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Thread: 1996 Chevy 7.4L - 0411 swap

  1. #1
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    1996 Chevy 7.4L - 0411 swap

    Hello,

    New member here from GMT400.com, I do notice a couple familiar names from there on here.

    I recently went to an 0411 on my 1996 Chevy K2500 with a 454 and a 4L80E, I received the pinout from LexTech, as well as his kit with the 0411 and connectors.
    I followed his pinout to a T, although I did make a few mistakes such as not adding in the wire for the EGR and not properly putting the VSSB wires together, but both of these have been corrected.

    It idles like crap now, it used to idle 750-800 RPMs, now it's 550-600, shakes like it's misfiring, wants to stall out when I put it in gear, and it's throwing 3 codes, a P102, a PO341, and the P1336 which I expected the crank relearn code.
    I've had someone who's done the swap tell me the CMP code could be related to the CKP which does make sense, but I'm lost on the MAF code; I did clean it but it's still running rough.
    I've checked my pins 4 times now, and I'm about to check them again, anyone got any suggestions? I don't really have a means of datalogging, I've got a crappy Harbor Freight scanner that shows me some of the information but not a lot.

  2. #2
    Advanced Tuner Obsolete489's Avatar
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    Quote Originally Posted by BNielsen View Post
    Hello,

    New member here from GMT400.com, I do notice a couple familiar names from there on here.

    I recently went to an 0411 on my 1996 Chevy K2500 with a 454 and a 4L80E, I received the pinout from LexTech, as well as his kit with the 0411 and connectors.
    I followed his pinout to a T, although I did make a few mistakes such as not adding in the wire for the EGR and not properly putting the VSSB wires together, but both of these have been corrected.

    It idles like crap now, it used to idle 750-800 RPMs, now it's 550-600, shakes like it's misfiring, wants to stall out when I put it in gear, and it's throwing 3 codes, a P102, a PO341, and the P1336 which I expected the crank relearn code.
    I've had someone who's done the swap tell me the CMP code could be related to the CKP which does make sense, but I'm lost on the MAF code; I did clean it but it's still running rough.
    I've checked my pins 4 times now, and I'm about to check them again, anyone got any suggestions? I don't really have a means of datalogging, I've got a crappy Harbor Freight scanner that shows me some of the information but not a lot.
    I don't there is a way to tag in here, but hopefully Oleblu chimes in with some ideas, he's pretty knowledgeable.
    2000 K2500 - 489 CI Vortec w/ comp XE270 cam - 0411 swap and rear mount turbo
    1972 M35a2
    2011 LML Duramax

  3. #3
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    Save money and buy the software. Pro version hardware if possible. The computer would be happier with a crank relearn. The stock van tunes idle is pretty low in that range. Your positive the egr is working correctly? Maybe unplug it and see if it clears up the idle. We need logs, And your stock tune file. It sucks to diagnose by stabbing in the dark. I would focus on codes. Which codes numbers where present?
    Last edited by Oleblu; 04-10-2019 at 07:29 AM.
    97 ext cab short bed silverado 5.7 411 swap, edelbrock 29135 intake, lightly ported 906 heads milled .035 thou. factory press in rocker studs & rockers, comp 787 retainers & stock locks, ls6 springs. Comp cams 08-503-8 T56 swap

    86 SWB crate vortec 5.7/th350 The wife's truck

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    I'll try to upload my logs I got from my Harbor Freight scanner, they're not the best but it'll at least be something.
    I had the EGR unhooked on the first start, then added the wire per Lextech's instructions only to find out it made no change.

    I've got someone who is going to attempt to help me with sorting everything out, I'll see if he can possibly try to pull the tune off if the issues continue.
    Codes are
    P102
    PO341
    And P1336, which I believe is the crank relearn,

  5. #5
    Advanced Tuner Obsolete489's Avatar
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    Having it looked over by Mangone is going to be the best chance at figuring this out. When you disconnected the MAF, did it throw anymore codes?


