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Thread: 1985 Caddy Limo - Engine swap with transmission issues

  1. #16
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    Post Update

    First off thanks for the continued responses and offers for help, I'm feeling much less alone in this battle!

    I spent a good part of the day trying to sort out some of the above and here's where I netted out:

    Knock Sensors - Per the service manual, attached
    1. I tested both knock sensors and they came back within the correct resistance spec.
    2. I ohm tested the wires from both plug ends (each sensor plug to PCM connector) and they checked out ok.
    3. I put the car in key-on position, pulled off the PCM connector and tested the corresponding pin on the PCM itself for 5V and there was nothing. Then I plugged the connector back in and tested the same pin by using a piece of thin wire running down through the back side of the connector, still nothing.

    The service manual says there should be 5V. If not, there's a circuit short or it's a bad PMC.
    So that points to bad PCM?


    Scan9495 - Data logging

    Wow, this software is really great, I'll certainly make a donation! That said, for the life of me, I couldn't figure out how to record and save the transmission data. I checked the box in the transmission tab for dataloging, but i couldn't play it back. All of the datalogs I made today can be found here (the last one is probably the best): https://www.dropbox.com/sh/84hyxymk0...FtnKj3Rba?dl=0

    Because I couldn't playback the trans data I made a video (https://youtu.be/ARK0Uh2pCxs) which should match the last of the data files in the dropbox if you sort by date/ time. I apologize in advance for the video quality. I'll try to stabilize it later when my computer isn't acting up.

    The software seems to create two files (DLOG-trans... and DLOG-Save...). I can't open the "trans" file without getting a hex error. The "Save" files open but do not play back the transmission data. Confused yet? I am.

    Transmission Observations

    I jacked up the tail of the car and did the following:

    1. (not in video) When shifted in Park and key-on, I was able to use the Actuator screen feature to actuate all the solenoids one at a time, in both directions. Or at least, I was able to hear them all make a clicking sound.

    2. If you watch the video, towards the end, you'll see that I am able to use the command shift buttons to shift gears up and down successfully. You'll also see that sometimes I had to click more than once to get it to work, not sure if that's an indicator of anything.

    3. Manually shifting the transmission does NOT change the gears.

    Thoughts/ Questions

    Given that the knock sensor 5V output pin on the PCM does not work, I'm led to believe I may want to replace the PCM.

    I'm not sure what it means if I can command the transmission to shift up and down using 9495, but it refuses to shift manually.

    Is that a PCM problem? i.e. The PCM is not sending the proper signal to the transmission.

    Or the it a mencanical issue? i.e. The trans is in a mechanical state which will ignore an incoming signal.

    Any thoughts?
    Last edited by BlackBettyLimo; 10-13-2015 at 08:32 PM. Reason: Typos

  2. #17
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    Quote Originally Posted by lionelhutz View Post
    There are 2 solenoids that control the main shifting. They were referred to as A and B but then got called 1-2 and 3-4 to match the ODB2 convention. At any rate, the shift pattern is as follows.
    Code:
          A   B
    1st   X   X
    2nd   -   X
    3rd   -   -
    4th   X   -
    As you can see, if the A solenoid was stuck-on you'd get 1st and 4th gear, skipping any shifts into 2nd or 3rd gears. That pattern is also why "limp mode" goes to 3rd gear. No power to the solenoids and the transmission goes to 3rd gear.

    Now, I'd expect you have to be doing around 30mph or possibly more before the PCM would command a shift into 4th gear. The speed really depends on the tune.
    Thanks for this! I was paying close attention to these cells in Scan9495 because of you.
    If you watch the video I just posted you can see these cells in action.
    When I manually shift these cells/ solenoids both stay on. When I "command" it to shift up and down they operate as they should.
    Last edited by BlackBettyLimo; 10-06-2015 at 11:06 AM. Reason: Forgot to quote original post

  3. #18
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    Quote Originally Posted by lionelhutz View Post
    Just to further note, I did check 5 bins and the lowest 3-4 upshift speed was 29mph.

    Looking at your log and then a few of my old logs, the "Gear Num" in the left column of TTS is the actual commanded gear. Your log never changes from 1 so it's not even attempting to shift. In my old logs when I used TTS, that number would jump to the next gear and then I could see the rpm and slip rpm results due to the shift being commanded.
    Yes, the PCM is failing to send a command signal. Not sure why at this point. Electrical or mechanical?

  4. #19
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    Quote Originally Posted by dave w View Post
    If you want, you can ship me your PCM, I can then read and post the .bin file I read from the PCM.

    I only ask that you pay shipping, both ways.

    Send me a PM for my shipping address.

    dave w
    Thanks of the generous offer Dave, Much appreciated. Let's get some thoughts on my latest post before we move to that. Maybe I'm throwing time and money at a bad PCM at this point?

  5. #20
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    I think the problem might be related with the ParkNeutralPosition switch located on the shift lever.
    If it is not installed properlly the pcm will thinks the car is in P or N and will never attempt to shift.

