Hello all,

Lemme start by saying yaayyyy!!! Back in a Rotary. Originally had a 91 Gtu. 8 years later and now I'm back. 89 Turbo II (my dream), runs great when shes warm, wont idle or stay running cold, even after it warms it has a chaotic idle. Usually will float around the 1600rpm range. I've had it for a year, put a new motor and trans from jspec auto in it (still had the problem). 3" racing beat exhaust from turbo to hks cat back. No other mods. P/s and A/c are gone, as well as Idle air control and emissions components, there is also a significant exhaust leak at the turbo where the downpipe mounts due to poor machining of a wastgate dump plate. This may just be an issue I have to deal with til I buy the engine management I want, but I dont know for sure if it could just be the exhaust leak, map sensor goin out. I've seen other turbo rex's idle with no problem without a IAC and come to find out it was simple throttle body adjustments. Any advice would be great.

Thanks.

 

Removing the BAC and thermowax means you're going to have to give it some throttle cold. That's all there is to it. This is a big reason to not remove those things.

After warming up, if the idle bounces it is most likely one of two things: vacuum leak/air leak or TPS out of adjustment/bad.

 

Just today , Found a vacuum going to nothing, and adjusted the TPS. Does not idle erratic anymore now.

 

Do yourself a favor and put the BAC back on. There's no reason to remove it.

 

^ I second that.

 

After re-installing said BAC, still has the same problem...how do I troubleshoot the component for functionality??? or have I just kinda done that...

 

Vacuum leaks? During emissions removals, many people mess up the vacuum system so badly that the car doesn't run correctly ever again without a total vacuum system replacement. Idle problems are almost always vacuum related.

There are instructions for testing the BAC in the Haynes and FSM.