I want to up my idle when my AC is on by around 250-500rpm's. I know that some jeeps (police, government ones) had this option so does anyone know what mods to the CPU have to be made?...Tj
CF Veteran
You're probably thinking of the "Extended Idle" switch - which set the idle up around 1000rpm by pressing a switch on the dashboard (mainly to provide additional alternator output, to drive lights/radio/&c on police models.)
I believe it's wired into pretty much any OBD-II PCM - the problem is that your 1994 is OBD-I. You'll find the mod covered in fair detail on NAXJA.
As far as a full DIY version, you may have trouble. You'll need to either have access to the stepper motor that controls the idle (the IAC - which already opens up slightly to keep the idle up with aircon load on,) possibly find a way to fool the PCM into thinking the aircon is on when it isn't (I haven't looked into this,) or use a friction-lock control cable to make a bypass hand throttle (these can be had at most industrial equipment supply houses - I used to put them on forklifts often to give better hydraulic performance at idle.)
I believe it's wired into pretty much any OBD-II PCM - the problem is that your 1994 is OBD-I. You'll find the mod covered in fair detail on NAXJA.
As far as a full DIY version, you may have trouble. You'll need to either have access to the stepper motor that controls the idle (the IAC - which already opens up slightly to keep the idle up with aircon load on,) possibly find a way to fool the PCM into thinking the aircon is on when it isn't (I haven't looked into this,) or use a friction-lock control cable to make a bypass hand throttle (these can be had at most industrial equipment supply houses - I used to put them on forklifts often to give better hydraulic performance at idle.)
Thanks for the reply, I'll have to do some research on this. I will write back on my findings, if any at all...Tj