Page 1 of 7 123456 ... LastLast
Results 1 to 15 of 104

Thread: 1985 Caddy Limo - Engine swap with transmission issues

  1. #1
    Fuel Injected!
    Join Date
    Sep 2015
    Posts
    59

    1985 Caddy Limo - Engine swap with transmission issues

    Meet Black Betty, a 1985 Cadillac Fleetwood Brougham Limo. My buddy and I bought/ rescued her from an LA "hair band" recording studio where, before had she broke down, she had been in service for the last 20 years as the official party car for such bands as Slayer, Ratt, White Snake, Aerosmith, and Bon Jovi.

    Like most party girls, she's pretty from afar, but far from pretty when you get up too close, or in daytime. Cheap paint, rust, broken sunroof, absolutely trashed interior. Everything you'd expect in a limo with real rock and roll history.

    Attachment 9596Attachment 9584
    We bought her for $800 (plus $600 in back registration penalties) on the bet we could get her in motion for a few more grand.

    We got two new batteries and replaced the rotted fuel lines and packed fuel filter, and darn if it didn't fire up. We limped around the block only breaking down twice. A tank of fresh gas, some spliced ignition wires (chewed by rats), general tune up, some speed runs to burn off the filth, and we had a wonderful party car that was always on the verge of overheating or breaking down.

    While willfully ignoring the mountain of cash it would take to transform this thing into an enjoyable vehicle, it became apparent that the current head gasket leak wasn't going to fix itself, so in an alcohol induced fit of inspiration we decided to pull the motor and rebuild it. For anyone who has ever attempted such a thing you can see where this is going already. The OEM motor was a 4.1L TBI V-8 pumping out an aggressive 135hp. 0-60 was under 30 sec, wet. Obnoxiously underpowered for the task at hand it took about an hour into the tear down to decide to just go ahead do an engine swap. The engine was a total mess and after much research on the webs we found that we'd just be meticulously rebuilding one of the worst engineered GM motors in existence.

    Attachment 9564Attachment 9597Attachment 9565

    Project funds are depleted and depression sets in. 1 year passes.

    After some springtime beer-based research, and based on new budget constraints, we decided to buy an $800 1994 Buick Roadmaster with an 5.7L LT1 that had an output of 280p/ 335 lb-ft, paired with a 4L60E transmission. This seemed to be just enough grunt to pull a bunch of "adults" trying to cling on to their youth. The test drive went well, however on the hour-long ride home I noticed some water temp surging and hard shifts in the transmission.

    6 months later and we finally get around pulling everything and scrapped the Roadmaster.

    Attachment 9569Attachment 9570

    I have zero fabrication skills so we found a guy that was going to help us with the engine mounts/ set pinion angle, etc. After putting us off for 4 months he decides to leave the country.

    5 more months pass.

    While we were waiting to find a cheap and good (pick two, right?) fabricator, we decided to rebuild the motor and have the transmission inspected. It didn't make much sense to install an engine with known issues.

    I had never rebuilt a pushrod motor before, and I'm a bit OCD when it comes to dirt, so it took me most of the summer just to clean the engine to be able to work on it. New water pump, oil pump, Optispark dist, main and cam bearings, rings, every seal I could find, de-carbonized, de-greased, heads were refreshed with valve job etc, etc. I didn't over-bore the cylinders, just deglazed with stones. The cam and crank were mostly in spec. I had hemorrhaged money on everything else so I decided to just let it be a loose engine. I figured I could run thicker oil, if necessary, and call it a day. It's not a hotrod and the mileage on it will be minimal.


    Attachment 9571Attachment 9572Attachment 9574Attachment 9582Attachment 9573Attachment 9579Attachment 9577Attachment 9578Attachment 9580Attachment 9588Attachment 9589Attachment 9586Attachment 9585Attachment 9587

    The engine rebuild took all summer, so in the meantime we got the transmission inspected/ refreshed. We were still waiting on a fabricator who wouldn't string us along or wasn't too busy. So the project sat for another 6 months.

