please help with idle and dying issue on my 89 TII
 

I am trying to get my fc to where I need it. I bought it a few months ago and have been fixing everything, But Im not able to figure this out yet. It is hard to start and will turn over a few times before it starts and if it starts and stalls it wont start back up for a few seconds. it will idle after that but at around 5-600. then when your driving it will die when your sitting at a light or stop sign. Its really getting on my nerves. Here is whats done to the car.

adjusted the TPS sensor
installed new battery
installed new starter
has a fd alternator that was just tested out fine
belts are all tight and some are new.

has no cat just dp and rb catback.
no air pump
no cold start system ( I know thats prob a big thing LOL)
and other emissions are removed ( how I got it)
has a cheap k&n filter on maf sensor.
boost hits at 5 and creeps up to 6-7
seems to have good vacuum at around 15


Im not sure whats going on with it but just figured I would be able to get some help. I have searched and I am mainly getting s4 stuff nothing that seems to really apply to my car. anything you can tell me would help alot

A metered air leak at the TID or a vacuum leak can cause that.

any advice on how to check and or fix would be helpful as well

Air leaks can be found easily on a car that only idles at 500-600 rpm or so. Buy two cans of starter fluid. Warm the engine fully. Then spray around the engine in all the obvious places. Like you would not spray the water pump but would spray around the vacuum lines and mating surfaces of the intake manifolds and spray around the rear of the intake where there are numerous vacuum lines on a turbo engine and a couple on a non turbo engine.

A car that idles at 500rpm when fully warmed up either has no BAC or the plug is off the BAC or the transistor inside the ECU that drives the BAC is kaput. The BAC can be called a Idle Air Control Valve ............if you wanna and can't figure out what bypass air control does for the idle on a car. Whatever.

The TURBO BAC has an air adjustment screw, unlike the non turbo BAC. That screw aids in obtaining an idle of approx 750-800rpm at idle. When a LOAD is put on the engine the idle will go down if a BAC does not exist. The BAC senses the LOAD and adds air by upping it's duty cycle to maintain a 750-800 rpms idle.

Warm the engine up. Idle the engine. Pull the elect plug off your BAC. On most, but not all engines, doing this will cause the idle to drop a noticable bit of rpm. If yours does not, then suspect the BAC as being PART of your idle problems. Probably NOT a bad BAC itself, but a busted transistor in the ECU. Seems you'd get a fault code for that . I'm not sure about that part. The ECU might just look for resistance thru the BAC coil and only chunk out a code fault if it sees the BAC disconnected or having an open wire in its circuit.

I did the starter fluid tonight and wasnt able to get a response. anyone have a picture of the bac? and highlight the adjustments? or w/e thanks.