Are there any other settings required to lock SA at idle other than checking "Option Word 2, bit 12 -IdlSa" and putting a value in "SA - Idle State SA"?

I have done both and set my idle state SA at 20*, but after the car is warmed up SA bounces around between 15* and 22*. Are there other SA adjustments in play?

Car idles in the 42-44 KPa range at 575-625 RPM in park. All of the 500 and 600 RPM cells in the SA Main Table are set at 20*. The 800 RPM cells are around 28* in the idle KPa area, but i never see it idle over 625 RPM, so I wouldn't think that's causing the issue. In any event, the IdlSa bit is supposed to cause the ECM to ignore the SA Table if I understand right.

SA moves in a much tighter range (19-22*) during warm-up period after I start the engine cold. It's definitely happier without the SA moving around.

 

Researched further and figured out how to fix when the engine is warmed up - zero out the SA - Idle High and SA- Idle low tables. Engine more stable, but slightly rich. Will fix idle VE now. I hate how the answer suddenly appears after you post your question!

New Question: when I fired up the engine warm (around 100* F), SA was 21*, then decayed to 15* and slowly rose back up to 20* as the engine warmed up to operating temp. Engine didn't like the lower SA during warm up. How do I fix that?

 

Yes, the idle compensation SA tables.

As for the change in SA during warm up, look at the "SA - Coolant Comp Spark Advance" table. The lower SA area in the mid KPa vacuum of that table is to help kick off the cat-con. But this won't affect idle, only an off idle running engine.

RBob.