    We finally got some help though a very talented and generous friend and after a few more months got it in the vehicle.

    Attachment 9591Attachment 9592Attachment 9593Attachment 9594Attachment 9595

    And now the transmission problem... more to come.
    Last edited by BlackBettyLimo; 10-06-2015 at 09:54 AM. Reason: typos

  2. #2
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,268
    Thanks for sharing, keep us updated.

    dave w

  3. #3
    Fuel Injected!
    Join Date
    Jun 2012
    Posts
    28
    Cool story!

  4. #4
    Fuel Injected!
    Join Date
    Sep 2015
    Posts
    59
    Well, to my general amazement, I was not only able to successfully assemble a motor, but the thing actually started up on first crank and idled like a champ. No oil leaks, no spun bearings, no overheating. High fives all around.

    Honestly, it's kinda an amazing feeling. If you haven't done it you should give it a try. Go slow, read the service manual a few times before you do the task at hand, and if you get in a bind, ask questions on forums and watch a youtube video or two (or 10, like I did).

    https://youtu.be/j22UILXOqbA

    So all excited like, we get her on the road, and she won't shift out of 1st gear, manually or otherwise.

    We had taken the trans to a reputable shop so we were fairly confident that it wasn't a mechanical issue. But as we researched the 4L60E (electronically controlled) transmission we realized that when we unplugged the transmission harness and drove the car, the transmission was not flipping into a proper "limp mode." In theory, when you pull the power from the transmission it should default to 3rd gear and you should be able to manually select 2nd gear, and that was not happening. We were stuck in 1st gear.

    We had also read on a forum that some people were able to spin first gear up to 3500 rpm, suddenly come off the gas, and feather it back in, and the trans would up-shift. We tried that, both while the trans had power and was unplugged, and this method worked in both instances. Ok, so, this now led us to believe that it may in fact be a mechanical problem. We pulled the trans and brought it back to the shop.

    While they were checking it out we tested the VSS module (seemed ok), we Ohm tested all the wires from the PCM plug to the trans plug (they checked out), and we made sure that the transmission was getting a full 12v in the ignition key-on and running positions.

    We also sent the PCM back to the guy who originally flashed it for us (to get rid of the digi-key requirement) and double checked the new/ different rear gear ratio and tire height he had set for the Caddy, and confirmed it was set for an automatic trans and not a manual one. It turns out some of his numbers were in fact off a bit and he re-flashed it to the new spec.

    The word came back from the transmission guys that they went ahead and rebuilt the valve body, fully inspected every single part, replaced 3rd gear (was worn), and said "at this point any issue that may occur isn't going to be a mechanical one." This refresh was no cost to us, and so I’m fairly confident that at this point it’s not a mechanical problem.

    We double checked all of our wiring and found that we had reverse wired the TCC wire to the brake switch.

    So with all this in mind, we put it all back in the limo, and wouldn't you know, the dang thing still won't shift out of 1st gear.

    The only change was when we now unplugged the transmission harness it did finally go into a proper limp mode (starts in 3rd gear and we could manually shift to 2nd). So I'm guessing there many have been some sort of mechanical issue originally after all.

    HOWEVER, this still doesn't explain why when the transmission has 12v of power going to it, it won't shift out of first gear.


    Now, up to this point we had been flying a bit blind. I had failed to pull the ALDL plug out of the Roadmaster and wasn't aware that there was software out there (aside from a GM tech tool) that could help diagnose some of this. We had no idea if the PCM was throwing relevant DTC codes at us or not.

    Time to burn more money.

    I found an ALDL plug on eBay and downloaded TSS Datamaster (demo version). I bought a ALDL to
    USB cable from John at 1320 Electronics, and he spent a good hour with me getting it working on my ancient PC laptop.Thanks John!

