Alright so I have a BAC problem I believe. After doing the TB mod, replacing some fuel lines, replacing my PD, porting the intake manifolds, etc, my car wouldn't start.

Turned out it was super flooded and I finally got it to start but it was smoking and I had to hold the throttle down to keep it running.

Eventually it was warmed up and had stopped smoking and was able to hold its idle, but it was idling at 500-550 and acting like it wanted to die.

I checked everything the FSM says to adjust idle (variable resistor, TPS, idle adjustment on top of the TB) and that didnt change anything. Then I checked the BAC by cleaning it etc. like the FSM says.

I also took the connector for the BAC off to check for resistance on the BAC terminal, and it was within the specs that the FSM said. The FSM also said to hook up a 12v power and a ground to the BAC terminal (which I did) to check that it clicks, and it does.

So the BAC was all in working order, I turn the car back on and it still idled at 500-550. It also does not want to hold an idle for the first few minutes after I turn the car on, so I have to hold the throttle a little to keep it running, but eventually it will stay on without holding the throttle.

Then, as a last test, I took the plug off the BAC with the car on and hooked the 12v and ground back up to the terminal to see if it would do anything while the car is on. YEP!! It did... it caused the idle rpms to go up and fluctuate between 1500 and 1750.

Any ideas on why it's doing this or how to fix the BAC?

Also... the Pressure Regulator Solenoid valve (orange) and the Switching Solenoid valve (gray) are broken, but I dont think these would affect the BAC, would they?

 

bump

 

After doing the TB mod youre idle is going to be pretty screwed up until you readjust it. I suggest trying RETed's writeup here http://fc3spro.com/TECH/HOWTO/TPS/tps.html

 

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

 

Yes I know, already did that, everything's been adjusted, my problem is the BAC is screwed up.

 

Read above, plus thats for a TII, I'm N/A

 

In the article, far down in the article, it tells/shows how you can find out if the signal from the ECU to the bac is good or bad.

Although its really not that hard to tell if the thing is getting a signal or not. IF the idle is below 750, or even better if it's lower and you remoe the bac's elec plug while idling and the idle speed does not change a whit......then the transistor in the ECU is fried OR one of the two sockets in the BAC plug is pushed back and not locked in.

Before I owned a turbo and I had just a 87non turbo, used that article to fix my ECU by replacing the transistor in the ECU. With the new transistor the thing works now like a charm.

So that part of the article is applicable to non turbo cars also. Been there and done that. Radio Shack had the transistor.

 

Yah I've done the test where you pull out the plug while the car is running, and my idle didnt change. So I guess its crapped out somewhere? Time to block it off? heh

 

No/Yes/depends. If you are not too hot on soldering maybe you have a friend that can unsolder the old transistor and install the new one. The cost was less than two bucks for the transistor. I have no skills at soldering and did it. Blind luck??? Got me. It DID fix the bac though.

I don't see the value in blocking the bac off if you don't replace the transistor. It does no harm sitting there and cost nothing to leave it there.