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Thread: Weird WOT flex fuel issue. Transient issue maybe? Please help

  1. #1
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    Weird WOT flex fuel issue. Transient issue maybe? Please help

    Ok so I got all of the main parameters changed and set for the ethanol sensor to work and all of that is working well.. the issue I'm having is when I go WOT, if I roll on to the gas everything seems fine and actual lambda follows commanded just as it should. When I do more of a stomp to WOT, actual vs commanded goes opposite. commanded goes to .79ish and actual shoots up to 1.22ish lambda. There are some blend tables in the transient tab that were all 0s and I populated them with ones I found from a Holden file. Maybe that's the issue? The truck 6.2 file doesn't seem to have those tables but I do have the flex timing table from the truck file

    I have some screenshots of the tables I think are causing this problem and another one of the problem happening in a log.

    I can upload my tune and full log in a few hours.

    You can see on the log pic that the first time I go WOT it goes lean but then when I roll on the throttle right after, it seems to work just fine.

    I usually just end up figuring this stuff out, but I'm really stumped on this one.

    Car is a 2011 Camaro ls3 N/A basic boltons

    Log WOT.PNG

  2. #2
    Tuning Addict 5FDP's Avatar
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    Is de-soot mode still enabled in the tune file?

    If it is, disable that see if it gets any better.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

  3. #3
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    De soot mode is disabled. Everything on 91 Oct is fine and working great so it got something to do with flex fuel tables somewhere.

    Update:. Just looked at another log and this problem only happens as soon as it goes past 4000rpm. Actual lambda matches commanded up to 4000rpm then it starts climbing fast. If I roll on the throttle up to 4k it will do the same thing but run way leaner to where it cuts off and stumbles.

    I don't think this is a VVE or MAF issue since it works fine on 91oct but I'm new at this so I don't know.

    edit: Here is my Tune file and the logs that show whats happening. This is very repeatable, I can go WOT at lower rpm and it will act normal.. within the same pull, it will start leaning out as soon as it hits 4k rpm. I had a couple of flukes where it actually went full lean (2.0 lambda) at WOT. Thought it may be a fuel pressure issue but it doesn't look like its dropping enough to cause that. INJ. duty cycle seems fine too.

    flex WOT lean 4k+.hpl
    flex low rpm WOT ok.hpl
    Rev 6-19-flex 1.hpt
    Last edited by SQUEEGIO; 06-09-2019 at 09:56 PM.

  4. #4
    Senior Tuner SultanHassanMasTuning's Avatar
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    you will need to enable your flex under fuel system, car will act weird with it disabled.
    E-tuning/remote Tuning Sultan@mastuning.net Follow @MASTUNING Contact/Whatsapp +966555366161
    [URL="http://www.mastuningsaudi.com"]

  5. #5
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    Alright thanks!
    I missed that. It says it's just for sensor diag but it's enabled now and will try it this afternoon.

  6. #6
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    Ok so now after loading the tune with the sensor diag enabled, warmed up the car and went for a test drive and the issue continues. I did however take a closer look at the log and saw something odd with my injectors. The screenshots show this but basically, right as it starts going lean at 4k rpm the injector flow rate drops while duty cycle and pulse width rise right as the lean condition happens.

    Stock ls3 injectors but they don't seem to be maxed out. I think max duty cycle I've seen was 60%
    This is all with only e50 BTW.

    This is the latest log:
    flex WOT lean.hpl

    injectors before 4k.jpg
    injectors after 4k.jpg
    Last edited by SQUEEGIO; 06-10-2019 at 07:33 PM.

  7. #7
    Senior Tuner SultanHassanMasTuning's Avatar
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    try thisRev 6-19-flex 1 test.hpt

    adjusted OL flex and maf mode
    E-tuning/remote Tuning Sultan@mastuning.net Follow @MASTUNING Contact/Whatsapp +966555366161
    [URL="http://www.mastuningsaudi.com"]

  8. #8
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    Thanks, I'll try that after work. If the problem is still there, I'm going to check & clean the MAF and maybe disconnect the battery for an hour or so.. maybe something went crazy when I had the ECU disconnected while installing the flex fuel kit. Do you recommend a MAF straightener seeing how choppy my MAF is?

    Also for the open loop alcohol blend, if I'm going to run e70 99% of the time, will having "1" from 50 and up make it easier to adjust fueling later on or just let it sit how you have it right now and play with the alcohol PE untill I get my desired fueling with e70?

    I noticed my stock tune alcohol PE is pretty lean in the lower rpm, should I follow that pattern?

    Thanks for the help so far. Certainly makes this a lot less stressful when you can bounce ideas off each other.

  9. #9
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    Quote Originally Posted by SultanHassanMasTuning View Post
    try thisRev 6-19-flex 1 test.hpt

    adjusted OL flex and maf mode
    WOW! I found it! I mean.. YOU found it! lol

    after comparing my file with the one you revised, I noticed you had a few more adjustments than just OL flex blend table and smoothed out a dip I had in my MAF table. I went ahead and made all of the changes you had because they made sense, but one of them stood out. Injector gain was set to enable on mine and disabled on yours... I then checked against my stock tune and what do you know! it was disabled there too. The description literally says: "WARNING- on some operating systems this may cause high RPM operation problems" I checked the tune history and found where I had accidentally switched it to enabled the day I installed the flex fuel sensor. I must have been in a hurry or something.

    Stupid mistake but that's how I learn I guess. Thanks again for helping out and taking the time to check things out.

  10. #10
    Senior Tuner SultanHassanMasTuning's Avatar
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    your welcome man...
    E-tuning/remote Tuning Sultan@mastuning.net Follow @MASTUNING Contact/Whatsapp +966555366161
    [URL="http://www.mastuningsaudi.com"]