With the key in the ON position, theres a very quick clicking that audible from the engine bay. If you try to find it with your ear, you dont hear it as much near the actual BAC on the UIM, but moreso from right around the throttle body. I never really worried about because its never caused any problems, so I just forgot about it. Recently though, I was reading through my Haltech manual and it said that the BAC was just a soleniod that clicks on and off...usually at around 10Hz.

So do you all think this could be my BAC clicking all the time? If it was, could this be the cause of my cars inability to idle when cold? And could it also be a reason why my car pulls such crappy vacuum ( Because the BAC valve is working at such a high duty cycle all the time? )?

 

double post

 

The BAC adjust the idle when the engine is under load from the A/C and power steering pump. Under the throttle body on the same side as the BAC is the 4 solenoids that are on the emissions rack. It might be one of them.

 

Well theyre definitely all getting pulled when the haltech gets put on. Do you think that could fix my poor idle/vacuum problem?

Also, I know what the BAC valve does, but Im asking IF it was bad and staying stuck open, COULD it be the source of my problem?

 

If you pull all the emissions stuff and cap the nipples with those rubber caps, then you should be able to set the idle with the haltech. Read some of the write ups and talk to some of the members here about removing that emissions stuff. There will be a few vaccuum lines that you will need to keep.

If the BAC got stuck open, then I think that would mean it would be constantly energized. Therefore, the problem would lie in the source of the power constantly being applied to it.

 

Im not asking why its staying energized ( if indeed it is )...

All Im asking is the simple question If my BAC valve is stuck open, could it cause me to not idle when cold and pull very little vacuum when hot?