  6. #21
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    Quote Originally Posted by kur4o View Post
    I think the problem might be related with the ParkNeutralPosition switch located on the shift lever.
    If it is not installed properlly the pcm will thinks the car is in P or N and will never attempt to shift.
    Is that switch not located in the transmission itself? As you can see in the video link above the trans data shows the gear selector moving, although it is not commanding a gear change.

  7. #22
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    It is located at the shift lever. It goes to pin C15 at PCM.
    You can check where those wire goes and see if it is connected somewhere.
    For the PCM to think it is in P or N the wire must be grounded.
    If the wire is in open state or not connected It is very possible an error is set and PCM is in some service mode.
    Last edited by kur4o; 10-06-2015 at 09:53 PM.

  8. #23
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    OK I just watch the video.
    The PNP switch is mostly related with IAC valve so it`s not very important for the not shifting problem.
    I just check could the trans solenoids can be manually commanded if the bin is for manual transmission.
    Answer is yes, so my final guess is, you have bin for manual transmission in the PCM.
    On the video everything look OK except for the transmission not shifting.

  9. #24
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    Quote Originally Posted by kur4o View Post
    OK I just watch the video.
    The PNP switch is mostly related with IAC valve so it`s not very important for the not shifting problem.
    I just check could the trans solenoids can be manually commanded if the bin is for manual transmission.
    Answer is yes, so my final guess is, you have bin for manual transmission in the PCM.
    On the video everything look OK except for the transmission not shifting.
    The guy who originally flashed the PCM though he could have made that error, so I sent it back to him and he confirmed all the correct specs and made sure he had a flash for an automatic transmission (he suggested that as a possible issue).
    I'm guessing he triple checked his flash this last time.

    I still need to go see about pin C15 next time I'm at the car, just for grins. No codes being thrown at the moment for that.

  10. #25
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    I'm certain I have the P/N switch C15 open and the brake switch C14 input jumpered to power and my transmission works.

    I recall something about the Manual/Auto flag that is identified in the $EE was wrong because it was giving the wrong results with some bins. I wouldn't turn-on the auto in a bin but rather start with an auto bin.

    I'd think the tuner would have pulled the bin, turned-off the stuff which was removed and then re-flashed the same bin.

  11. #26
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    Since you have a working cable, download winflash programm from tunercats here:

    http://tunercat.com/software/winflash/flash_setup.exe

    It is fully working demo version limited to one month of usage.
    Read the bin from your PCM and post it here.
    That way we can help you really fast.

  12. #27
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    Quote Originally Posted by kur4o View Post
    Since you have a working cable, download winflash programm from tunercats here:

    http://tunercat.com/software/winflash/flash_setup.exe

    It is fully working demo version limited to one month of usage.
    Read the bin from your PCM and post it here.
    That way we can help you really fast.

    Ah, great! Thanks,will do!

  13. #28
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    Quote Originally Posted by kur4o View Post
    Since you have a working cable, download winflash programm from tunercats here:

    http://tunercat.com/software/winflash/flash_setup.exe

    It is fully working demo version limited to one month of usage.
    Read the bin from your PCM and post it here.
    That way we can help you really fast.
    I was able to pull the bin file using Tunercat's Winflash as suggested, attached.
    What's the best way to view this file?

  14. #29
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    Quote Originally Posted by lionelhutz View Post
    I'm certain I have the P/N switch C15 open and the brake switch C14 input jumpered to power and my transmission works.

    I recall something about the Manual/Auto flag that is identified in the $EE was wrong because it was giving the wrong results with some bins. I wouldn't turn-on the auto in a bin but rather start with an auto bin.

    I'd think the tuner would have pulled the bin, turned-off the stuff which was removed and then re-flashed the same bin.
    Thanks for the input on C14/15!

    The guy who did my flash seems very competent so I'm guessing that outside of any major oversight his methodology is sound.

    Is there a way to find a OEM bin and compare the two files?

    If I do have to adjust the bin file, I should turn off anything related to Air Conditioning since the limo's AC controls will operate this independently of the PCM. This may fix my "fans-are-always-running on high" issue, based on some recent research.

    I should also turn off the VSS output signal.

    The fact that the pin on the PCM for the knock sensor circut doesn't register 5v is still of some concern...
    Last edited by BlackBettyLimo; 10-12-2015 at 08:59 AM.

  15. #30
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    I checked the bin.
    On eside part, the data is not defined properly on the current xdf files. It looks like tside is $ee and eside is $eeb or something else.
    The point is any change on the eside calibration will have unpredictable result.
    The best way will be to start with the latest bin for your application. Based on tis2web, your starter bin will have p/n 16200271.
    Unfortunatelly I could`n find it anywhere, so we need to pick you another bin similar to your application.

    Can you please post your final gear ratio and tire size so I can make you a suggestion.

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