My old BAC was shot so I went to the junkyard and got a new one. All of a sudden my shift up light starts working, but my car starts bucking at light throttle. SO, the question is are the BAC and shift up light connected somehow, and whats up with the bucking?

I thought BAC stood for Blood Alcohol Content? Where am I? Is it morning already?

BAC valve would have been more appropriate, besides, I'd put alchohol questions in the 'General Disscussion' section. (Unless my BAC was up there.) :P

Have you tried unplugging it to see what happens?

I don't think the BAC is even active unless it's cold... It's like a CHOKE to give the motor more air.



I don't have mine hooked up and it runs fine. I initially had removed it all together but added it for idle control.

The BAC plays a role in hot start...opens up to provide more air. It's primary function is to control the idle speed when you add a load to the engine (especially the A/C). I know for a fact that it is responsible for maintaining idle when the A/C is switched on....not positive if it compensates for head lights and other electrical loads. As for the bucking....I'd start by checking out the TPS. My car has some light surging at VERY light throttle....not sure what's causing it.



Todd



PS....The BAC does NOT act as a "choke".

To my knowledge the BAC is not connected to the shift up light.

When I unplug it my car idles fine. Somethings wierd though, because sometimes my car bucks, sometimes not. Sometimes the shiftup light works, sometimes not. and once ina while it will just die, when the ac is on. I say get a new one. As for the shift up light, i guess it doesn't really matter.

I had a problem with my car idling poorly when the A/C was on. It turned out that the transistor that controls the BAC had burned out. It's inside the ECU but it was easy to replace and only cost me like $5.00 total. My car ALWAYS idled poorly with the A/C on (stalled occasionally). Now it idles perfectly with the A/C on or off.



Todd

that sounds like us too. ac kills idle, does not idle anyway and idle screw is all way in. same way with last2 engines. all new vacuum lines and seals. when it gets hot it will barely idle maybe 600rpm`s. https://www.nopistons.com/forums/pub...#>/biggrin.png