    I started to monitor and according to Datamaster, it turned out we were initially only triggering (3) DTC codes: 43, 84 and 97

    43 - This is an open or ground somewhere in the dual knock sensor wiring. I haven't been able to find anything that would suggest this would have any impact on the transmission, so I'm going to rule that out, unless anyone here has some knowledge to the contrary. It would seem odd to me that GM would basically cripple a car to 1st gear if the PCM lost knock sensor input.

    84 - This is the transmission 3-2 control solenoid circuit. After I cleared all the codes a few times this is the only one that never came back. Not sure what triggered it, but it’s on my radar to keep an eye out for it again.

    97 - This is an open or ground in the VSS output signal that goes to the digital speedo. The caddy has a mechanical speedo so this wire is obsolete unless we get an electrical to mechanical converter box. Based on my research this signal does not go back to the PCM, it’s purely output. We are receiving what looks to be correct MPH/ speed data to the PCM, as seen by Datamaster. So the VSS seems to be working as originally tested (we also replaced it with a brand new one to remove all doubt). I’ve read that we can add a resistor to this wire and it will remove the DTC code. If anyone has another opinion on whether or not this wire needs to be addressed in a different way, please let me know.

    Ah, here are two other notes of odd behavior. When the car is in the key-on or running position the MIL light is lit up in a solid state. Also, when the car is running, both radiator fans turn on full blast. This happens when the car is cold or hot. When I clear the DTC trans codes the fans stop for a few seconds, then they both kick back on. Very odd.

    While we were discussing my tech issues John suggested I check out TunerProRT (he sent me an .adx file, attached), and Scan9495.

    I couldn't get Scan 9495 to work at the time due to some .NET framework stuff I didn’t have installed.

    I loaded the supplied .adx into TunerProRT and unfortunately the data stream seemed all over the place. It was swinging from positive to negative numbers and wasn’t at all steady like the Datamaster data.

    Being a total amateur with all this software I tried to make a few data logs (attached). For some reason I couldn't seem to log more than a +/- 15 seconds of data using Datamaster. If any one can help with this duration issue I’d greatly appreciate it. I've burned so many free-use licenses trying to learn the software that I only have a about 10 left.

    I seemed to have better luck with the duration issue with TunerProRT, however the data seems to be junk (attached). If anyone has any insight as to what’s happening there, I’d greatly appreciate that as well.

    Once I got home I downloaded the appropriate .net stuff. I’m happy to say that Scan9495 will now fully launch, but I’m away from the car so I haven’t been able to give that a try yet.

    What I like about the 9495 software is that it looks like you can control the actuators, which will tell you if the transmission can receive a command signal. There seems to be a significant warning about not using that feature when the car is moving, so I’m a bit hesitant to try it without some wiser form of supervision. Perhaps it’d be best to track down a GM tech tool and operator?

    Given that the Datamaster data was the only stuff I could observe/ trust, here’s what I observed:

    - The PRNDL Flag value changes, the Gear Num value does not.

    - Trans Modes A & B seem to alternate states when the PRNDL value changes. I’m not sure what this is indicating. i.e. If it's a command signal going to the trans or if it's an output status from the trans.

    - 1-2 Shift Dlta T does not indicate a change at any time.

    Unfortunately, that's all I know for the moment. I'm kinda stuck.

    If anyone has any test methodologies you'd like me to try, using any of the mentioned software, I'll do my best to give it a go. Or if anyone can help me with the TunerProRT data issue that would be great as well.

    I look forward to your collective thoughts.

    Cory
    Attached Files Attached Files
    Last edited by BlackBettyLimo; 09-28-2015 at 03:16 AM. Reason: typos

  5. #5
    Fuel Injected!
    Join Date
    Sep 2015
    Posts
    59
    I realize the above is a pretty big dump of complex info, but does anyone have any thoughts?
    Thanks,
    Cory

  6. #6
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,268
    Quote Originally Posted by BlackBettyLimo View Post
    I realize the above is a pretty big dump of complex info, but does anyone have any thoughts?
    Thanks,
    Cory

    I'm wondering about the PCM flash? Is the flash $EE or $EEB?

