88t2

I am having a problem with the idle not holding with the A/C on. When I turn on the A/C the idle will go up to about 1200 then come down to 1000 (my normal idle). Sometimes it will hold it there for a few seconds then fall until it stalls, other times it just drops from the 1200 to stall. With the a/c off, I can uplug the isc and it makes no change to the idle . I tested the voltage going to the isc with key on - engine off and I get nothing. I even checked it at the PFC, still nothing. Manual says it should be 8-11v at this stage (for the stock computer). Does the PFC do the same? Could the PFC have a bad idle circuit? With the a/c off, the car will sometimes stick at a 1400 idle but if you blip the throttle once or twice it will fall to the 1000. I have tested the resistance of the isc back several months ago when I was having the common idle problem, but it was in spec. I think this may have been the problem all along. I never hear it humming as some have said when you turn the key on. I took it off and tested it with 12v and it clicks as it should so I know it is good.

Thanks for any help you can provide.

info:
94 base, single turbo, 3.5" ehaust, walbro fp, 1600cc sec, FMIC

cewrx7r1

iTrader: (2)

Ajust one of the mechanical idle adjsutements. Play with it and learn how it reacts.

Do a search.

Turn off O2 control.

This type of question is asked more than any other question since the PFC came out! It is getting very boring and redundant!

88t2

I know the idle setting question is the "most asked question" and I did NOT ask HOW to set the idle. I did do a search on ISC voltage and there were no relating responses.

I asked if the PFC puts voltage to the ISC with the key on - engine off like the stock computer is supposed to.

I have the O2 control off.

cewrx7r1

iTrader: (2)

" am having a problem with the idle not holding with the A/C on. When I turn on the A/C the idle will go up to about 1200 then come down to 1000 (my normal idle). Sometimes it will hold it there for a few seconds then fall until it stalls, other times it just drops from the 1200 to stall."

This means the PFC is doing something with the ISC other wise the idle would be stable at some rpm. To do this a voltage has to be applied to the ISC solenoid.

" tested the voltage going to the isc with key on - engine off and I get nothing. I even checked it at the PFC, still nothing. Manual says it should be 8-11v "

Some functions only work with the engine running, not just turned on. The fuel pump is one of them. Have you checked it with the engine running?

"With the a/c off, the car will sometimes stick at a 1400 idle but if you blip the throttle once or twice it will fall to the 1000."

An ISC/idle controll problem or sticking throttle.

Try this; remove the ISC solenoid, connect wires to its connector so you can engergize it, emerse it in some type of cleaning fluid, cycle the solenoid. If I connect mine to my batter charger, it will buzz (constantly open and close) because the voltage is not pure DC but pulsating (square wave) DC.

This will help clean any dirt from the valve that may be causing it to stick.
Also check for the sticking throttle.


Now do you like these suggestions?