1985 Caddy Limo - Engine swap with transmission issues

[BlackBettyLimo]

I have to applaud your perseverance in this.

Haha, I'm so deep in. The only way out, is through.

[Terminal_Crazy]

Sounds like you're getting there. One thing to note is do not ground the PCM. Make sure your bracket is insulated or plastic.

Out of curiosity.. why ? noise?Presumably the PCM case is connected to a ground connection through the plug connectors.Mitch

[BlackBettyLimo]

Today was better than the last two combined. I uploaded the final tweaked bin file (EGR scalar corrected, and oil life/ level turned off) and the limo is running pretty smoothly now, and I'm not seeing any DTC codes.

We were screwing around with the PNP wire and as mentioned by a few of you guys in prior posts, it mainly has to do with the IAC circuit. Without the PNP grounded the idle RMP hunts from 630 to 670, and IAC values are 0. When you ground PNP the IAC value slowly increases to around 19-21 and the idle picks up to 700-715. It hunts a bit less with PNP grounded. Unfortunately my steering column only has a mechanical neutral safety switch, so there's no signal for me to hijack. My 4L60E does not have an external neutral switch as later years added, however the casing does have the mounting bosses for it. So perhaps i could buy a neutral switch and wire up a work around. They are only $40. If anyone has any experience/ feedback if that's a wild goose chase please let me know.

We were feeling pretty brave and decided to go on a road test and fill up the tank. Thankfully she ran smoothly and without incident. All shifts felt clean and the engine sounded happy. I'll probably run this bin for the time being. I was comparing transmission shift values with the hearse bin and they have higher thresholds, so it may be worth giving that a go and see how the ride characteristics change for driver and passenger. I think slower/ longer responses to driver input might be better if we've got drinks in hand in the back.

We got back to garage with some fresh optimism and started to dive in to the Caddy's ECM connectors. We found most of the dashboard indicators and were able to pair them with the LT1's PCM. Service Engine Soon (MIL), Service Now Stop Engine Temp (Cylinder temp sensor), Stop Engine Oil Pressure (added a sensor, operates outside of PCM)

Remaining punch list items:

I just realized the TCC Temp Switch is not hooked up, that got buried on a punch list somewhere. How critical is this?

PNP wire, as discussed. May just leave circuit open for now.

I've been running without the "home base" air intake plenum. Any idea if the the car run louder or softer if I put it back on? There isn't room for the other resonating baffle after the air box.

Need to hook up the No Charge Indicator light on dash, although I'm running a single wire alternator now. Not sure how to attack that yet.

Getting closer!

[BlackBettyLimo]

Maybe a variation for this for the PNP circuit. i've seen some threads referencing a diode, but have yet to understand the need or application.


Attachment 9828

[lionelhutz]

Not grounding the PCM is to eliminate ground loops. The PCM is grounded through the harness connectors and typically the wires go to the engine where it needs to be grounded. A number of people have fried their PCM by grounding it to the body and then having it complete the ground connection from engine to body. The GM holders are always plastic for good reasons.

I think there are different idle rpm target tables for park and for in gear. I'd have to fire-up my tablet to take a look and confirm. If you find them, make the lower table the same as the higher rpm table and then it should idle the same regardless of the P/N wire connection. I never bothered with the switch. Mine runs pretty good without it and I just can't be bothering making something up to wire it. I haven't heard of any good reason it needs it. Your relay idea looks good but then it just adds another possible component that cause a no-start when it fails.

I'm not sure what TCC temp switch you're looking at. There is a temperature sensor inside the transmission but it's wiring is part of the harness to the transmission connector and you should have got it if you kept the transmission harness.

I don't know what a "home base" air intake is.

The 1-wire alternator should still have the light terminal you can connect a charging light to.

[BlackBettyLimo]

Not grounding the PCM is to eliminate ground loops. The PCM is grounded through the harness connectors and typically the wires go to the engine where it needs to be grounded. A number of people have fried their PCM by grounding it to the body and then having it complete the ground connection from engine to body. The GM holders are always plastic for good reasons.

I think there are different idle rpm target tables for park and for in gear. I'd have to fire-up my tablet to take a look and confirm. If you find them, make the lower table the same as the higher rpm table and then it should idle the same regardless of the P/N wire connection. I never bothered with the switch. Mine runs pretty good without it and I just can't be bothering making something up to wire it. I haven't heard of any good reason it needs it. Your relay idea looks good but then it just adds another possible component that cause a no-start when it fails.

