me again lol. my 88 turbo (Japanese engine, ie no egr, no sub zero start) cranks fine about 800 to 1000rpm, then once it warms up. it goes to 1500rpm and stays there. when driving hard and then letting off the throttle, it engines brakes to 750-800rpm, but goes up to 1500rpm when I'm stopped. If I try to lower the idle via the idle adjustment screw, it stays too low (500ish) and surges. Any idea how I can figure What's going on with this thing? thanks again for all the help in the past.

 

My guess is vacuum leak. Which means your hoses are cracked or have come off. You get more air which cause the car to idle higher. There are lots of posts on high idle if you search as well as diagnose with using a combustible or smoke machine. Idle will change when you spray like carb cleaner or brake clear near the leak put smoke though your system to find it. Just google it or search in here as the search works well on the site.

 

thanks for the quick reply. I forgot to mention that the voltage coming from the ECU and going to the BAC is outside of factory spec. But I'm still gonna try the vacuum leak test you recommended. It took so long to get the car running, we,ve been hesitant to screw with any of the electronics lol.