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Thread: CALC.VET Struggles, VE Values Don't Seem Sane

  1. #21
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    Quote Originally Posted by joecar View Post
    +1 what statesman said...

    You must run MAF only in order to be able to calculate VE (otherwise you're calculating VE from VE rather than from MAF).
    Man I'm batting 1000. I should have also consulted this thread.

    https://forum.efilive.com/showthread...-Summary-Notes

    I'm glad you guys caught that. I'll check back in after my next logging session.
    1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
    1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
    2004 Corvette Z06 with longtubes.

  2. #22
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    I can't make this up. Earlier today I set B0120 to 400 (or so I thought) and B3313 to 140 (successfully) and proceeded to waste my time with a good 20 minute log. Looking over the tune now, B0120 is magically still at 4000.
    1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
    1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
    2004 Corvette Z06 with longtubes.

  3. #23
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    Quote Originally Posted by Supercharged111 View Post
    Doh! I forgot you like MAF only and DFCO disabled.
    It has to be in MAF only mode for CalcVET... but I think you now understand why.

    Yeah, I like DFCO disabled for tuning... it's a lot easier to work on fueling when the fueling is working.


    Quote Originally Posted by Supercharged111 View Post
    Was there anything else?
    Yep, here's my Christmas wish list for your next log...

    MAF Frequency
    MAF airflow
    TP
    RPM
    MAP
    ECT
    IAT
    GM Volts
    Short term fuel trims
    Long term fuel trims
    Front O2 sensors
    Knock Retard
    Wideband (make sure it's calibrated)

    You can log whatever other shit you want (I don't care about channel count), but make sure that everything in my list is being logged.

    Try to get a good mix of driving in the log. I don't care about WOT pulls yet... I just want to see how bad the fueling is and I can see that from normal driving. Get me at least 12,000 frames on a fully warm engine.

    Post your log and also post the actual tune file used to make that log.

  4. #24
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    Alright I'm sold. Using VE to calculate VE is a bad idea. MAF is about +/- 3% according to the SELBEN (PE fueling was only a couple tenths lean). I know you said no WOT, but, I got some anyway. MAF only the truck is less quirky, so that's encouraging as I have not touched the transient fueling on this truck. This is not the truck you've helped me with before, so it should look different. I haven't touched the tune yet, so what's below is what's still on the truck and likely what I'll drive to class in tomorrow seeing how it's actually better this way.


    Dually Edwards calcvet4.efi

    Edwards calcvet V2_MAF DFCO disabled.ctz

    I see advance dropping when I think it shouldn't. It just randomly drops from 38 to 13 with steady throttle. Speaking of steady throttle, when it comes time for the read deal I think I'm going to hook up the trailer. I can't hold it for but a couple of seconds before it goes from 50 to speeding ticket in OD and even the damn bumps in the roads here get my foot kicking back and forth a bit. Truck is stiff as a. . . nahh my mind went right in the gutter on that one. I rarely drive this empty and I never DD it so this is an adjustment. I just hope I got what you were after and there isn't anything weird going on like with my other truck. After this one is right I suspect I'm going to go back to stock VE and stock transients on the 1500 to just start with a clean slate. I'm beginning to wonder if I calculated VE with VE on that one back in 2017. . .
    1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
    1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
    2004 Corvette Z06 with longtubes.

  5. #25
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    Quote Originally Posted by Supercharged111 View Post
    MAF only the truck is less quirky, so that's encouraging as I have not touched the transient fueling on this truck. This is not the truck you've helped me with before, so it should look different. I haven't touched the tune yet, so what's below is what's still on the truck and likely what I'll drive to class in tomorrow seeing how it's actually better this way.
    I run my own vehicle permanently in MAF only mode. I just have my VE table close in case I ever have a MAF failure, but I don't spend too much time adjusting it.

    The MAF is a sensor that measures the actual airflow... you can't get better than that. Learn to love the MAF.


    Quote Originally Posted by Supercharged111 View Post
    I just hope I got what you were after and there isn't anything weird going on like with my other truck.
    Yeah you got what I asked for... but I'm getting old and I forgot a couple of things, so on your next log I'd like you to also log VSS and Commanded AFR.

    Your fueling doesn't look too bad, but what does look bad is your voltage.... it's too low. You've got 12.5v dropping down to 12.0 at WOT. You need to fix that. I recently blew my alternator because my main wire from the alternator to the battery had corroded and since my tune was good I haven't bothered to log my car in a few years, so I didn't know my voltage was dropping.

    Get your voltage fixed and then make a new log and remember to include those things I forgot to ask for before.
    Last edited by statesman; October 6th, 2021 at 02:53 AM.

  6. #26
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    I've always loved the MAF, and I think it's because it covers up my mistakes in VE. I just put a multimeter on the battery at an idle and I'm getting 13.8. At the tail end of my log I was idling at 12.5-12.7, hopefully it's something simple. I think I'll check grounds first and bump EFILive against my meter real time as well. MAF only never really occurred to me as being a viable thing, but now it sure is tempting now. But I also want to get better at fixing VE, and I think I found something that will help: tweaking VE 2D. I saw the picture of it in Shawn's post and it looks easier for me to digest when I'm forced to handraulically change stuff as Joe put it. I can usually nail a couple RPM points top to bottom with 50+ cells and sometimes even the 1 load point as well. With the trailer I expect my odds here will be really good. I think I'll sneak in 3% at the very top of the MAF before I go out again too. That should have me about spot on for PE AFRs. I'm thrilled with how the truck acts MAF only.
    1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
    1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
    2004 Corvette Z06 with longtubes.

  7. #27
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    Well something is up, I just observed 14.5V at the battery and 13.2 on EFILive, so as far as I can see 2 things are happening: 1 there's a significant voltage discrepancy between the PCM and the battery and 2 there's potentially some sort of heat related degradation. I say potentially because I'm used to seeing mid-high 13s on my 1500 when checked at the battery. Priority #1 is to ID the discrepancy in EFILive vs battery voltage. C'mon, just be an easy ground.
    1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
    1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
    2004 Corvette Z06 with longtubes.

  8. #28
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    So I've been away from the truck a couple of weeks travelling from coast to coast essentially. On the way I swung by my 1500 which used to suck on startup after the initial fire. I disabled VE on it and lo and behold 99% of the quirks are gone! So apparently I've been correcting VE with VE for some time now. I'm headed back to the dually now and will address the voltage issue upon my return so I can press forward with further cleaning up the tune.
    1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
    1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
    2004 Corvette Z06 with longtubes.

  9. #29
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    The ECM has it's own voltage measurement circuit which mat/will differ in accuracy/quality compared to a proper voltmeter/dmm.

    But, having said that, do check your connections, check for voltage drops in case you have bad connections/wires.

  10. #30
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    Quote Originally Posted by joecar View Post
    The ECM has it's own voltage measurement circuit which mat/will differ in accuracy/quality compared to a proper voltmeter/dmm.

    But, having said that, do check your connections, check for voltage drops in case you have bad connections/wires.
    What have you observed in terms of voltage differences between a DMM and what the PCM tells you? I intend to add a substantial ground strap that I suspect does not exist between the engine and frame, then double check my Lextech pinouts for power/ground sources to put eyes/DMM on to verify their condition. I'm basically looking for a limit to sanity checking my due diligence on the powers and grounds for the PCM as it seems the alternator is doing its job based on my voltage readings with engine running at the battery.
    1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
    1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
    2004 Corvette Z06 with longtubes.

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