1987 fj60 runs bad with ac on

[patricio]

My 1987 fj60 runs very poorly with the air conditioner on. When it's idling the engine revs between 1.5 and 2 rpms. and the engine sputters a lot while driving. Any help would be great.

 

[Tinker]

Do you have the FSM? Part of the AC controls increase the idle on the carb (I know I'm not using the correct terms by my FSM is at work). There's a debug procedure for just this problem.

Also, your AC system could be FUd: compressor, clutch, belt, etc.

 

[chitown40]

The revving is caused by the a/c idle screw being adjusted too far in. If the engine is sputtering, that can be a whole other issue. Your compressor could be starting to seize up or something as easy as a poorly adjusted carb or carb needing a rebuild. Fix the a/c idle up screw (on the front on the carb) by loosening it a turn or two until the idle is where you want it and not surging, then look into the sputtering problem.

 

[Marc311]

x2.

You want the idle to be about 1000 rpm when the AC is on. If it is adjusted too high, it does exactly what you describe - races to about 2K and drops (I presume from a loss of vacuum which in turn effects the AC Idle Up Circuit).

Not sure about the sputtering. Were you adjusting anything or moving hoses before this happened?

 

[hank14]

The sputtering may be an unrelated vacuum leak- possibly in the hose from the A/C idle up solenoid to the carburetor?

I assume it runs fine and is in good tune when the A/C is off?