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Thread: Adjustable ETC pedal to non-adjustable

  1. #1
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    Adjustable ETC pedal to non-adjustable

    Sorry if this has been asked before, but I couldn't find any relevant information via search functions.

    Issue: Swapped an '04 drive train from a Yukon (LQ4/4l60E) into a 90 Chevy truck. The PCM is flashed with the original 04 yukon with adjustable pedal according to vin. Obviously I cannot use the adjustable pedal, so I used the pedal/APP assembly from a 6.5 turbo diesel and repinned the APP connector to match the '04 TAC module wiring. Everything works, EXCEPT: TPS value reads 100% WOT at about 66% APP travel since the adjustable pedal assembly is a short mechanical throw in comparison to the fixed pedal throw of non-adjustable pedal. I'm almost 100% sure this is my issue, as my scan file shows 150% APP with pedal on floor.

    My question: is there a way to flash a different OS segment into the PCM for a non-adjustable pedal configuration to correct this? My other option is to fabricate a mechanical stop to the pedal assembly, but this is more of a bandaid in my opinion.

    Thanks in advance for any input/advice.
    Last edited by jglew82; 03-27-2019 at 09:09 AM.

  2. #2
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    Bump... Still having this issue and I'm afraid to mess with ETC tables or segment swap without any guidance.

  3. #3
    Tuning Addict blindsquirrel's Avatar
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    Can you just use the fixed-pedals '04 Yukon APP (15264643)?

    EDIT: Wait, there's two numbers with the same application notes, the second one is 15177923 - the same as used on '04 2500 6.6 TDs... is that the one you already have?
    Last edited by blindsquirrel; 03-27-2019 at 07:54 PM.

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    The TAC and pedal that I bought with the engine/trans was a fixed pedal from an '04 something-or-other, but not from this vehicle. I tried the actual pedal assembly that I got, and I had the same results.

    What I have now is a pedal from a '97 6.5 Turbo diesel since it is a direct fit for the 88-98 GMT400. The only difference was the wiring at the APP. I swapped the pins at the APP to match the '04 APP signal, bench tested before installing, and it worked the same way. I am going to try to do a "write-entire" from a vehicle I know has a fixed pedal and see if that corrects my issue. That's the only other way I can think of that will solve this. Other than the plug-and-play cruise control integration that I love, I am really kinda wishing I had gone DBC.

  5. #5
    Tuning Addict blindsquirrel's Avatar
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    The electrical differences when using the 'wrong' pedal is what will cause headaches, adapting the mechanical mounting to use the 'correct' pedal is the easy part.

    If your only issue is the over-travel thing I'd say you got extremely lucky. If you're happy with everything but that just fab up a travel limiter and set it to show 95-100% at full pedal and call it done. That's no more of a band-aid than using the wrong APP just because it's easier to bolt in, is it?

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    Quote Originally Posted by blindsquirrel View Post
    The electrical differences when using the 'wrong' pedal is what will cause headaches, adapting the mechanical mounting to use the 'correct' pedal is the easy part.

    If your only issue is the over-travel thing I'd say you got extremely lucky. If you're happy with everything but that just fab up a travel limiter and set it to show 95-100% at full pedal and call it done. That's no more of a band-aid than using the wrong APP just because it's easier to bolt in, is it?
    I see what you're saying here, but mounting the "correct" pedal in this case would be impossible since it was the adjustable one - it simply won't fit. Besides, the APP's for adjustable and non-adjustable are the same. In addition, the APP from the 6.5 is electrically the same; I tested this way before I decided to install it.

    I'll try your advice with a limiter and see how I like it . It's kind of a pain to drive (but also fun) right now because the pedal is so touchy, which may be caused by the shorter length of the lever on the pedal itself.

    Wow, swaps are fun!

  7. #7
    Tuning Addict blindsquirrel's Avatar
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    Oh, I know you can't just adapt in the adjustable pedal version. But, have you checked it with that pedal plugged in? Does it stop at 100% with no other changes?

    Most of the nightmares with pedal-swapping are when somebody uses a different pedal than what the combo came with because 'it's easier'... your mention of having to re-pin the connector was a red flag. Still is kinda.

    I've looked at the '04 Yukon files in the repository, taken the VINs from those files, and plugged them into TIS2000 to look at the factory calibrations. The only difference between them is for 'fuel system' which, when those files are opened in Editor, come down to different fuel tank size. None of the other cals for other systems are different, and none of them have selectable options for adjustable or fixed pedals. Do you know for a fact that there is an OS difference between adjustable and fixed to account for your issue, or just a suspicion?

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    Quote Originally Posted by blindsquirrel View Post
    Oh, I know you can't just adapt in the adjustable pedal version. But, have you checked it with that pedal plugged in? Does it stop at 100% with no other changes?

    Most of the nightmares with pedal-swapping are when somebody uses a different pedal than what the combo came with because 'it's easier'... your mention of having to re-pin the connector was a red flag. Still is kinda.

