ok so i have the FAST installed in my car and all is well with the engine managment system, however the tranny management is all wrong. how do you guys with and automatic make FAST work? i left all the factory wires for the tranny in the pcm and the signal wires for the MAP, TPS and ECT in the PCM. after i plugged in the FAST harness i spliced the factory sensor wires into the FAST signal wires hoping that the FAST signal could be used as referance for the tranny. well i was wrong and now the tranny has defaulted to third.
i talked to a bunch of my GM tech buddies today about this and they told me that i might need to splice both the FAST and factory 5V ref signals together as well as the signal wires that return. that way the factory PCM can read the voltage drop and get its referance. does that sound right yo you?
the biggest question i have with the above is that if i cross thetwo 5V ref signals together whats to keep the current from flowing back into the FAST ecu? i have been told to use a diode to stop the reverse flow just in case. i am soooo confused and i have been working on this wiring non stop for 2 weeks, this is my last hurdle. the only thing i can figure to do if this does not work is to swap to a 6-speed and loose my advantage at the track but at least be able to drive to work. and i have tried the never present Mac at fasttracks for at least 3 weeks with no sign of life on the other side.
i really need help with this, if anyone with a electronically controlled tranny and FAST can tell me how you wired things up then PLEASE do.

 

i just needed the tach hooked up, the computer was not reading engine speed so i ran it off my MSD. now it won't lock up n OD. all well just another step in the endless process.