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Thread: Hypothetical ignition question

  1. #1
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    Hypothetical ignition question

    This post isn't is it a sensible idea but rather would it work. 7427 would be the pcm for this discussion. If you had a second unit with map/power/grounds all connected and all the spark settings at zero and you connected the ignition output of the original pcm into the signal port of the second pcm and the ignition output then to the hei 8 module. Would it work? The one problem might be instead of the pcm planning the next ignition event it might end up two events. You can probably tell it is chilly out today and I am not in the shop.
    6395, BHDF, 7.4 BBC lightly modded now 6395 BMHM back to BHDF

  2. #2
    Super Moderator Six_Shooter's Avatar
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    I'm not sure what you're trying to do here, so you may want to explain it it a bit more in detail and/or use visuals?
    The man who says something is impossible, is usually interrupted by the man doing it.

  3. #3
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    Let's say we have two pcm's, 1 primary, 2 secondary. From hei 8 to primary A4, from primary F11 to secondary A4, from secondary F11 to hei 8 est. if it were anything more than hypothetical it would be the secondary unit used for something the primary couldn't do.
    6395, BHDF, 7.4 BBC lightly modded now 6395 BMHM back to BHDF

  4. #4
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    Years ago one of the SYTY guys used a 7749 to control the engine and a 7427 to control a 4L60E. As I remember (I could be wrong) he used the same sensors for both boxes, including the ignition module. The ecm connected to the 5V bypass and the EST lines at the module would control timing. I think that there's no need to go from ECM output to 2nd ECM input then from 2nd ecm output to EST. I'd avoid the complication of having two ecm's involved in timing calculations.

  5. #5
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    I agree that having two units doing timing calculations might be troublesome. Wandering mind was also wondering about a 2-3 bar map sensor in the second
    Last edited by myburb; 11-23-2015 at 09:25 AM.
    6395, BHDF, 7.4 BBC lightly modded now 6395 BMHM back to BHDF

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