I understand disagnosing and solving an idle problem via internet is pretty much near impossible. But I've already been to a pretty reputable shop in my area (Rick's Rotaries Pleasenton, CA) and they haven't had any luck. I bought my 87' with no emmission parts waht so ever (block off plates), no bac, or aws. So whenever I had to start the car, on coldstarts, it would not hold an idle. I would have to hold the throttle down until it would its fully warm to have it hold an idle. I brought it to a shop and this is what they said they did; "Ok, so we found that the air/fuel mixture at idle was very lean. We adjusted the airflow meter to the right mixture and the car runs good at idle now. The screw had to be turned all the way closed to get the idle smooth.* There may be some minor vacuum leaks or restricted fuel injectors causing the need to run a richer than normal idle mixure." So long story short, they got the car to idle on its on during cold starts. But after awhile, after installing a sound system, it stopped and went back to how it was again. And upon installing my sound system, on initial hook up, I heard a "pop" from the engine bay, but couldn't figure out what it is cause everything runs fine. Everything runs fine, except now the car not only doesn't hold during cold start, the idle after it warms up bounces. I've already tried taking the system off, didn't do anything. My tps is correct. And I'm pretty sure its not a vaccum leak. Any other suggestions? And I was thinking of messing with the afm, but I don't know how. Can someone please enlighten me on how to adjust the air fuel mixture?

 

Most of the time, emissions removals are done incorrectly so who knows how many vacuum leaks you have or how many crossed lines there are.

Without the BAC valve, the ECU cannot regulate the idle so any load or change on the engine will cause the idle to wander around. Put the BAC back on.

If the idle mixture screw had to be turned full rich to idle the car, there is certainly a vacuum leak.

How did you test the TPS? Is it adjusted to factory spec (1K while closed)?

 

For the tps, I didn't actually do the testing. The original owner had 2 led's hanging out of a connector on the driver side of the engine bay. He said as long as only one of the led's are on, your TPS is fine. In regards of the definite vaccum leaks I have. How would you suggest me to look for them (sorry, I'm really newb)? I forgot to mention my specs are 550s/720s on a rtek 1.7. I don't know if that matters or not.

So for now I should:
1. Put BAC back on
2. Check for vaccum leaks?
3. ???

 

Screw the test LEDs. Test the TPS as per the instructions in the Haynes which show you how to use a meter to check resistance.

An RTek is significant, because it is an adjustable ECU. Perhaps it is just set wrong?