i set my commanded idle speed in tune to 700 as i could not get car to stable idle at 800. seemed to want to idle around 850-900. no help. IAC counts were coming and going with surguing resulting. seems this isue is not all that uncommon?

i attempted to remove IAC from issue by setting idle speed by throttle blade position and setting commanded way low to 600. this seemed to help stabilize idle somewhat. i think i have other issue affecting a pulsating idle(low BPW problem) as well.

now the Q is does setting commanded idle speed way low affect the A/F ratio at idle in CL? i am CL at idle. does the ECU command a leaner A/F at 600 than say 800 rpms idle speed? again assuming IAC counts are sitting at 0 even when engine idle pulsates.

ps. seems when OL and choke timed out(130-159F) the idle is super smooth at 750 !! CL invoke is obvious...

 

No connection between IAC and closed loop fueling. To set the closed loop fueling for idle set the O2 window terms to match the open loop AFR as read by the WB.

Hook up the WB and just before it goes closed loop record the AFR as reported by the WB. Or just force open loop and do this at normal operating temperature.

Then go closed loop and adjust the O2 window to give the same (or close) idle AFR as reported by the WB. During idle both the normal O2 tables are used along with the idle offset term at $2F7.

It can also help closed loop hold tighter control over the idle AFR by setting $2FC to 255. Setting the idle proportional gain at $2F9 lower can also help.

RBob.

 

i have not yet leared hex editing. will look over the tunercat tables or contact them for an upgrade. thanks.