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HEI relay install(PIC'S)

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by BobK, May 26, 2004.

  1. BobK

    BobK 1/2 ton status

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    Petrolia,Ontario,Canada but working in Port Huron,
    HEI relay install(PIC\'S)

    I installed a relay to power up my HEI today.
    Pretty easy install.
    I also installed a relay for my heated o2 sensor.
    Here are a couple pic's.
    ALL the pic's can be viewed HERE

    The relays I used.rated at 40 amps.They are DPDT(Double Pole Double Throw) relays.$3.00 each at my local electronics wharehouse.
    [​IMG]

    Ran these wire from a existing IGN. splice at the IGN. switch to trigger the relays on.
    [​IMG]

    Here is the splice I had made at the IGN. switch(kinda hard to see)
    [​IMG]

    I replace my existing 1 wire o3 sensor with a 3 wire(heated) o2 sensor.Here is the retrofit harness.
    [​IMG]

    Here's the new 3 wire o2 sensor installed in the drivers exhaust manifold.
    [​IMG]

    This is the power feed to the relays.Red goes to the HEI relay(12g wire).Blue goes to the o2 sensor relay(16g wire).
    The circuit is protected by a 12g fusable link(light blue wire).
    [​IMG]

    All hooked up now.
    [​IMG]

    Here's the voltage now being sent to my HEI coil 14.12volts.
    Should produce a nice arc!
    [​IMG]

    Took me an afternoon to do this project (pissed around alot though) and maybe $10.00 in materials.
     
  2. Yukon Jack

    Yukon Jack 1/2 ton status

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    Re: HEI relay install(PIC\'S)

    I'm electrically challanged so bear with me - does the relay help in getting the better voltage reading. I've always just seen the HEI wired direct - this is a better way I take it?
     
  3. BobK

    BobK 1/2 ton status

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    Re: HEI relay install(PIC\'S)

    The more voltage you can supply the HEI the better it performs.
    Better/hotter spark...stuff like that. /forums/images/graemlins/grin.gif
     
  4. Burt4x4

    Burt4x4 3/4 ton status

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    Re: HEI relay install(PIC\'S)

    Looks like you did a nice and clean job!! /forums/images/graemlins/waytogo.gif /forums/images/graemlins/woot.gif
     

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