I'm not sure what TCC temp switch you're looking at. There is a temperature sensor inside the transmission but it's wiring is part of the harness to the transmission connector and you should have got it if you kept the transmission harness.

I don't know what a "home base" air intake is.

The 1-wire alternator should still have the light terminal you can connect a charging light to.

Haha based on a few LT1 forums, "home base" (aka "home plate") was the way people were describing the top air cleaner which looks like a home plate from a baseball diamond. I wasn't sure if it acted more like a sound baffle (eliminating drone at certain frequencies?) or just tuned the general tone of the engine.

hmm, I thought I had stubbed a wire out that was labeled TCC temp, that was outside of the Trans plug. I'll double check.

I'll also check out the Alt and see where the light terminal might be hiding.

Thanks for the insight on the PCM loop grounding. Right now the PCM is mounted in an aluminum mount, however, that is affixed to the top side of the plastic wheel well of the Caddy so it's actually 100% insulated from ground loops. Maybe I'll rover the thing in electric tape just to be safe.

I'll dig around and look for the PNP table your referring to. I think my brain is finally beginning to understand TunerPro a bit. Emphasis on "a bit".

I really appreciate the time you've taken to help throughout this project! Thank you!

[BlackBettyLimo]

I can't believe it's been six years since I started this LT1 swap thread! I just re-read the entire thing a few days ago and honestly it was like reading a foreign language, I had completely forgotten everything. I just brought myself back up on to speed on $EE, BIN, XDF, ADX, Datalogging, Scan1995, WinFlash, TunerPro. This thread was so helpful, both then and now, so thanks again for taking the time to help with this project. During my refresher course I found the latest EEX definition file and the latest V5 of TunerPro, so great to see the development continue! I'll be sure to make some donations shortly.

Overall, the limo has been running well. Last year we took the plunge and got some new paint/ carpet/ interior, and I finally got the AC working just in time for winter. I'll need to update the BIN for that at some point, I think we turned all of the AC related diagnostic stuff off.

Punch list wise, I think I may need to install a power steering pressure switch (doesn't exist on original Cadillac system) to let the ECU adjust RMP when under load. The car will die every now and then during a tight low-speed cornering event. I also need to get the OEM Air Pump back on, get a VSS to mechanical cable converter box installed so the dash speedo can work again, replacing some leaky trans lines, and sort out some door lock issues.

Other than that she's a runner!

Here's some updated pics:

IMG_3096.jpg

IMG_0163.jpg

IMG_0159.jpg

[BlackBettyLimo]

Oh btw, during my deep dive I came across a EE Speedo Calculator.xls from EagleMark. Now I might be getting a bit out of my league here, but I noticed that the formula for Speed Scalar - Divisor in the .xls ((PPM + Speedo Scalar-Base)/4000) differs from what the rollover "tool tip" in Tuner Pro says (4000/ (PPM + Speedo Scalar-Base)). Just wondering if the tool tip in Tuner Pro is a typo/ flipped?

There is also a very small discrepancy in the labeling between TP and the xls, which for a slow-on-the-draw guy like me found a bit confusing. The xls refers to "Scan Tool Scalar" and TunerPro calls it "Speedometer Scalar - Scan Tool". Seems like it should be obvious, but I'm thick. So, I've re-formatted it a bit for newbies like me and also added (hopefully accurately) a Tire Size to Revolution Per Mile calculation in there.

Here's the formula I used: ((Tire Section x Aspect Ratio (in %) x 2) / 25.4 (mm --> in conversion #) + Wheel Size (R)) x 3.1416 (Pi) = Tire Circum in inches/ 12 = Ft/ 5280 = Revs per Mile

Does anyone know how to upload an.xls file? I only see options for pics and video

Here's a temporary Dropbox link if you want to check it out: https://www.dropbox.com/scl/fi/moe8p...fdoxbmbba02q30

Am I correct in understanding that the three Speedometer Scalars (Base, Divisor, Scalar Tool) are only values you need to change when dealing with Rear End Ratio and Tires Size?

[1project2many]

Nice to see you're still around.

Overall, the limo has been running well. Last year we took the plunge and got some new paint/ carpet/ interior, and I finally got the AC working just in time for winter.

The limo looks great. The seats look very comfortable.

Just wondering if the tool tip in Tuner Pro is a typo/ flipped?

I *believe" the rollover tip is correct. Open the XDF and look at the formula to confirm.

