1995 quest, engine stalls when AC is on, or when front defroster is on.

[nissanquest95]

When fan speed is at 1, car at idle, turning on AC or front defroster can stall the vehicle, sometimes a loud screeching noise can be heard right before the stall.

All drive belts are brand new.

But when the fan speed is at level 4, stall may or may not occur with AC or front defroster turns on.

I used a consult to monitor the engine, and noticed IACV-AAC /V increased from 30% to 80%, IGN Timing decreased from 55 BTDC to 35 BTDC, and INJ Pulse increased from 3 to 16 msecs right before engine stalls:

Idle - normal

AC turns on, right before engine stalls completely.

What could be the problem?

[VStar650CL]

The changes in the engine parameters are from the ECM desperately trying to prevent the stall. Notice that the MAF drops way off but the ECM throws the injectors way rich. Since having the fan already running prevents the stall, I'd say the combined, sudden load from the compressor and alternator is causing the stall. That means either your FICD or AAC probably isn't working, most likely the FICD. Use "Active Test" mode in the Consult to test the AAC, if that works then most likely your FICD solenoid or valve is inop.

[nissanquest95]

The particular conzult software I have has active test for AAC, and it appears to be working ok.

I set it to different level up to 100, the engine definitely feels running differently. I suppose this means the AAC is working ok.

Is there a another way to test the FICD? Also, I can't find any replacement parts for FICD, is the failure usually due to clogged solenoid or some spring? Is it possible to fix?

[VStar650CL]

I haven't looked it up and the Quests may be oddballs, but on everything else from that period, the FICD is a solenoid built into the AAC/IACV but separate from it functionally. The only way I know to test it is to power the solenoid pins directly with the connector loose and see if the idle increases.