High idle and no turbo timer

So, as my friend and I travel down the seemingly never ending road to fixing his DSM, we hit another problem right as we are about to get the bitch on the road. We got it running with new plugs and it starts and now it starts and runs fine but has a high idle. When we got it it had about a 800-900 RPM idle, today it was around 1500. What could have happened? We fixed the oil leak, new t case fluid, plugs, new oil and filter, new battery, and we have a 3" down pipe on. The exhaust is just running straight out the down pipe, could that have any affect on the idle? When we replaced the battery we obviously had to disconnect the old battery. We didnt reset the turbo timer (because we dont know how) could this be why its not idling right? Its a HKS turbo timer. I have no idea what could be going on. Thanks in advance guys, we appreciate all your help.

Throttle body adjustment maybe? Or even timing possibly, turbo timer wouldnt have anything to do with it I dont think neways

try adjusting it with the BISS screw

Ok. Why would the idle just go up like that?

yeah seriously just adjust the BISS screw, my idle did the same thing last year and i adjusted it and its been fine sinse

Is the BISS screw the same thing as the idle speed control? Is this screw is plain view? Is it on the throttle body? Should we adjust it, THEN turn on the car or turn the car on the adjust it while the engine is running? Thanks again guys.

MY car idles at 1500 when its hot and 900 when its cold or just warm. It's crazy. The screw is located right next to the isc. It might have a little rubber stopper on top of it. Just turn the car on and adjust that screw until your car gets to the right area

Ok thanks everybody, we appreciate it!