((Tire Section x Aspect Ratio (in %) x 2) / 25.4 (mm --> in conversion #) + Wheel Size (R)) x 3.1416 (Pi) = Tire Circum in inches/ 12 = Ft/ 5280 = Revs per Mile

This formula calculates feet/rev/mile or miles travelled per rev.
29.5" dia # pi = 92.676905 in / 12 / 5280 = 0.00146270.

You need to invert the result to get rev/mile:
1/.00146270 = 683.66

The challenge with using completely calculated values is that the unloaded tire circumference does not match the loaded (or rolling) tire circumference. For the same 92.5" circumference tire the actual rolling circumference requires 708 revs/mile.
https://www.goodyear.com/en-US/tires...-a/sizes-specs

Am I correct in understanding that the three Speedometer Scalars (Base, Divisor, Scalar Tool) are only values you need to change when dealing with Rear End Ratio and Tires Size?

That's all I change.

Does anyone know how to upload an.xls file? I only see options for pics and video

Hmm... what are you seeing? Feel free to contact me off-list to keep this thread clean.

From the "Attachments" section of a post reply page:
Valid file extensions: adl ads adx bin bmp cal ctz doc ds ecu efi gif hpt jpe jpeg jpg ods pdf png psd src tun txt uni wav xdf xdl xls zip

[BlackBettyLimo]

I *believe" the rollover tip is correct. Open the XDF and look at the formula to confirm..

Screenshot shows 4000/ X vs X/4000
Image 12-6-21 at 7.19 PM.jpg

The challenge with using completely calculated values is that the unloaded tire circumference does not match the loaded (or rolling) tire circumference. For the same 92.5" circumference tire the actual rolling circumference requires 708 revs/mile.
https://www.goodyear.com/en-US/tires...-a/sizes-specs.

Ohhh I hadn't thought about load as an influence, thanks for the clarification.

That's all I change.

Great, thanks

From the "Attachments" section of a post reply page:
Valid file extensions: adl ads adx bin bmp cal ctz doc ds ecu efi gif hpt jpe jpeg jpg ods pdf png psd src tun txt uni wav xdf xdl xls zip

-forehead smack- I was using Quick Reply instead of Go Advanced. I told you I forgot everything...

[BlackBettyLimo]

Formula wise it seems like we are coming to the same conclusion whether it’s by Tire Size or Diameter the results basically the same, despite the fraction rounding difference. I updated the .xls to V3 which has both calculations. Attached.

I used your Goodyear link and ran a few of their tires though both calculators, not only make sure they were giving the same calculated results, but to compare and contrast Goodyear’s listed rev per mile number vs our calculated one.

Here are value differences between the published Goodyear rev per mile value, minus the calculated one (always a lower number):

245/75R16 = +24 (i.e add this number to the calculated value to meet the manufacture's published rev per mile)
225/70R15 = +26
265/60R18 = +21
275/60R20 = +23
275/55R20 = +23

It looks like the average adjustment needed to be applied to the calculated value is +/- 23 rev per mile, so I added a "Rev per Mile Adjustment Value" cell to the spreadsheet and tested everything using a Goodyear 275/65/R18 (32.1 Dia, Revs Per Miles = 651).

The calculated result is now 651.x, within 1 revolution per mile rounding error.

Not too terrible?

[steveo]

one problem with the speedo correction is that, if you're using an electronic transmission, a lot of transmission shift points are vehicle speed based
since the vehicle speed is taken from the trans it will shift perfectly until you correct the speedo, then it'll shift in odd places
so you have to scale all those too

[BlackBettyLimo]

one problem with the speedo correction is that, if you're using an electronic transmission, a lot of transmission shift points are vehicle speed based
since the vehicle speed is taken from the trans it will shift perfectly until you correct the speedo, then it'll shift in odd places
so you have to scale all those too

Hey Steveo,

Thanks for the quick reply

The limo is shifting pretty well overall, sometimes there's an abrupt 1-2 shift (depending on rate of accelerator input), but usually it's pretty darn smooth. I'll have to interrogate the ECU and pull the existing BIN to see if there were any mods made. We might have used a BIN for a hearse (EE_16200281 1994 D Hearse Auto 2.93.bin) as our base since that felt like they could be similar rolling weights. I can't remember if one off you fellas massaged that data or not when you were helping me ago long ago, but as I'm typing this... obviously that BIN is calibrated for a 2.93 rear end vs the 3.42 we have, so it would take sense if there was an adjustment.

Out of curiosity are there multiple scalars to adjust? I'll dig around a bit tonight and take a look at TunerPro. I should be getting out to the limo in a few days to grab the current BIN.

[steveo]

i think anything in the transmission tables that has a value in mph is worth taking a peek at