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Electronic Spark Module (Need Help)

Discussion in 'The Garage' started by Justin Fleming, Sep 17, 2006.

  1. Justin Fleming

    Justin Fleming 1/2 ton status Premium Member

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    Hello

    I have an 86 k5 blazer and I beleive the electronic spark module is bad. I have put in a complete new tune-up, entire new distributer and the only thing left is this module. Does anyone have any experiecne with these modules and how to trouble shoot the module or wiring. Such as what wire should have power to it and what not. The last time the truck would not start I tapped on the module and then the truck started right up.

    thanks
     
  2. 1979jimmy350

    1979jimmy350 1/2 ton status

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    are you taking about the one on the fire wall? if so it has nothing to do with the truck starting all it is for is the knock sensor.
     
  3. mudbog42

    mudbog42 1/2 ton status

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    Yup sounds like your module, soon the truck won't turn over at all. I had to replace mine a while back, I also have an 86. Is it a 4 pin or a 7 pin module. Either way they shouldn't be that much, the 4 pin is cheaper though but I had a 7 pin, anyways it should work fine when you replace it
     
  4. btolenti

    btolenti 1/2 ton status

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    I think he is talking about this module.

    According to my information, here is the pinout.

    Brown wire - AIR select valve control
    Pink/Black wire - Power input
    Black/Pink wire - Air Diverter Valve Control
    Light Blue Wire - Carb fuel control - mixture solenoid
    Gray wire - EGR solenoid

    esc203.jpg
     
  5. opfor2

    opfor2 1/2 ton status

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    I think he's talking about the electronic ignition control module located inside the distributor. It's an easy fix, but do your self a favor and get a real OEM AC Delco module. Take it from someone who's had numerous aftermarket one's go out on him..
     
  6. 73k5blazer

    73k5blazer Unplug the matrix cable from the back of your head Premium Member

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    I've a '86 V6 with the ESC. It sounds like the module (in the distrubtor). The price for these modules is ridiculous though. The stanadard HEI 4pin used from 73-85 is $20 at most places. The 5pin one for my ESC V6 was $120. The california 7-pin one was even more. I just bought an accell drop in replacment distributor without the ESC for $180 and called it done. (I was rebuilding the whole engine anyway..)
     
  7. Justin Fleming

    Justin Fleming 1/2 ton status Premium Member

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    Well like I mentioned above the distrib. is brand new...which includes a new module in the distrib.

    The only thing that I thought was left was the electronic ignition control module that is located on the fire wall behind the glove box. I have read that some say that the module has nothing to do with the truck starting? This seems odd as I can unplug it while the truck is running and it shuts right down? I could not access the bitmap attached to the one reply. Can anyone lend any more advice?

    thanks
     
  8. btolenti

    btolenti 1/2 ton status

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    Ah, it sounds like you have a fully computer controlled carb and everything....just like my K5 used to have. Their is an ECM behind the glove box, similar in shape/size to the TBI computers.... I still have my old one, if you need it...

    IMG_0586.jpg
     
  9. Justin Fleming

    Justin Fleming 1/2 ton status Premium Member

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    can you email me that picture at jfleming01@charter.net so I can see if we are talking about the same thing?

    thanks
     
  10. dyeager535

    dyeager535 1 ton status Premium Member

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    The setup needs to be clarified. It could be ESC or it could be CCC. But the emissions tag on the truck would tell, CCC was CA only for trucks. (as your experience attests to. :))
     
  11. 73k5blazer

    73k5blazer Unplug the matrix cable from the back of your head Premium Member

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    Yeah, there's definitly differences, My '86 c10 V6 is ESC only, carb was not computer controlled, just a regular q-jet.

