I Have another Forum I have been working on this Buick allot for some time now.
https://www.gmforum.com/buick-172/95...r-swap-305056/

Right now I'm fine with how everything is running and showing up besides my speedometer and odometer not working. I have an engine light on and OBD1.5. So I am using TunerPro to try and pull codes. All sensor outputs are jumping to random numbers it seems, alternator shows is faulty, valve showing in open close loop, running lean and rich, and is throwing every single code on and off. But my car runs drives shifts start and everything fine. Things not working are the Traction control, cruise, speedometer, & odometer. I am being told the ECU or PCM (aka Computer) or something like that.

I replace the vehicle speed sensor connector and the sensor. This made no difference. I know that there is a sensor inside of the transmission. But since I just put this motor in and got it running the way it is I really do not want to have to drop the motor and trans out to check this one sensor. My next question is will a ABS wheel speed sensor cause my speedometer to not work. Also could it be my PCM even if all of my other tacks and sensors work and show appropriate readings?

If everything was working right BEFORE the swap, then something happened after the swap. There are 2 grounds that connect to the engine. The battery connects directly to the front side of the engine and on the back side, is a smaller ground wire that provides ground for a few sensors. Make sure that 2nd ground on the backside is connected.

Another thing. The PCM reads the VSS on the transmission and sends it to the instrument cluster. If the car is shifting/driving fine, but bad speedo/odometer, then the cluster is fault. But if the car is not shifting correctly, then the VSS is fault.

The Car seems to shift just fine not hard and will redline and shift if put to it. Everything did work before engine swap.

The two grounds on in the front I moved to the alternator bracket and one below to sensors was disconnected I found it while doing speed sensor. when I grounded it to the tranny that spit went away that I was having issues with then I gave allot of gas.

Everything is For Sure Connected under the hood. I thought there was a ground in the back by sensors but couldn't find it after the motor was in place until I disconnected allot of sensors to change the speed sensor connector.

I Still think my PCM is bad even though everything works but the small list. I also went through checking all fuses and all are good on driver side kick panel, Under the hood. Now idk how to check relays as there are a few under the hood and while I was checking out the PCM and how to remove there are also allot that I found behind the glove box. What are these relays for?

So if my PCM is bad you still think it is the Cluster? they both are going to run me about the same price.

But I tried to do another scan on the OBD and every sensor is doing like it did before still, all going from low numbers to high, and showing every single CEL code on TunerPro RT. ill be at idle and it will show engine speed anywhere from 400-7000, mph anywhere from 0-200+. it'* just making things much more complicated. I love this car and I hate to never get this figured out. I have came a long way.

Right now its hard to say what could have happened during the swap and if the scanner is truly reading correctly. I've never heard of a scanner reading like yours does. Right now, your best option is to have a dealer grab a Tech1 scanner and check for codes.

This car also sat for 4 years nefore my dad would let me take it off of his hands. At that point everything did work but the motor had a knock, died and nv started again. and every places / shops i have went to there scanners will not link up to my car. never have been able to since my gfather owner it ferrom new till the first CEL came on. he went to many dealers and not could tell him anything.

Not too many shops have the expensive $3000 GM Tech1 or Tech2 scanner like the dealerships do. I'm afraid we can't do much more until we figure out if your PCM is truly bugged out or if your scanner is bad. And we need to be able to scan to see what'* really going on.

Yeah i have heard the only scanner that work with OBD1.5 is the Tech1 or Tech2 scanners. Will any GM dealership have one of these? and the scanner I have was Brand New from Red Devil River LLC
GM OBD1 Scanner Cable Software USB to 16 Pin Aldl Direct GM Obdi | eBay
Which looked like everything i needed plus software i can even take pictures of the drivers showing up ad COM Port 1 and TunerPro set to COM1 as well as the 95 L36 3800 file.
If I did take it to a dealership what will it run for them to just scan it? $80?

I always tell members to stay away from the scanners on ebay. Many of them are cheap knock off replicas of the real thing. Many have issues with drivers, connectivity etc.

Most dealers SHOULD have them. They would be ignorant not to have one. Yes, $80 seems to be right around what they charge. Its typical shop hourly charge.

Hi - I own Red Devil River and I must have sold you the cable. I don't know what your Ebay name is so I will try to contact you here. The cable will work on 95 Buick 3800 ECMs. I build swap harnesses for people putting 3800s into Fieros. While most 3800 swaps are OBD2 Series 2 SCs, I also make them for OBD 1/OBD1.5. After I put an OBD1/1.5 swap harness together I hook up my laptop using one of my RDR cables and use TunerPro RT to scan the ECM to verify my wiring. Your ECM should be a 16183247 or equal. I do have a 1618347 ECM here on my test bench so I can send you the .ADX that I am using.

I sell the cable and TunerPro RT can be downloaded for free. Almost all the time there are problems it is with an incorrect .ADX file being used. I will however work with you to get TunerPro Rt set up so it does work for you with my cable.

Contact me at gofast@reddevilriver.com and I will help you get your cable working and help with your VSS issue. If instead you want to do it on here I am fine with that also.

Timm Bacher
Red Devil River, LLC.