ESC bypass

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by TheEmissary, Jan 29, 2001.

  1. TheEmissary

    TheEmissary Registered Member

    Apr 15, 2000
    Likes Received:
    Houston, Texas
    Since last May, I have experienced frequent surging, and I have browsed another 73-87 Chevrolet/GMC URL:

    Tried everything to no avail, until a posting from another third party revealed how to bypass the ESC (illegal in California or in a jurisdiction where I/M inspection {emission testing}).

    On the ESC pigtail, there are 4 wires, labeled A, B, C, and D. Here's the colors:

    A: black
    B: white
    C: green
    D: brown

    To make the ESC distributor operation, without switching to a non-ESC, find the black and green wires (terminals A and C), and connect them together. What I done was find another plug-in harness from a derelict 83 Blazer in a local bone yard, and clipped the A and C terminals per the directions. The other wires aren't used (either tape them or have them clipped).

    After firing up the Vigilante this morning, there was a lot of excessive spark knock (probably from heavy carbon deposits), and after a cruise at 65 mph for 15 minutes, the spark knock went away. I set my distributor at 6 degrees BTDC, and noticed that the surging was gone.

    Note: the bypassing method is well-known to former Chevrolet/GMC mechanics that have serviced ESC-powered pickups when owners experienced chronic surging. Here's the URL for more:

    The Emissary
    1981 K5 Blazer 4 x 4
    305 (LE9)/THM350C/NP208

    Other vehicles:
    1975 Nova

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