I was talking with Chuck Westbrook last night about putting a Power FC in my automatic car.

He seems to believe that he has seen a piggyback harness for sale by someone to run the stock ecu in tandem with the Power FC so that transmission control is retained.

Has anyone ever seen this harness or a diagram of this done?

I know about the PCS unit - but its way expensive and overkill for what I want to do. The stock ecu controls the transmission fine, I just want to remove engine control functions from it and use the Power FC. Also, running with just the Power FC isn't an option.

 

Well if you could get another harness to plug into the stock auto ecu you could give the Auto ECU all of the inputs by spilting them between the two ecu's

I think all the stock auto ecu is looking for is

Power
Ground
Park Gear Switch
1st Gear Switch - to let the cruse work
2nd Gear Switch - to let the cruse work
Speed
TPS
RPM
MAP
Engine Coolant


I think that would be all it needs to figure out what the motor is doing.

It also needs to have all the trans wires going to it.

 

I have a jspec harness I wouldn't mind butchering to make this work - and of course I have the automatic ecu.

There are some threads about this floating around. Nothing with a definite answer.

For instance, seems that at the very least, the tranny computer also requires the barometric pressure sensor input from the stock ecu: https://www.rx7club.com/forum/showth...ight=automatic

I really think someone has had success doing this.

I don't think the automatic transmission computer needs all that input Chuck, I think the transmission computer only gets information from the small plug on the stock ECU - the automatic ecu has a few more wires on that plug than the manual (or Power FC) does.

 

interesting.

 

Banzai Racing is currently developing a harness to do just that.

https://www.rx7club.com/showthread.p...highlight=auto

 

That is a cool harness, I still think i could make one for cheap

 

Now all you need is a reworked auto trans with a higher stall speed and trans brake.