Downshifting problem
07-31-2006, 02:30 PM
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Staging Lane
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Downshifting problem I have a 1990 Miata with a an LS6 engine in it (total weight 2640 lbs). The rear gear ratio is 3.58. I also have a stall converter installed (TCI Street Fighter).
Starting with the 2002 Camaro PCM code, I swapped in the 2004 Corvette Z06 PCI fuel, air, and spark tables, etc. So it is running as an LS6 now. Major difference in power.
I immediately noticed a massive power difference. The car runs very well. Unfortunately, I seem to have developed a problem when under hard acceleration.
If I am driving at say 45 or 50 miles per hour and I hit the accelerator where the engine needs to down shift, there is a period of time when the transmission is not engaged. The engine races. I take my foot off the gas and it reengages. I can then take off again.
This didn't happen with the old 1999 Camaro PCM code. The engine is making a LOT MORE HP.
From a stop, it seems to run very well, but from a roll that requires a downshift, I am running into this problem.
Car too light? Torque converter causing too much increase in rpm? Real problem in the transmission?
I just rebuilt this tranny and it ran fine with the 1999 PCM but who knows?
Sam
Starting with the 2002 Camaro PCM code, I swapped in the 2004 Corvette Z06 PCI fuel, air, and spark tables, etc. So it is running as an LS6 now. Major difference in power.
I immediately noticed a massive power difference. The car runs very well. Unfortunately, I seem to have developed a problem when under hard acceleration.
If I am driving at say 45 or 50 miles per hour and I hit the accelerator where the engine needs to down shift, there is a period of time when the transmission is not engaged. The engine races. I take my foot off the gas and it reengages. I can then take off again.
This didn't happen with the old 1999 Camaro PCM code. The engine is making a LOT MORE HP.
From a stop, it seems to run very well, but from a roll that requires a downshift, I am running into this problem.
Car too light? Torque converter causing too much increase in rpm? Real problem in the transmission?
I just rebuilt this tranny and it ran fine with the 1999 PCM but who knows?
Sam
07-31-2006, 03:00 PM
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If your running a 4L60E out of a '99, you should run the trans tables from a '99 as well. The settings between '02 and '99 are different and respond differently as far as I know. Try setting the tables back to '99 specs and see if it helps. It's a lot of copying/pasting...just don't forget to save the tune seperately.