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Thread: ECM Test Bench

  1. #46
    Super Moderator Six_Shooter's Avatar
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    I haven't had a problem getting a good tach signal from mine, with several different ECMs. The EST error is there, but I can simply get rid of that by adding a resistor that wire, just haven't got around to that yet.
    The man who says something is impossible, is usually interrupted by the man doing it.

  2. #47
    RIP EagleMark's Avatar
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    But no spark advance in data without EST/ICM ref hi and low.

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  3. #48
    I did add a resistor so I would not get a knock error and A 1k or the orange led in the picture my mil .

  4. #49
    Super Moderator Six_Shooter's Avatar
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    Quote Originally Posted by EagleMark View Post
    But no spark advance in data without EST/ICM ref hi and low.
    What?

    I get SA data in my logs using the JimStim. FWIW, I do use both ref hi and lo.
    The man who says something is impossible, is usually interrupted by the man doing it.

  5. #50
    RIP EagleMark's Avatar
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    I really don't remember why? Not sure how spark would be accurate without? Plus a error 42, glad I sold it, now I don't have to figure out why...

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  6. #51
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    FWIW, I do use both ref hi and lo.
    That's the correct way. REF Lo is not a "ground" wire. It's an independent return path for the REF Hi signal.

  7. #52
    Fuel Injected! geewhiz's Avatar
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    My donor TBIs came from a 1987 7.4L C20, w/auto, and another from a 1987 7.4L K30, w/auto.

    Will this work for me?
    Noid Light OTC7188 GM model 700 series TBI

    http://www.ebay.com/itm/NEW-Noid-Lig...-/151197731961

    I would like to start cleaning up the wiring harness, and messing around with the compounds, testing the pieces and checking to see if they all function.

    This looks more like the one, and half the price!
    http://www.summitracing.com/parts/oes-25140/overview/
    Last edited by geewhiz; 03-08-2014 at 07:53 AM. Reason: update
    John

  8. #53
    RIP EagleMark's Avatar
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    Yup, they would be fine. I got a full set with several differant noids for like $40.

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  9. #54
    Fuel Injected!
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    http://www.amazon.com/SainSmart-Port..._7fUdxbYPQX1KW


    so I picked up one of these for a project and it has a built-in wave form generator as well. it can output sign, square, saw. and selectable freq. my only wonder is how much current the ecm would need. it's a tiny little thing and I guess it wouldn't put out but a few ma.


    wonder if it's worth trying to setup a test bench.

  10. #55
    billygraves
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    Just an Old way I use to test the ECM with a Ref Pulse signal without the engine running.

    When I repaired buy-back vehicles I hated to drive them and walk back. "May Walk" meaning if you drive it you may walk.

    Anyway, with situations where a stall or run/stall then no-start, I used a weller 200?? watt soldering gun. I unplugged the Injectors and installed a noid lite. (It will full up a TBI Throt bore in a matter of seconds.) Unplug the coil wire on a V engine and install a Spark Plug tester ST-125. Turn the key on, hold the soldering gun near the Dist Pick up or near the crank trigger. (Watch not to melt anything) Used a Tech-1 to record RPM ect. With the time/heat sensitive problems, it took a bit but worked. With wiring and connectors that would open or short I mearly moved each section of the suspected harness/connector until the spark quit. (Some had more failures than just one)

    When setting up a TCM quick test bench at home, I used a say 89 V-8 12 volt powered up dist module screwed to a alum plate, and grounded. A pick-up coil plugged into the module. I taped another pick-up coil directly to the other. On top of it. The spare pick up I soldered, and shrink tubed a 110 volt cord and plugged it into the 110 volt wall socket. If you do the math you'll see the spds. 4 pulses per rev at 60 hz a sec. Depends also on if a 8 6 or 4 cyl. I used the test for the ISS and OSS. ISS has 31 pulses per rev and the OSS has 40 pulses per rev. Verified with Tech-1.

    Maybe instead of the drill to spin the distributor for your test bench, you might use the double pickup coil. It does work. (I have not tried this on the 60 deg V-6 BUT the same 6 pulse wheel with one syn was on the early 2.5L TBI engines with DIS and it worked very well. The module will get hot, so a thick heat sink)

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