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Thread: Ls obs ac signal??

  1. #1
    Join Date
    Oct 2013
    Location
    Jacksonville, AR
    Posts
    63

    Ls obs ac signal??

    I've had my truck swapped with a h/c/i 5.3 for a while now and have driven it everywhere with no real issues....aside from these 2 and I've had enough of just dealing with it.I utilized the Holley R4 swap bracket with truck spacing, allowing me to keep all of my brand new (at the time) '90 AC stuff intact.

    1-I never did anything with the wiring to inform the PCM that the '90 compressor was kicked in, because in previous swaps I've done, I never had to. The motor would detect the load, compensate, and life was fine. However with MY swap, my setup decides that it can't handle the load when the AC is on and starts to stumble on itself and eventually killing the motor at parking lot speeds/idle, unless I manually bump the idle with my foot. What information/hardware do I need to find to allow the 0411 to automatically bump the idle when the compressor is engaged?

    2-This one actually makes me angry....My front drive accessories keep throwing belts and tearing stuff up; Power steering lines(@125mph+ one time), upper radiator hose, and mostly just keep on tearing up my underhood insulation! I've checked with an alignment laser, tried different belt sizes (while keeping the tensioner in the designated hash marks), and different brands of tensioners. Nothing I have done seems to have worked so far. The issue is that the belt flings off when I bounce of the rev limiter or just snap off the throttle from high RPM. Is this as simple as throwing on a manual tensioner or do I need to look else where for my setup?

    Thanks ahead of time for helping me out!

  2. #2
    Quote Originally Posted by Jmac527 View Post
    I've had my truck swapped with a h/c/i 5.3 for a while now and have driven it everywhere with no real issues....aside from these 2 and I've had enough of just dealing with it.I utilized the Holley R4 swap bracket with truck spacing, allowing me to keep all of my brand new (at the time) '90 AC stuff intact.

    1-I never did anything with the wiring to inform the PCM that the '90 compressor was kicked in, because in previous swaps I've done, I never had to. The motor would detect the load, compensate, and life was fine. However with MY swap, my setup decides that it can't handle the load when the AC is on and starts to stumble on itself and eventually killing the motor at parking lot speeds/idle, unless I manually bump the idle with my foot. What information/hardware do I need to find to allow the 0411 to automatically bump the idle when the compressor is engaged?

    2-This one actually makes me angry....My front drive accessories keep throwing belts and tearing stuff up; Power steering lines(@125mph+ one time), upper radiator hose, and mostly just keep on tearing up my underhood insulation! I've checked with an alignment laser, tried different belt sizes (while keeping the tensioner in the designated hash marks), and different brands of tensioners. Nothing I have done seems to have worked so far. The issue is that the belt flings off when I bounce of the rev limiter or just snap off the throttle from high RPM. Is this as simple as throwing on a manual tensioner or do I need to look else where for my setup?

    Thanks ahead of time for helping me out!
    Did you get an answer or solution to your problem?
    If not, probably need to raise the idle a little

  3. #3
    Join Date
    Oct 2013
    Location
    Jacksonville, AR
    Posts
    63
    I have raised the idle up manually with the throttle body idle screw. This has helped the issue a little with the stumbling at idle with the A/C on. I still have an issue with the truck dying on me with the A/C on if in stop and go traffic.

    However as far as losing the belt at high RPM, I think I may have FINALLY settled this issue. I have changed my tensioner pulley to a Dayco 89003 unit. This pulley is has little flanges on either side that have kept the belt from rolling off the front of the pulley when the tensioner reacts to me letting off the throttle at high RPM or accidently hitting the rev limiter.

  4. #4
    Join Date
    Mar 2013
    Location
    Long Beach California
    Posts
    639
    Just a thought... could the tensioner pully be physically aligned front-to-back wise which the laser would tell you to be true/inline with other pullys BUT angled (probably downwards) as to allow the belt to creep forward and slip off? idk if that makes sense but idk how else to put it... I was having the same issue with throwing belts but mine was a front to back issue....i believe.....i think i fixed it....

    as for the ac input to the pcm, as far as i know AS OF NOW, there is no way to do it. This is due to the fact that the pcm receives this signal via serial data vs voltage. i read SOMEWHERE (ill have to look in my thread) that there was a POSSIBILITY that ONE tuning software could change how the pcm received the signal from serial data to voltage input but was never fully confirmed. this is what we would need. I want to say the software was Tunercats or something like that. but like i said, i believe this is a myth as this is still an ongoing issue. what swaps have you done previously that havnt had issues? from what ive read and personal experience, seems like the smaller motors are the ones that are having the AC-idle kill issue which i believe to be due to torque differences. my 6.0 most definately starts to stumble in idle situations and has died a few times unless i blip the throttle like you say. but for the most part it will compensate and be ok most likely because it has more torque than a 4.8/5.3
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