if you could do that...maybe your 02 sensor is bad, or the cat...sad thing is, im just getting this thing running right again, and and right back to where i was before i tried to get it inspected.
     
  4. K5Jimmy

    K5Jimmy 1/2 ton status

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    New O2, exhaust is 4yo, headers, new cats, Magnaflows...hopin' it's just the EGR...
     
  5. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    What you just desrcibed is normal, timing is done with the tan wire disconnected and set timing to zero then turn engine off and reconnect the tan wire and the timing should read somewhere around 20-25 degrees. The computer will adjust as nessasary.
     
  6. 90K5

    90K5 1/2 ton status

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    yeah, ive been driving it like that, and its fine...guess this was kinda useless...just dont understand why it wasnt advancing it when i had it set to 0 and the tan wire plugged in...guess i wont worry about it. thanks everyone
     

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