    If it's ESC only you should have a 4-pin weatherpak conenctor coming out the back of the distributor, disconnectit and you can bypass the ESC computer by jumping pins A & C on the distributor side. Truck should run. If not, you have a distribuor problem. Ignition coil, pickup coil or module. There's some tests for all of them , if you bought a rebuilt distributor, alot of times they don't replace the module, if it tests good, they put it back. Because they are so expensive for the ESC trucks.
     
  12. Justin Fleming

    Justin Fleming 1/2 ton status Premium Member

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    Ok guys Brandon was nice enough to send me the two photos that he had listed. The module that I am talking about is not either one of those pictures. The module looks just like the ECM but in a little smaller scale and only one plug in connection. Auto Zone called it a Electronic Spark Control Module. I have not been able to jump the terminals at the dist. and see if the truck runs as I am dealing with some unexpected family stuff.

    A big question that I have is: What kind of siginals does the ignition switch send to the truck? Is it only a power signal or does it also send other signals that would be controlling spark? Should I try replacing the ignition switch before the 120 dollar ignition controller?

    thanks
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    As far as I've been able to discern, different years did different things. Early on, the ESC was tied into the dist. via the knock sensor...only when knock was detected was timing retarded. Later on, the distributor was controlled solely by that module.

    The way to tell is if there is vacuum advance. If no vac advance cannister, its all controlled via the module. If vac advance, it's knock retard only. I suspect based on others experiences that even the early ones can fail and cause problems like you describe.
     
  14. Justin Fleming

    Justin Fleming 1/2 ton status Premium Member

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    Ok guys I am really at lost now. I have replaced the electronic spark controller and the truck still will not run. I have also tried jumping the A @ C pin as mentioned above, still no luck. Where should I be looking next? This thing is killing me right now.....

    thanks
     
  15. dyeager535

    dyeager535 1 ton status Premium Member

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    What exactly is not happening, other than it not starting, to make you think it was the ESC system in the first place?
     
  16. Justin Fleming

    Justin Fleming 1/2 ton status Premium Member

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    The truck has no spark.....call me I would apprecate it

    2487896958

    thanks
     
  17. dyeager535

    dyeager535 1 ton status Premium Member

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    I would if I were near a phone. Although I think the quite-a-ways--international call would tend to get pricey. :)

    No spark. You getting 12V into the distributor when key is in run AND when it's cranking?
     
  18. Justin Fleming

    Justin Fleming 1/2 ton status Premium Member

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    yes I get the 12v when cranking and key in on position.

    How can I manually fire the coil to see that it is working correctly?
     
  19. Justin Fleming

    Justin Fleming 1/2 ton status Premium Member

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    Does anyone else have any ideas?

    thanks
     
  20. 73k5blazer

    73k5blazer Unplug the matrix cable from the back of your head Premium Member

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    Ok, back to basics. Three things required for engine to run, Air, Fuel, Spark.
    Air, usally isn't a problem. That leaves fuel and spark. You sure there's gas to the carb? (After trying many time to crank, you should be able to smell it quite easily anywhere near the carb).
    Check for spark,basic poor mans test is to remove a spark plug, put it in it's boot, ground it to the frame and have a helper crank the motor. This is HEI, it should make you almost drop the thing,the HEI spark should be that strong. If no spark,or a weak spark (weak defined in this case as you can hold the boot in your hand with the plug end grounded with the engine cranking), then you have a distributor problem.
    There are tests for the ignition coil and the pickup coil.
    http://www.autozone.com/servlet/UiB..._us/0900823d/80/11/43/ad/0900823d801143ad.jsp
    You need an ohm meter to perform the tests, very basic.
    Module can be tested at most autoparts stores.
    I'm pretty close to you, if you can't get something out of the tests, I may be able to help you out, but not until Monday sometime, mabey Sunday night.
    If I were to guess, at this point, I'd guess ignition coil. They are cheap at the store, like $20 for a normal one, $50 for a good one. Might be worth the $20 just for a trial and error. Check for spark first though....
    Does it even hint at wanting to start? Does is cough or anything?
     

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