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Thread: 7.4L 7427 $31 - PE and 4L80E shifting help please

  1. #1
    Carb and Points!
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    7.4L 7427 $31 - PE and 4L80E shifting help please

    Hi all - I'm helping a friend with 7.4L do some tuning in TunerPro. Coming from HPTuners, with more modern ECM's I'm a little stumped on a few things. Any help would be greatly appreciated!

    PE - Something seems goofy with the PE enablement. The log file says it's going into PE, but IPW isn't reacting like I think it should. It seems to stay lean for a few seconds before richening up like it should. I don't think it's the VE table because a similar cell (RPM & MAP) in the next gear is rich like it is supposed to be. See the marked spots showing about 3500rpm in each gear. It gets richer, closer to 12.0 AFR I expected, with each gear. Any ideas?

    V5 PE.jpg

    Desired AFR - Whether CL or OL, Desired AFR seems to always wander around 12AFR. It goes into CL no problem and oscillates around 14.7AFR so I'm not sure what's going on here. Anybody know why Desired AFR is just wandering around? Is there a different desired AFR to log that actually tells what the ECM is commanding?

    4L80E Shifting - Any pointers on firming up shifts? The only shift time settings I see in the BIN is Desired Shift Time Altitude Gain vs. TPS vs. Shift. What is this? This looks like something I should be looking for but looks more like a special case than base shift time settings.
    Attached Files Attached Files
    Last edited by dingo16123; 08-03-2018 at 03:09 PM.

  2. #2
    Fuel Injected! dktool's Avatar
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    Post the xdf file you're using.
    Dean

  3. #3
    Super Moderator dave w's Avatar
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    Check the PE delay parameter. Some $31 .bin file will have up to 60 seconds of PE delay.

    dave w

  4. #4
    Carb and Points!
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    XDF added to the original post. This file came from the TunerPro definition download page.

    PE delay should already be 0sec. It says it's going into PE as soon as you stomp the pedal, which is what I want. The problem is it isn't going full PE rich right away. Adding to the AE seemed to help knock the AFR down quicker, but there's something else going on.

    Could there be a Catalytic enrichment I'm not seeing? Maybe this is why 2nd and 3rd gear are richer, down around 12.0 AFR like I want. In reality, VE may be lean because no Cat enrichment yet in 1st gear? This gets me back to the Desired AFR dumb look. You can see it right in the screen shot I posted in the first post. The red line along the bottom is the Desired AFR. When the throttle is mashed (blue line) it goes into PE, but the red line doesn't make any significant moves going from CL to PE. If the Desired AFR output a meaningful number, it would be much easier to tell if the ECM is richening up, beyond PE AFR, for something like a catalytic.

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