Ok I just got a Haynes man. I was looking to adjust the idle on my ride (89' turboII) It's at 1500rpm right now and want it lower. The guy I got it from said it had a streetport and was adjusted this way on purpose. Anyways the manual says to adjust the idle with the turn of a screw at the BAC valve. To my shock it isn't even there!! It's got a plate where the valve would be. Wtf should I do? How do I adjust the idle now?

 

The two ways typically not strongly suggested to change the idle (but won't matter as your ecu has no affect on idle without a bac anyway) are:

1. the screw on top of the throttle body (bypass air)
2. The throttle stop screw on the front side of your throttle body opposite throttle cable connection.

Depending on the port your idle may not be stable if you change the idle. Furthermore, if you have air conditioning, fan, a stereo, or headlights these will hurt your idle without the bac.

 

Can anybody post pics to these screws?

 

aw man they got rid of the bac valve? thats one thing i would have kept if i did an emissions removal. if i were you, id look on ebay or in a junkyard and get a bac for it. your car will run so much better. but before you adjust the idle make sure you jump the initial set coupler or the computer wont read your changes. and it will be all out of whack. initial set coupler is the green connector with two terminals on it (next to the big green check connector with 4 terminals on it between the battery and drivers strut tower) all you do is get a short piece of wire 2 spade connectors on each end and jump the small connector. youll notice the car idle down to 650 rpm

 

aw man they got rid of the bac valve? thats one thing i would have kept if i did an emissions removal. if i were you, id look on ebay or in a junkyard and get a bac for it. your car will run so much better. but before you adjust the idle make sure you jump the initial set coupler or the computer wont read your changes. and it will be all out of whack. initial set coupler is the green connector with two terminals on it (next to the big green check connector with 4 terminals on it between the battery and drivers strut tower) all you do is get a short piece of wire 2 spade connectors on each end and jump the small connector. youll notice the car idle down to about 650 rpm and when your done adjusting it make to sure un-jump the connector cuase if you leave the wire in and forget about it the car will run like *** untill you take it out. hope that made sense. -matt

 

Yeah i saw where the Haynes man. said to use the jumper. What does the BAC do and what lines hook up to it?

 

^

 

The BAC adjusts the engine to the cars electrical conditions. if the lights, stereo, AC, or anything that draws current is on, the BAC stabilizes the idle.

 

if this was an n/a maybe


the PO had to have set the idle with the screw on the rear of the throttle body, pop the intercooler off and you will see an 8mm nut and screw on the throttle cam/throttle body housing near the throttle cables, it will be facing up and towards the passenger side of the vehicle. loosen the nut and back the screw out about 1/2 a turn and tighen the nut back down and reinstall the intercooler loosely, it should be close to 1000 now, readjust to preference and tighten everything down.


you will need to follow the TPS readjustment procedures to reset the TPS after the idle is where you want it. TPS adjustment can be found around the forum with the search function, note: using the key on ign. off with a voltmeter varies from car to car, some prefer 1 volt where others prefer 2 volt at full closed idle once you begin tampering with the idle screws.

 

i have a 87 turbo 2 and i was wondering why it does nothing when i turn the idle adjustment screw?