A.C. fast idle setting

[David_Jennings]

My brother's 89 k2500 6.2 stalls when the A.C. is turned on. The fast-idle works at start-up, but doesn't seem to kick in when the A.C. is turned on. Is there an adjustment or fix? Thanks.

[john8662]

There wasn't any circuit on these engines that engages the fast idle when the A/C was engaged. Although, it's not a bad idea to make a way to do so.

So when you say that the engine stalls, do you mean it dies?

auto or manual tranny?

First, get down to why the A/C causes the engine to stall. I'd think that the engine idle speed is set too low, it should be 650RPM when up to operating temperature. If you're setting this w/o a tach, it's going to be by ear. I have a picture that I can post that shows the appropriate screw to turn on the injection pump to adjust the idle speed.

[84 C2B2]

I retro-fitted a system with separate wiring harnesses to my 84 K30. The wire that feeds the compressor also has a fast idle "green" wire but it is too short. I imagine itr was for an original gasser. I plan on adding to it's length and placing a diode in both "green" fast idle power lines. This way I will have fast idle for the A/C and for cold start without energizing both circuits. I'll take a look later on today and see where this A/C green wire is routed from and get back with you.

Jerry

[BobND]

I think you will find the original "throttle kicker solenoid" does NOT have enough power to kick the throttle open by itself, only enough to hold it open after you've had your foot on the "gas", and then released it, as you do do upon startup.

If it were idleing, and the AC kicked on, I don't think the original solenoid could speed up the idle on it's own.

The IP's internal governor should sense the drop in speed with the added load of the AC, and bring the idle speed back up to where it was before the AC kicked in.


Perhaps the little idle spring inside the main governor spring is broken, or jammed?

[David_Jennings]

My brother put in a different refrigerant, which was apparantly solved the problem. (He went back to R12?) Thanks for the help on this. Now he has another problem he wants me to post. Since I sold him the truck, I am obligated. (He joined, but doesn't like to use the computer.)