I am having a terrible time with my '86 2.9l Ranger 5 speed: It will start cold fine and appear to run fine. If I shut down and come back in 20 minutes and start back up, it will stall as soon as the AC compressor kicks on. (I've had this truck since it was new and have always had the AC switch on the dash engaged). Subsequent starts will more or less stabilize as long as I disengage the AC switch, but the idle still seems rough.

The shop who tried to fix it did a lot of work (wires, plugs, rotor, cap, intake gasket) but it still stalls. They wanted to blame the AC compressor but weren't sure. I don't think it's the compressor because the idle is still quite erratic even with the AC off. The compressor engaging is simply putting too much of a load and causing the stall. Just my amateur analysis.

Is there a sensor associated with the function of th AC compressor starting? Can it be replaced independent of the compressor itself (the AC DOES work)? Apparently the shop couldn't find any codes. Maybe my problem is the shop doesn't have a clue how to diagnose an old vehicle like this?

Any help would be greatly appreciated as the truck serves a very usefull purpose despite its age and miles (184,000)

 

The IAC controls the idle speed, it might be sticking and not functioning properly, try cleaning or replaceing.

 

Cool! I'm not a technician, but I'm also not afraid to take something apart. Where is the IAC control and how do I clean it?

 

The IAC (idle air control valve) on a 2.9L is on the passengers side of the upper intake manifold. It looks like a film canister with a tail on the back and two wires. You can clean the valve with carb clean but you have to remove the solenoid (the tail). Since your not real familar with stuff it might be easier for you if you just replace it if it's not to much $$$. I might have a picture if your still not sure what it is.

 

Thanks. I'll give it a shot. I have nothing to lose. Do you have any idea how much an IAC costs? Is it easy to replace (i.e. special tools, pull the engine first , etc.)?

 

I believe it is only two bolts and an electrical connection, don't know the cost.