    I've looked at the '04 Yukon files in the repository, taken the VINs from those files, and plugged them into TIS2000 to look at the factory calibrations. The only difference between them is for 'fuel system' which, when those files are opened in Editor, come down to different fuel tank size. None of the other cals for other systems are different, and none of them have selectable options for adjustable or fixed pedals. Do you know for a fact that there is an OS difference between adjustable and fixed to account for your issue, or just a suspicion?
    Unfortunately I don?t have the adjustable pedal. The place I bought the lift out from gave me an ?04 tac and fixed pedal. I tested that one and it still read 150% at full swing.

    That is good info, as I don?t have access to TIS, so I had no idea if there were any actual differences - it was indeed a strong suspicion I had.

    I?m gonna deep dive into my current APP and take a lot more readings and see if I can find something I somehow missed. I put the 2 factory EWD?s next to each other to determine the correct pinning of the 6.5.

  9. #9
    Tuning Addict blindsquirrel's Avatar
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    Can you post your tune?

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    Quote Originally Posted by blindsquirrel View Post
    Can you post your tune?
    Yeah for sure. I?ll post that and a scan when I get to the house tonight. I really appreciate your input and looking through TIS for me.

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    Here is my current tune. My latest scan didn't show anything relevant, but I can do a new scan later if needed.
    Attached Files Attached Files

  12. #12
    Tuning Addict blindsquirrel's Avatar
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    OK, I've extracted the VINs from the 9 available tune files (there are 11, but one's a duplicate and one's an 8.1L), pasted them into TIS and looked at the segments included for each, and there are only minor differences (trans cal - 'updated calibration to address customer complaint of second gear start', or fuel system - which is tank size and/or flex fuel). Though, this is a small sample size of only 9, I guess it's statistically possible that ALL of these VINs were built with adjustable pedals and that's why a difference doesn't show. Can't rule it out but I think that's unlikely.

    Question: do you know if it's possible to use the '04 APP sensor on the '94 (I'm assuming) diesel pedal assembly? I looked at pics and the mounting flange, bolt holes, shaft keying look the same, but the connector boss is different and I can't tell if it will hit something (it sticks out off the backside on the '04s, the '94s are flat across the back). You've had the parts in your hand, you'd know better than me. Check the pics for reference:
    https://www.rockauto.com/en/catalog/...on+sensor,5061
    https://www.rockauto.com/en/catalog/...on+sensor,5061

    I'm beginning to think a travel limiter might not be a band-aid at all, it might be the proper fix. If the sensors are electrically the same inside the difference would have to be down to just the travel distance of the mechanical parts which calls for a mechanical fix, not software or electronics.

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    Did you ever resolve this in your tune? I'm seeing the same exact issue and have tested with two pedals, one '04 silverado and one from a 6.5 Diesel as you've tested with. Both show the same exact over-percentage. I hooked up to my '05 suburban and it doesn't have that issue, although it does have the adjustable pedal.

    I've seen several threads on this so I'm hoping someone has come up with a way to resolve it in the tune?

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    Quote Originally Posted by xEtherealx View Post
    Did you ever resolve this in your tune? I'm seeing the same exact issue and have tested with two pedals, one '04 silverado and one from a 6.5 Diesel as you've tested with. Both show the same exact over-percentage. I hooked up to my '05 suburban and it doesn't have that issue, although it does have the adjustable pedal.

    I've seen several threads on this so I'm hoping someone has come up with a way to resolve it in the tune?
    Nope, the issue is still there. I've been daily driving this thing for a long time now, so I've just gotten used to it. I think the solution might be to write entire a file from an '06 like what was said in the other thread.

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    Quote Originally Posted by jglew82 View Post
    Nope, the issue is still there. I've been daily driving this thing for a long time now, so I've just gotten used to it. I think the solution might be to write entire a file from an '06 like what was said in the other thread.
    For me, that means buying more credits to support an '06 which is not going to happen

    I'm going to play around with a hardware travel limiter to see how much travel I get while not exceeding 100%. Another idea I have is to just add some resistors in series and parallel in order to adjust the output voltage. I haven't been able to log the actual seen voltage though (just shows 0v in the scanner software) so I'm not 100% sure that would be a legit fix.

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    Did you happen to find a solution that didn't require another $100 worth of credits and may or may not work? I've looked at several DBW swapped vehicles and they all seem to have the same issue. It sort of makes them annoying to drive.

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    Quote Originally Posted by wlwarnke View Post
    Did you happen to find a solution that didn't require another $100 worth of credits and may or may not work? I've looked at several DBW swapped vehicles and they all seem to have the same issue. It sort of makes them annoying to drive.
    In my case I used a diesel pedal with the same issue as the adjustable. In the end I found that when I mounted it, it bottomed out right at 100% so I'm just going to run it. Still seems to have plenty of travel.

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    I ended up swapping to DBC. Got sick of the REP's and pedal travel issues. MUCH happier now, and as an added bonus, I can finally have AC clutch control/idle bump through the PCM with the 0411.