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Thread: 86 GMC 5.3 4L60E Problems..

  1. #1
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    86 GMC 5.3 4L60E Problems..

    Looking for some Help please!

    Recently did the LS swap on my 86 Gmc Swb. 5.3/ 4L60E out of a 2000 gmc. Only mods are Long tubes/ Air intake. Been learning how to tune. I've done a couple things to make it wayy better than the stock tune but still got some issues and getting a little frustrated. I'm hoping yall can take a look at my tune and scan and give me some pointers.

    Issues I'm having:

    - Won't shift at WOT. (Pretty sure this is not my shift scheduling/rpm because I did have it shifting good at WOT, but started messing with VE, PE, other stuff and now having the issue). Dosen't bang rev limiter, just loses power and dosent shift

    - o2 sensor voltages are super low when WOT ( I feel like this might be the reason it wont shift at WOT because its so lean)

    - Ltft's still very positive. I've done the procedure of disabling maf, logging Ltft's, copying LTFT% into VE table, smoothing, a couple times. Seemed to help a little.

    I feel like it needs more fuel put don't know where to put it in.

    PE EQ Ratio is 1.174. (14.68/12.5)

    I know I should be tuning with a wideband but money is tight at the moment.

    Thanks in advance.
    Attached Files Attached Files

  2. #2
    Tuning Addict 5FDP's Avatar
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    May 2012
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    What's your fuel pressure like?

    I see if far too often in swaps where the fuel pressure is too low.

    You're also not suppose to disable the computers knock settings if you are running knock sensors. You'd never know if you really had knock/ping if you won't let the computer show you.


    If it was working before, then go back to a calibration where it was and start over with minimal changes at a time. Then see if something you are doing is causing the issue.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
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    Quote Originally Posted by 5FDP View Post
    What's your fuel pressure like?

    I see if far too often in swaps where the fuel pressure is too low.

    You're also not suppose to disable the computers knock settings if you are running knock sensors. You'd never know if you really had knock/ping if you won't let the computer show you.


    If it was working before, then go back to a calibration where it was and start over with minimal changes at a time. Then see if something you are doing is causing the issue.
    Thanks for the reply and looking at the file.

    I've never actually tested the fuel pressure. Pump has been working. Still something I should check tho.

    You're totally right about the knock settings. I thought I has those filled in. I was messing with it zeroing it all out, but I'd rather have it functional like you said.

    Yeah I should probably back track a little. That's a place to start.

    Needed another opinion. Thanks