I have had my tuner for quite some time now without the complete success of it working on my car. I own a 2000 Buick Regal GS with the modifications in my signature below. I have a Dynotech Stage II Transmission with the 3.29 gear ratio. My stock PCM was tuned with a DHP tuner which damaged the OS ID #. So I purchased another 2000 Buick Regal GS PCM with the correct OS ID # and VIN # as my car was originally stock. I loaded the replacement PCM into my car and copied that bin file to my desktop. I then opened up my stock tuned pcm bin and manually copied over the number differences from one PCM to another. Most likely my car would not even run on a stock PCM anymore so this had to be done. Also a stock Regal GS PCM has a 2.93 gear ratio instead of 3.29 like my transmission has. After started the car for the first time with the PCM it ran perfect without any check engine lights. However as soon as I put it into gear to move I noticed the transmission was whining and when the car would shift into any gear it would slam into gear pretty hard. Shortly after returning home the check engine light came on and it was
[PCM] P0730 - Incorrect Gear Ratio (Pending) (Old) (History) (Current) (Immature).
I don’t understand why it would say it was the wrong gear ratio because I copied over the correct number to run 3.29 in the PCM. These were also the same numbers that were in my original PCM that shifts perfectly. When I was scanning the calculated gear ratio it was 3.984 at idle then would go down to 1.750 while I was driving. Is that correct? I haven't scanned the car yet with that field with the working PCM. I will have to do that tomorrow. I found out that because the gear ratio was somehow incorrect it was causing the transmission to go into “Limp Mode” commanding max pressure (the trans whine) which resulted in extremely hard shifts. I installed my original pcm back into my car and it drove like nothing ever happened. So for some reason the data for the 3.29 gear ratio that I am putting into this stock replacement PCM is not working correctly. Keep in mind EVERYTHING else works perfectly except the trans shifting. The car even shifts at the same time like before. Just much much harder then before. Below I have posted pictures of the Speedometer pages in my working PCM bin, the non working PCM bin, and also a stock regal GS bin.
Picture of my working Speedometer settings in DHP tuned PCM (3.29 ratio)
Picture of my non working speedometer settings in replacement PCM (3.29 ratio)
Picture of speedometer settings in a stock Regal GS PCM (2.93 ratio)
Now my car stock has 225/60/R16 tires. When I check out the diameter size for 225/60/R16 it comes to 26.6. However in those pictures you can see it says 25.82. However that is how the settings are in a stock bin file on the tire size 225/60/R16. I thought it was really odd how the numbers are 25.82? If I do put in the tire size number 25.82 and gear ratio 3.92 it changes the Trans Revolutions as you can see in the picture below. What does that mean?
Picture of Speedometer Saved in new PCM with changes
I have been told to go to the GM dealer to get my working PCM flashed back to stock. So I made the calls and have gone to a few places and because of the mods and changes I have done to my PCM half of the GM dealers don't even want to touch it (liability). Or they want to charge me a ridiculous amount to look at it and this may not even correct the problem. If they flash that working DHP tuned PCM and I run into the same transmission gear ratio problems after its been flashed I will be stuck without a driving car. I Just don't understand why the same settings in my working PCM work fine however copied over to another PCM it will not work? There has to be some type of speedometer gear ratio glitch? I have seen a few other posts about people having gear ratio problems however I can't seem to find a solution. Do I need to make more changes to the speedometer page besides changing the Drive Sprocket Ratio from 1.121 to 1.000? I really hope I can have this problem fixed before winter is over. The reason I been trying to tune this car is so I can fix my cooling fans which come on way too early for the winter.
I hope someone can shed some light on this situation? I don't want to keep messing around and possibly causing damage to my Dynotech Transmission.
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