TCC at max duty cycle at anything over 2mph - can't find why
I've got a 2000 Trans Am LS1/auto that is driving me nuts. I have a 3600rpm stall converter in it but you couldn't tell because at any speed over 2mph the converter is locked up. Max duty cycle is at 96% and driving down the road it is at 96% the whole time, except for WOT upshifts when it dials it back for just a moment and then it's fully applied again. Even with applying the brakes, the converter stays locked up until you're down to 2mph and then it snaps out to 0% duty cycle, which REALLY has me confused as I've never experienced a trans that would stay locked up when on the brakes before.
The problem is I don't see anywhere in the tune where it would be commanding this. I could change the TCC lockup tables... which admittedly aren't too far off from where I'd want them already... but nothing is calling out to me "lock up as soon as you're rolling at stay locked up always!". So I think I'd be wasting my time until I find out why the computer is commanding full lockup.
Is there anything I could be missing, or is there a TCC engagement map somewhere other than in the Transmission's TCC tab?
Looking at you file it does not seem to command TCC lockup until 3rd gear and 60 MPH plus. To be completely honest you should be having some serious driveability issues (wanting to stall the engine or bucking) with the vehicle if the TCC is locking up at 2 MPH, even with speeds of 5-10 MPH. You should log the vehicle and make sure you are monitoring all of the TCC PIDs (Channels), especially TCC Mode to see if the TCC is being activated. Post up the .hpl scanner log file if you want any of us to review it, may be we see something you don't.
What 3600 stall TC are you using? Manufacture, what design (multi disk, single disk)? Usually aftermarket TCCs are designed to be 100% engaged when the TCC is activated (100% Duty Cycle in other words no Pulse Wide Modulation). To accomplish no PWM you need to set the Transmission>Auto TCC>TCC Duty Cycle> Maximum = 100 (all cells) and Transmission>Auto TCC>TCC Duty Cycle> Minimum = 98 (all cells).
Last I would suggest you read this thread below and download the Bluecat Transmission software. Helps automate the hole transmission tuning process and works great.
I logged with an OTC instead of the VCM and found up to +1600 and -900rpm "slip" even with the TCC "engaged" in the lower gears, so I am thinking that it's data error. The reason why it felt like it wasn't on the converter was due to some other unrelated faults.
It's a triple disk converter, I'll get in contact with the manufacturer to see if they don't advise converter PWM.
I'm definitely going to look into the Bluecat software for adjusting shiftpoints, another problem is the trans shifts up to 3rd gear almost immediately and then doesn't want to kick down...
Reply With Quote