    Can you post the .bin file that was flashed into the PCM?

    I recently worked with someone who had the wrong flash in the LT1 PCM. With the correct flash, many headaches went away.

    dave w

  7. #7
    Fuel Injected!
    Join Date
    Sep 2015
    Posts
    59
    Thanks Dave, I just emailed the guy who flashed the PCM for that info. Do you know if there's a way to interrogate the PCM to tell if it's $EE or $EEB?

  8. #8
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,268
    The PCM can be flashed either $EE or $EEB. It's a long shot the Flash is wrong, yet a likely cause of the headaches you posted.

    dave w

  9. #9
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,268
    Quote Originally Posted by dave w View Post
    I'm wondering about the PCM flash? Is the flash $EE or $EEB?

    Can you post the .bin file that was flashed into the PCM?

    I recently worked with someone who had the wrong flash in the LT1 PCM. With the correct flash, many headaches went away.

    dave w
    On second thought, lets ask for the stock unmodified .bin that was the used to start with. It might be sensitive topic with some PCM programmers, asking for a modified .bin file.

    dave w

  10. #10
    Fuel Injected!
    Join Date
    Sep 2015
    Posts
    59
    Quote Originally Posted by dave w View Post
    On second thought, lets ask for the stock unmodified .bin that was the used to start with. It might be sensitive topic with some PCM programmers, asking for a modified .bin file.
    I'm told he doesn't save the .bin files, but that he does use $EE. "What's in there is the original with the emissions and vats deleted"



  11. #11
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,268
    It was a long shot, so let's figure the flash is good.

    I don't have any new ideas, just wanted to verify the flash.

    dave w

  12. #12
    Fuel Injected!
    Join Date
    Sep 2015
    Posts
    59
    It was worth a shot, thanks for the response either way!

    The programmer says he can re-flash the PCM to remove the DTC codes (97 & 43). I'd probably want to keep the knock sensors in loop but it could be a good experiment to see if that quickly solves the issue.

    I found a post that has a break down from a service manual as follows:

    First Gear Range Only - No Upshift

    Control Valve Body (60)

    • The 1-2 Shift valve is sticking
    • The spacer plate or gaskets are mispositioned or damaged


    Case (103)
    The case to valve body face is damaged or is not flat
    Shift Solenoid Valves (366/368)

    • Stuck or damaged
    • Faulty electrical connection


    2-4 Servo Assembly (13-28)

    • The apply passage case is restricted or blocked
    • Nicks or burrs on the servo pin or on the pin bore in the case
    • Fourth servo piston is installed backwards


    2-4 Band Assembly (602)

    • The 2-4 band is worn or damaged
    • The band anchor pin is not engaged


    Since the trans has been inspected/ rebuilt, twice, I'm not sure it's mechanical at this point, but I'm not ruling anything out.

    I'm going to try and use Scan9495 tomorrow to see if I can trigger the actuators. Finger crossed.

  13. #13
    Fuel Injected!
    Join Date
    Oct 2013
    Posts
    1,022
    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.

  14. #14
    Fuel Injected!
    Join Date
    Oct 2013
    Posts
    1,022
    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.

  15. #15
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,268
    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

Similar Threads

  1. Replies: 8
    Last Post: 06-30-2015, 05:36 AM
  2. Transmission issues
    By Crash2320 in forum Gear Heads
    Replies: 4
    Last Post: 02-09-2015, 07:36 PM
  3. 2000 silverado 4x4 engine transmission mod
    By steve in forum GM EFI Systems
    Replies: 26
    Last Post: 04-21-2014, 05:50 PM
  4. transmission swap question
    By lscotty in forum GM EFI Systems
    Replies: 14
    Last Post: 10-15-2013, 01:35 PM
  5. $0D transmission segment swap?
    By EagleMark in forum GM EFI Systems
    Replies: 6
    Last Post: 10-11-2013, 07:31 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •