Guys,

My '87 TII will not idle with the A/C turned on and unplugging the BAC makes absolutely no difference in the idle (A/C on or off), it's safe to say the BAC is doing absolutely nothing. I tried another BAC (both of them had been cleaned and tested per the FSM) and got no change in anything. Last year my BAC connector broke, slipped down and shorted out on the manifold....this blew a fuse in the main box in the engine compartment (don't recall which one). It happened at least twice before I figured out what it was. I figure either the wiring is bad to the BAC now OR the ECU transistors burned out per the FC3S.org write-up. So...my question....anyway to test this without purchasing another ECU. I do get voltage betwee the two contacts on the BAC plug...does that mean anything?

Thanks in advance for the help.

Todd

 

The black/white wire should have 12v approx. If you connect the bac, engine running you should be able to (not a preferred practice) stick a needle into the LG colored wire and see approx 7volts or there abouts if you touch your meter to the needle and the other lead to ground.

I've replace one of these transistors in a N332 ECU. The instructions at http://www.teamfc3s.org/info/articles/idle.html are clear cut and the transistor was less than five bucks. If I can do it, anybody can.

Can't really say if the voltage on the meter with the two leads connected to each socket on the bac valve really means anything. I'm limited. I do see approx 12v doing this with the connector off the bac. Better to connect the plug and do the needle invasion as described above.

 

Todd I have a 90 gxl na, it has the same problem but its an automatic. Right now its at the shop . New ehaust racing beat and greddy and an intake system The fc3 write up looks simple but I havent tried it yet. Actually I havent even drove the car yet,It sat for a while. Its now running and I should have next week. I havent been much help but had to reply when I saw you were from roanoke, Im 2 hours south east. GOOD LUCK

 

Guys,

I saw that write up but my soldering skills are pretty basic and the thought of disassembling the ECU makes me sick! Anyway....do you think it's likely the transistor has burned out given the symptoms I described? ZOOOOOOmmmmmm....you should come up sometime and let me check out your car. I've been thinking about a RB exhaust and I'd love to hear it first hand.

Todd

 

Hailers,

Where / What transistor did you purchase?

Todd

 

Damn....I forgot to ask!

Hailers...did the transistor fix the problem with the BAC?

Todd

 

The T801 that is described in the http://www.teamfc3s.org/info/articles/idle.html its mentioned near the bottom of the article. The part is a TIP120 (NPN Darlington . Buy some soldering wick. Its just some copper braid that soaks up the solder as you heat the old soldering pins. Sucks the old solder away so you can pull the old transistor out without making a mess or overheating things. The board has the T801 written on the board next to it.

Yes, it fixed the non working bac. That bac did nothing until I put a new transistor in. What have you got to lose. A used n332 cost maybe fifty bucks.

 

Hailers,

Thanks so much for your suggestion. I replaced the transistor in the ECU and now my car idles fine with the A/C and all other accesories turned on. It's so nice not to have to turn the A/C off everytime I have to stop! It wasn't too bad eventhough I can't solder worth a damn. The radio shack part number is 276-2068 for an NPN TIP 120 transistor. It cost me all of $1.95 + tax. Again...thanks a bunch for your help...wouldn't have done it without you. I wish I had taken pics. to help others with this.

Todd