    Oleblu, his ltfts were both ~10%, also we had him disconnect his MAF and try driving it. No luck.
    2000 K2500 - 489 CI Vortec w/ comp XE270 cam - 0411 swap and rear mount turbo
    1972 M35a2
    2011 LML Duramax

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    check the wires for the cam sensor and crank sensor. I'm assuming your cam retard was dialed in beforehand? I would say its probably wiring related, seeing as the harness was physically moved, tugged, pulled on. check for proper voltage and continuity at the cam sensor connector. same with the crank sensor and Maf. let us know the results. unless the tune file is corrupt I would assume wiring is the issue.

    on my personal truck I ended up with bad wires in the harness feeding voltage to the Maf and cam sensor. Good luck and let us know what you find.
    97 ext cab short bed silverado 5.7 411 swap, edelbrock 29135 intake, lightly ported 906 heads milled .035 thou. factory press in rocker studs & rockers, comp 787 retainers & stock locks, ls6 springs. Comp cams 08-503-8 T56 swap

    86 SWB crate vortec 5.7/th350 The wife's truck

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    @Obsolete489 - It just threw the same code when it was plugged in, "MAF low circuit bank 1" or something along the lines of that, the CMP code was the same "low circuit" reading.
    I hope Mangone and I can figure it out. I can't get to the truck today due to work running over and prior commitments, but hopefully after a salvage yard run tomorrow I can dig in and try to get it figured out.

    @Oleblu - How did you resolve that issue? Did you just find a new power source for the sensors or bypass the damaged wire and run a new length?
    Here's some data





    A couple other issues I forgot to add, the truck will not start unless the fuel pump fully primes; which is used to be I could fire it off as soon as I turned the key, and the truck runs super rich when it does want to, I assume from the MAF not reading correctly?

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    I ran new wires through the harness, kept it simple finding an extra pink wire (ignition switched source) to tap into. I aslo had to run new wires from the sensors to the pcm. for cam and maf signal as my entire harness was damaged from rubbing the top of the bellhousing. That's potentially another place to check the factory wiring for issues. Is the truck stock? Aside from the pcm swap.
    97 ext cab short bed silverado 5.7 411 swap, edelbrock 29135 intake, lightly ported 906 heads milled .035 thou. factory press in rocker studs & rockers, comp 787 retainers & stock locks, ls6 springs. Comp cams 08-503-8 T56 swap

    86 SWB crate vortec 5.7/th350 The wife's truck

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    Quote Originally Posted by Oleblu View Post
    I ran new wires through the harness, kept it simple finding an extra pink wire (ignition switched source) to tap into. I aslo had to run new wires from the sensors to the pcm. for cam and maf signal as my entire harness was damaged from rubbing the top of the bellhousing. That's potentially another place to check the factory wiring for issues. Is the truck stock? Aside from the pcm swap.
    Yeah, aside from a true dual exhaust it's bone stock, it's got a few upgraded factory spec parts like 5O Motorsports 19lb Blue Knight injectors, but other than that it's stock as a rock mechanical wise.
    I do suspect that MAF and CPM are somewhat related, when I first bought the truck I had injectors, intake gaskets, and a whole bunch of other stuff done, my mechanic said it was throwing a code for the cam position sensor due to the pigtail being damaged (replaced with a BWD pigtail and connector), and he also noticed something odd with the MAF on his Tech II scanner.

  10. #10
    Since no one has really asked this question, i will. Doesnt the truck run fine when you have the black box in ? No MAF or CMP codes or stumbling, just runs like nothing happened? I believe you mentioned you had swapped the black box in one the first go round to test that it wasnt a wiring issue.

    Yes, i plan on going down there saturday to suck the tune out and do some comparing. i should be able to make a matching tune and use it in my 0411 and plug it right in as long as VATS is disabled, correct? And that really only effects a stock radio or is that a BCM/Ecu comm that VATS effects?
    1997 Chevrolet K2500 ECSB, 0411, 454, headers w/ Exhaust, MSD, 28lb injectors "Biggin"

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    Quote Originally Posted by Mangonesailor View Post
    Since no one has really asked this question, i will. Doesnt the truck run fine when you have the black box in ? No MAF or CMP codes or stumbling, just runs like nothing happened? I believe you mentioned you had swapped the black box in one the first go round to test that it wasnt a wiring issue.

