My car runs perfectly, most of the time. I've been driving it alot the last couple of weeks trying to get all those kinks out after i finally got it on the road... Every once and a while when i'm driving, usually when its not yet fully warmed up, it will act like it has a huge vacuum leak. i pull over and the car will usually stay running, bouncing up and down between 4-700rpms. If i unplug the BAC and plug it back in, it returns to a normal idle! What does that mean?

Sometimes before my car is running, if i have the key in "on" position, i can hear the BAC making a buzzing sound, which is sometimes a bit on the loud side... if that gives you any other ideas...

-jake

 

I think your BAC is sticking. Try cleaning it out with carb cleaner.

 

oh cool, thanks for the help, i've been baffled. Can anybody explain exactly what it is that the BAC does and how it works?

 

^^^ was just about to ask teh same question ^^^^

IF my car isnt warm engought yet and i drive down the block, the cars idle iwll bounce up and down , or the other alternative it will just shut off.

I dunno if its the BAC, Vac line , the missing start assist thingy (revs to 3k and gradualy comes down).

Jason NYC

 

The BAC lets the ECU inject a controlled amount of metered air past the throttle plates. It's main purpose is to compensate for loads like p/s, a/c, and electrical loads by raising idle. The other purpose is to supply part of the air used in the 17-second 3k RPM idle after cranking. The actual internal mechanism is in the training manual, but basically it's a solenoid that opens and closes an air port quickly based on a duty cycle signal from the ECU. The higher the duty cycle, the more air is let in. There's a coolant line that flows past the BAC which is supposed to keep the valve at the same temperature as the rest of the engine (not too cold, not too hot). For a bit more on the intake system:

http://howto.globalvicinity.com/gv_w...i=60&co=1&vi=1

 

oh so after a while i hear the car adjust its idle. The RPMs go up and i hear a noise in the engine bay. Always happen i guess its the BAC turning on

 

I hate to say it, but the FSM is available in the FAQ and fully explains all the systems on the engine...

 

Don't forget about the Training Manual. I find that very useful in explaining the systems.

 

yeah but sometimes its easier getting a concise explanation in laymens terms from someone who has experienced or knows about it than reading 20 pages and not fully understanding what you just read or forgetting.

Ill keep reading lol