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  1. #1

    Default Ignition Timing in 95 Yukon - can't find the wire to unplug

    Everyone says the tan w/black stripe wire is behind the dash on the passenger side. Can someone point out EXACTLY where it is? I'm pulling my hair out trying to figure this out. This thing runs like a pig below 2000 RPM, and I really want to eliminate the timing as a problem (or confirm it).

    Adam Martin
    1971 Buick Centurion Formal Coupe
    1958 Buick Limited Four Door Riviera
    1995 GMC Yukon Four Door 4WD

  2. #2
    Sr. Engineer
    Join Date
    Aug 2009
    Virginia Beach, VA.


    On my '91
    The wire sits between the engine and the firewall.....and runs along the firewall.
    All inside the engine compartment.

    So I assume it is the same for your truck.

  3. #3


    From what the manual says, 96 and later are in the engine compartment at the firewall, but 95 is supposed to be behind the dash on the passenger I have pull the glove box out and there are a million wires, but no single wire to disconnect.

  4. #4
    Sr. Engineer
    Join Date
    Aug 2009
    Virginia Beach, VA.


    Are you sure??

    Check on the back side of the engine, along the firewall.....should be a black connector that needs to be unplugged.

    This is my truck::
    Click image for larger version. 

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    The wire behind the transmission filling tube is the wire you are looking for. This is a '91 Silverado.
    It is the black thing, hanging off the rusted bracket attached to the firewall.

  5. #5


    94 and 95 models have it under the dash. I've done the timing on both. It can be a PITA, but you're going to want to look up under the passenger side dash, kind of toward the rear passenger side under there. It's tan with a black stripe and has a simple connector. It'll probably be jumbled up with a bunch of others, but keep looking. It's there.

  6. #6
    Sr. Engineer
    Join Date
    Aug 2009
    Virginia Beach, VA.


    Ah, ok.
    Good to know.

    Why GM changed a good thing?? :D

  7. #7


    Mission complete. It was taped to the main harness and I couldn't see it.

    Timing is set correctly, but is still a pig below 2000 RPM. I'm going to try some 93 octane to see if it makes a difference. It feels like the timing is being retarded at the lower RPM levels, and kicks back up above ~2300 RPM.

  8. #8


    Is that still the stock motor? how many miles on it?

    If you have made any mechanical changes, you may need to tweek the timing a bit.

    After I did my rebuild, the base timing is now set 6 degrees above Zero.
    Pavement sucks... :grrrrrr:

    1994 K1500 4x4 Ext. Cab
    PCM chip and Xenon 8000k bulbs bored over .050"
    balanced Crank, 10:1 compression
    Flat top pistons,cam,ported heads
    Option Racing Cold Air Intake
    Holley Throttle Body Spacer
    Accell Igition, 45kv coil
    FloTech Headers, no CATs, dual exhuast
    Goodyear Silent Armor A/T 305/70-16
    Pioneer SupertunerIII CD USB Bluetooth
    Kicker ZX200.2 ZX Amp
    Kicker Audio COMP 10" Subwoofer

  9. #9


    I'm assuming it's still bone stock. I just bought it....118k miles.

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