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Thread: TPS vs MAP AE 7427 $0E

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  1. #1
    Fuel Injected! CDeeZ's Avatar
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    TPS vs MAP AE 7427 $0E

    I'm still working on getting the AE acceleration enrichment to play nicely on my TBI. I'm still getting a lean pop when the throttle is planted open quickly.

    I have copied over every AE parameter from BMHK 454 bin into my bin. I did this because I figure these AE parameters ought to be a closer start for me since I also have a large throttle body and even more plenum volume from the single plane intake. Additionally, This bin was setup for the higher pressure 454 TBI, which also ought to be closer for me since I'm running about 28 PSI..

    I have been increasing the Delta TPS and Delta MAP AE tables by 20% or 30% at a time, and also reducing the filter tables ($4B3A and $4B62) values by 10%... RBob mentioned this.
    These changes have helped with the lean pop, some, but the issue is still there. Also, this has made the engine bog down way rich (10 AFR on WB02) when just tipping into the throttle from a start.

    I'm thinking that I need LESS TPS AE at this point as indicated potentially from the rich bog on tip in. AND, that I need MORE MAP AE to cure the lean pop..... Sometimes It will even lean pop when climbing a hill at interstate speeds as the load and MAP increase....

    Thoughts?

  2. #2
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    In the beginning of my tune learning I chased what I thought was a lean pop. After install WB realized it was not lean pop but anticipated spark retard. I lowered the amount of spark retard allowed and increased advance in the 60-85 map area and haven't had a pop in years. I had a friend with mod 454 that had similar results. Your mileage might be different.
    6395, BHDF, 7.4 BBC lightly modded now 6395 BMHM back to BHDF

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    I've run into the same problem. Popping is not rich, it's lean. IIRC there is a max PW size that needs to be increased. Then you'll probably end up reducing values in the other two tables.

    You'd think the high pressure cal would be closer but the high pressure 454 had a TBI specific manifold which had a smaller volume than the old carby manifold plus adapter.

    Increasing spark advance or changing the spark retard limit can increase how quickly the engine accelerates which in turn draws the fuel/air mix out of the manifold before it can ignite.

    Edit: Yes, the maximum Async pulsewidth value will limit total AE.

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    Quote Originally Posted by 1project2many View Post
    I've run into the same problem. Popping is not rich, it's lean. IIRC there is a max PW size that needs to be increased. Then you'll probably end up reducing values in the other two tables.

    You'd think the high pressure cal would be closer but the high pressure 454 had a TBI specific manifold which had a smaller volume than the old carby manifold plus adapter.

    Increasing spark advance or changing the spark retard limit can increase how quickly the engine accelerates which in turn draws the fuel/air mix out of the manifold before it can ignite.

    Edit: Yes, the maximum Async pulsewidth value will limit total AE.
    Lack of timing advance can also cause popping.

  5. #5
    Fuel Injected! CDeeZ's Avatar
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    Quote Originally Posted by myburb View Post
    In the beginning of my tune learning I chased what I thought was a lean pop. After install WB realized it was not lean pop but anticipated spark retard. I lowered the amount of spark retard allowed and increased advance in the 60-85 map area and haven't had a pop in years. I had a friend with mod 454 that had similar results. Your mileage might be different.
    Interesting. I know this is a lean pop because I can see it on the WB02 gauge itself, as well as the logs. I have wondered if I don't have enough timing now though.

    Quote Originally Posted by 1project2many View Post
    I've run into the same problem. Popping is not rich, it's lean. IIRC there is a max PW size that needs to be increased. Then you'll probably end up reducing values in the other two tables.

    You'd think the high pressure cal would be closer but the high pressure 454 had a TBI specific manifold which had a smaller volume than the old carby manifold plus adapter.

    Increasing spark advance or changing the spark retard limit can increase how quickly the engine accelerates which in turn draws the fuel/air mix out of the manifold before it can ignite.

    Edit: Yes, the maximum Async pulsewidth value will limit total AE.
    Well what I was saying is that increasing the Delta TPS and MAP AE seems to help lessen the lean pop when you smash the throttle open quickly, however, those same changes appear to have made it overly rich on very light throttle tip in pulling away from a stop. It literally pegs my WB on 10 AFR for a second or two. I've read several threads on TGO where Dewey talked about having a similar/same issue... Here's one I stumbled on
    https://www.thirdgen.org/forums/tbi/...ifold-big.html

    Where is this max PW you speak of? Do you think the 350 AE parameters would be closer??? I thought with the big throttle body and single plane carb intake it would be closer, but now that you mention the 454 manifold was smaller.......

    Quote Originally Posted by Fast355 View Post
    Lack of timing advance can also cause popping.
    I was running the stock L05 timing table from the $0E bin I started with. I then copied over the timing table from Brian, (sturgillbd on here). His timing table IIRC has a little more advance in it. It seemed to help mine with the lean pop when you smash the throttle open....

    I'm running TrickFlow aluminum heads https://www.summitracing.com/parts/SUM-162108

    Maybe with these new heads and the single plane, flat top pistons and everything else I don't have near enough timing advance for this combo? Anyone have a timing table for such a combo that might be closer in the ball park vs what I've tried?

    Initial spark advance is 3*
    Last edited by CDeeZ; 3 Weeks Ago at 12:22 PM.

  6. #6
    Fuel Injected! PlayingWithTBI's Avatar
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    I have the same heads and a 46mm TB with 18LB spring on a 3704 intake (bored out to 48mm).

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