    Yes, i plan on going down there saturday to suck the tune out and do some comparing. i should be able to make a matching tune and use it in my 0411 and plug it right in as long as VATS is disabled, correct? And that really only effects a stock radio or is that a BCM/Ecu comm that VATS effects?
    The truck ran fine with the Black Box, no codes or anything, idled normal and drove fine, a slight stumble but nothing serious.
    I had plans to go back to the black box but decided to wait after I went through all my pins and rerouted wires, which the truck ran fine after first start up the second time I pinned wires for the 0411, but the stumbling at idle and misfire progressively got worse from there, and like I showed you, I have all my wires marked and ran so I could double check them, should I try and go back to the black box to see if it really is a wiring issues?

  12. #12
    I think it would be more worth the while if you kept the 0411 in there for now and waited. Surely you've tried wriggling around the wires a bit while it's running to see if anything changes, right?

    We should be able to determine root cause while I'm there. We'll graph the MAF freq and everything as well. I have some tunes to compare with as well.

    Anyone have a few minutes to provide a screenshot of their MAF freq vs RPM or any other good data for me to work with while I'm down there?
    1997 Chevrolet K2500 ECSB, 0411, 454, headers w/ Exhaust, MSD, 28lb injectors "Biggin"

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    Yeah, that's one of the first things I tried doing was adjusting wires, both at the PCM and at the sensors. I rechecked the pins tonight, everything is right, I am a little confused regarding one of the EVAP wires, I may have gotten confused and accidently pinned it when it wasn't needed. I tried to meter the MAF and CPM sensors and connectors but ran out of daylight,

  14. #14
    Advanced Tuner Obsolete489's Avatar
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    I'll try to post a tune I did for a stock truck in the morning.
    2000 K2500 - 489 CI Vortec w/ comp XE270 cam - 0411 swap and rear mount turbo
    1972 M35a2
    2011 LML Duramax

  15. #15
    Advanced Tuner Obsolete489's Avatar
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    Main Tune - Airflow calibrated 12-1-18.hpt

    Didn't get to it right away this morning, I helped remote tune this truck. 100% stock with an 0411, used a wideband to tune VE and MAF. Hope this is what you were looking for Mangone.
    2000 K2500 - 489 CI Vortec w/ comp XE270 cam - 0411 swap and rear mount turbo
    1972 M35a2
    2011 LML Duramax

  16. #16
    It's helpful. I do appreciate it.

    I'm getting all of my files and junk in order and making sure my laptop has rebooted a few times and charged.
    1997 Chevrolet K2500 ECSB, 0411, 454, headers w/ Exhaust, MSD, 28lb injectors "Biggin"

  17. #17
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    Let me know how it goes, or if I can help in any way.
    2000 K2500 - 489 CI Vortec w/ comp XE270 cam - 0411 swap and rear mount turbo
    1972 M35a2
    2011 LML Duramax

  18. #18
    Well, so far we've used a tune that is basically a hodgepodge between my orig lextech tune and his, then bascially yours obsolete and we've had no results.

    However, while logging I noticed his MAF was not putting out ANY frequency signal at all. We have a spare coming and I'm about to try to backprobe with a meter to see if I can pick up any voltage/frequency from it while it's running.
    1997 Chevrolet K2500 ECSB, 0411, 454, headers w/ Exhaust, MSD, 28lb injectors "Biggin"

  19. #19
    Advanced Tuner Obsolete489's Avatar
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    Did you try swapping in your computer to see if that changed anything? Also maybe try failing the maf and put it in SD?

    Sounds like that's probably the issue.
    2000 K2500 - 489 CI Vortec w/ comp XE270 cam - 0411 swap and rear mount turbo
    1972 M35a2
    2011 LML Duramax

  20. #20
    Well, test MAF shows no frequency. Checked the wiring and we have a good 5v signal to MAF, good ground, we have .4ohm of resistance on the signal feedback wire but we still are not seeing via the scanner any feedback. It just shows 1.1g/s and 0hz.

    I'm stumped, this is going to take some googling.
    1997 Chevrolet K2500 ECSB, 0411, 454, headers w/ Exhaust, MSD, 28lb injectors "Biggin"