Problems with Compushift controller

[ss dave]

Just finished up the project, a LS7 with a 4l60e. Drove the car two days ago but the tranny controller sucks. Shifts too early and won't hold a gear long enough for even a decent burn-out. I'm going to call the Compushift guys next week when I have more time, but any thoughts on what could be wrong. Got a low signal and when I talked with them they stated that may be normal????

[Steve Chryssos]

Low battery voltage for one. That is a frequent culprit. TPS calibration is another biggie. If your car has throttle by wire, be sure to specify that when you talk to them. Mike Hoy over at Compushift will do backflips to set you straight. He's that kind of guy. He has a full service transmission shop as well, so he can help diagnose every aspect of the system. In case it is the TPS, don't drive it. And for sure no burnouts until it is right.

[ss dave]

Thanks Steve, I was hoping you would comment. I've talked with Mike in the past and found him very willing to help. By the way, the fender braces got alot of attention in last weeks car show.

[Steve Chryssos]

Cool, thanks for the business. So how is your alternator? And are you running throttle by wire? I'm more concerned about the TPS since your symptoms make it sound like the TCU thinks you are at or close to idle all the time. With the engine off/key on check the TPS readings on the TCU.

Oh, and until you get it right perform ALL in gear testing with the rear wheels on jackstands--two inches off the ground and front wheels chocked. Remove the load from the drivetrain until you know that the system is close. A big, smoky, TV Tommy Ivo burnout is not an accepted diagnostic protocol.

[ss dave]

Alternator is fine, yes its throttle by wire. I'm itchin' for a big fat smoky burnout, but I get your point. I'm sitting down with my builder on Monday and we'll talk with Mike. Thanks.

[Steve Chryssos]

........yes its throttle by wire......

Yuk! Bollocks! Okay, here's the schematic for TBW. Note that there are two sets of redundant wires and that they measure in opposite directions--one is 0-100%, the other is 100-0%. Wires are Dk Green (485), Purple (486) and dk Blue 417. But measure with a multi meter to confirm 0-100%--If you can't or don't want to make the TPS splice work, you can get a remote TPS kit that is cable operated and bypass the TBW altogether. Mount a ballstud to the throttle lever and attach a cable to the ball stud with a separate TPS on the other end of the cable.

[ss dave]

Thank you, thank you.