Does the high idle spike occur when the AC compressor turns off?

George

 

Yes exactly the RPMs will go up when it turns off. Here I took a video of it today. Let me put this into context. The start is right after driving it for a little bit and I just got home, the idle was high, then I turned on the AC and the idle went to 650. Then I turned off the AC and the idle went back up. Turn off the AC again and it went back down to 650. Then I turned the truck off and started it back up and it idled at 650 with no AC on, I turned the AC on and it jumped up for a second then back to 650.

 

Sorry, I see that you already answered the AC question, I was using my phone earlier.

I forgot to add servicing the EGR valve if needed if so equipped.

The question is if the AC compressor is presenting an unusually light or heavy load, confusing or limiting the IAC control or is it just putting into motion a poor IAC control situation? If you have a set of gauges you should check your high and low side pressures.

Then its on to the rest of the list. Easy peasey.

George

 

No egr valve for me, I don’t have gauges to check ac pressure unfortunately.

 

Some information can be obtained about the AC system without gauges. Put one of those cheap dial auto AC thermometers in the center dash outlet at full fan speed and cooling. If you get close to the green temp range, you probably have enough gas. If the compressor cycles after it starts cooling down then your probably not overcharged. These are just crude estimates.


George