03-30-2020, 03:05 AM
(03-29-2020, 09:09 PM)fixkick Wrote:(03-29-2020, 05:23 PM)TracyDJMan Wrote: I’ve got a 91 2 door with manual transmission. The idle speed increases when I turn on the AC, but doesn’t rise when the heat is turned on, or headlights, or steering wheel is turned at idle. This is a huge mystery to me. I tend to use my vehicle as a mobile work light so being able to keep the battery charged at idle with lights on is super useful. Cheers!
that is because it is NOT a 89/90 car.
and you are reading the wrong manual for 89/90 and not the correct 91.
91+ all 91s and newer only race idle speeds at AC and overload PS pump (sensor switch)
that is it.
this ended because the ISC faster and more powerful, now.
and can hold 800 RPM perfectly under all condition motor hot normal temperature.
and they DO.
the Generator alternator no problem at all running stock lighting ever, at 800 RPM (a fact)
so my guess is your car has a problem of somekind but I am not sure what, not stated yet.
Interesting. That’s good to be aware of, but my idle speed does drop when any of those things are done. Is that normal? It doesn’t hold 800 under load, other than AC. I don’t and never have had any stalling issues, so maybe everything is okay. It seems to typically run around 600ish under load. Also I have the 91 Geo Tracker manual which states the idle speed should rise to 920. I’ll take that as a typo.