91 240sx: Having trouble setting timing(TPS or IACV)

[1WheelWonder]

The other night I made an attempt to set and adjust timing if needed. I followed the procedures correctly by warming the car, pulling the tps and setting idle to 700-750 rpms. However, my car would not idle properly below 800 rpms with the tps unplugged, the rpms would surge up and down and eventually stall out. Therefore no timing adjustments were made, I just plugged the tps back up and said forget it. The car has always idled flawlessly with the tps plugged in. I figured it could either be the TPS sensor or the IACV, is there a proper way to check or clean these items. Any help will be appreciated.

Chris

[NISTECH]

Heres the deal with it unplugged the car goes into none computer control for idle and timing if one is already adjusted too low it will do that. try turning the idle screw out a bit before you do it with the tps unplugged. After you bump the idle up try the procedure again. If your idle was already slightly high with it plugged in you probably have a air leak somewhere [vaccum leak]. See if that helps ya.

[1WheelWonder]

My idle is normally around 850-900rpms and as far as vac leaks go there are none to speak of, I sit around -21/22 at idle. With the tps unplugged and idle at 800rpms is it going to affect timing much to set it there. I am wanting to retard it a few degrees for boost.

[NISTECH]

no your spec is around 750 so up or down 50 wont effect it.

[1WheelWonder]

Thanks NISTECH you the man.