98Z28CobraKiller

iTrader: (17)

I have a 98 PCM car and a 99 PCM car that I am trying to figure out how to tell the computer that the car is in reverse. Both cars have autos (one is a TH350 and the other is a Glide) swapped into them and have no electronics hooked to them. I am trying to setup a 2 step by using HPTuners to set a low rev limiter in reverse. Once the tbrake is engaged, I would like to signal the PCM that the car is in reverse and use the rpm vs gear table to set the rev limiter to say 3500 RPM for the launch. Once you release the tbrake, the car should go back to the normal rev limiter.

Thanks in advance.

Search has not yielded anything of value.

poolshark021

iTrader: (8)

The 4L60E's have a pressure switch bolted on the valve body that send a ground signal to the pcm on 3 different wires depending on what gear it is in. From the looks of it, you want to ground out the pink wire (terminal N on the stock trans connector) to signal that it is in reverse.

98Z28CobraKiller

iTrader: (17)

Will the wire be present in a car that had a T56 in it from the factory? Just making sure before I rack my brain looking for it. I imagine that there must be a pin in the PCM regardless.

poolshark021

iTrader: (8)

Well you could make a wire for the pcm pin, but you need to flash an A4 file to the pcm in order for it to work. On the 98 pcm it is C1 (red) pin 25, on the 99 pcm it is C2 (red) pin 63.