BAD IDLE and DIE w/ AC ON..
 

I know a lot of ppl say troubleshoot the TPS and BAC Valve but did anyone ever figure out "THE ACTUAL CAUSE"? Please share your info... I like to know...

THANX,

Honestly, I fixed this problem before by doing the TPS adjustment. Have you tried this?

With the BAC valve, it could be one of several things. In order of likelyhood:

- Dirty/clogged
- Not plugged in
- Broken wire
- Fried transistor in ECU (go here)

The actual cause is a malfunctioning BAC or TPS.

Wadda ya mean did anybody find out the cause????? Heck yes. I think with Six Rotors it was a socket on the plug of the bac pushed back not making contact. I've had that same thing happen to me. I also had a spare ECU for the turbo that had the bad transistor for the bac, so that the bac was non functional. See the article by PaulStoakes (without a doubt one of my heros) at http://www.teamfc3s.org/info/articles/idle.html

And if its not one of those, I'd suspect the idle without the initial set coupler inserted, is not at 750, so that when the coupler is removed, the bac is having to take up the slack. Then when a load like a/c is put on, the bac can't carry the extra load.

Just look up Akageals name and a thread by him. Not only did the repaired transistor fix his car dying with the a/c on but it also solved a hot start problem he was having .

Actually READ http://www.teamfc3s.org/info/articles/idle.html

I have the same problem, so I bought a used(in working order)TPS to trouble shoot. My idle would drop to a minimum..just enough to stay running, when warm. I installed the TPS and now my idle stays at 750 when warm, but when I start cold..RPM's start high like usual, but then comes down and shuts off, and when I step on the brakes while warm the RPM will drop to minimum again unless I release brakes. I already cleaned out my BAC valve(except I did'nt put power to it during cleaning to open it). I guess it would be safe to say that I now need to purchase a BAC valve. Anyone know of a place to get a good price on one?

I doubt its the bac. Put 12v on it and see if it opens and shuts when power is applied and released. Go read the article http://www.teamfc3s.org/info/articles/idle.html and the part of it about the bac. Look at the plug on the bac. Is one of the two sockets in the plug pushed back? And if you can't do what is written in the article at that url, try something unique. If you have a spare fuel injector, start the car and let it idle. Take the plug off the bac and put the plug to the spare fuel injector. It should pulsate if the ECU signal is getting there.Works on a 87 model anyway. READ THE ARTICLE AND UNDERSTAND IT. PLEASE.

My problem was a bad throttle body. It is not operating properly consistently. I currently have the idle set to 1000 RPM's until I get my throttle body replaced.