i was putting on a cone filter on my car today (yes it is finaly no longer stock) and i decided to check my bac, so i started the car and let it warm up, well it could never realy hold an idle good, it always did that little auto reving thing (thats what i call it), anyway i turned on all my ****, lights, a/c, ect..... well i un plug the bac and of course the engine died, took everything off and started the car agian (bac still unplugged) and walla idle is steady at 1k, so does this mean the bac is dirty, clogged? i would have searched but if u ever searched "idle r bac " u would know y i didn't


-Shawn

 

my car does teh same auto rev too I hate it let me know if you figure out what it is I already adjusted teh tps to death and nothing and I see no vac leaks on the top of motor. the odd thing is I can chock down the idle with bac but will auto rev if I dont knock the idle down with clutch.

 

oh thanks for reminding me i also have no vac. leaks, also it dosen't idle so bad with the a/c on but still does it, and for some odd reason after driving it hard it will idle prefect for about 5 min and then start auto reving agian

-Shawn

 

http://www.1300cc.com has a nice writeup about cleaning the BAC. It's not a hard job - I'd recommend that you go ahead and do it. With the exception of the hunting idle, the behavior you've described is pretty much normal.

While you're in there, set your TPS. According to the FSM, the S5 ECU should automatically adjust to whatever values it sees, but the system doesn't work very well. Using a DMM, set the resistance across the narrow range TPS to 1.0 ohm, and check that there are no dropouts or odd fluctuations across its open-close range.

Once you get it settled down, see where it sits. If it's off, check back with us.

Brandon

 

I just posted a How- To, on cleaning the Bac Valve. Let me try finding It. Infact there Is nothing to It...

 

WELL HOW ABOUT THE S4? N E THING DIFFERENT IN THE PROCESS OF CLEANING IT? hey silverrotor ... u find that write up yet?

 

right here. Keep In mind It's very simple. https://www.rx7club.com/forum/showth...hreadid=137147

 

sounds easy enough i'll give it a shot when i get some more time on my hands, thanks i'll let you know if it solves the problem

-Shawn