alright so yesterday i seafoamed my truck (01 4x4 sohc 4.0l) and it ran alot better. it even lowered the idle which was at 1200 down to like 6-700 but this morning i drove to school and it ran fine but after school it was a lil warm so put my AC on (which hasnt been run since like oct.) and it idles real rough like their is a vacum leak but only with AC on and the engines rpms drop to like 200 and it almost dies. so ive got to figure this out soon cuz if my dad finds out he will say its becaus of the seafoam which he told me not to use but i did anyways cuz i trusted you guys.
So What is Causing this???

 

there is no way the sea foam did that to your AC. check around your ac canister for vaccum leaks.

if can be done with smoke

 

i know seafoam did nothing to it. the canister looked wet but i think it was condensation cuz it didnt smell like anything
anyone else know what the prob. could be?

 

IAC controls Idle. When the Air Cond is turned on, the IAC should compensatefor that load.

Disconnect the IAC electrical connector with the AC running.

If the idle doesn't change, replace the IAC.

 

actually today it started doing this all the time and its makin me go mad so looked under the hood while it was running and the pully on the water pump? which has like a clutch looking thing with like 3 bolts when it engages the idle drops to like 200 rpms and the engine almost dies but then disengages almost imediately and the rpms rise again
is the waterpump going out or is this the IAC ?????

 

thats the AC compressor your describing

 

but now its doing this with the AC offis it still the AC compressor
i was thinking now more along the lines of MAF or IAC because i have a K&N filter that may have gotten one of them oily and dirty how can i clean them just use that electronis cleaner compressed air??

 

oh and when i drive on the highway their is a high pitched squeeling noise but its only at like 22-2700 rpms

 

anyone?

 

i have a whistling noise around that RPM range under steady throttle, it's not loud, many don't notice it but i know it's there.
Could you be hearing that?

 

clean the IAC and the MAF sensor. use brake cleaner on the MAF and lightly spray the coils and let them dry completly. when you clean the IAC hold it with the round motor up so cleaner doesnt get in the motor. also, disconnect the battery for like 15 minutes to reset the computer if this doesnt work then i would replace the IAC motor.

Another thought, remove the belt and spin each pulley by hand and see if one of them is noisy causing your high pitched squeal. Start the truck (cold motor) turn the a/c on with no belt on it. if the idle changes then you will know that it is not from the load of the a/c compressor and is most likely not an IAC motor. if the idle doesnt change when the belt is off and the a/c is on then it is most likely the IAC.

 

Hi Guys. New member here. Forgive my ignorance, but I was curious as to what IAC stands for.

 

do you think that there is any way possible you could be talking about the fan clutch?

 

same here. maybe the fan is locked up. You can take the fan off and start it to see if it makes a difference.


Jason, Its the idle air control. it allows some air into the Throtttle Body at idle to adjust it up or down.

 

no i know the noise is there and other people that ride in my truck hear it as well so its not just me
ill clean the IAC and MAF that will probably fix it
its not the fan clutch
and just to make sure the IAC is mounted on top of the throttle body
how do i take off the MAF because its a torx bolt with a little nipple or bump inside it
and i use brake cleaner to clean them like BRAKELEAN?

 

that is what leads me to believe your fan clutch is bad. but to check it do this. while the truck is off try and turn the fan with your hand if it won't turn then your fan clutch is bad and that is your problem

 

The squeel is probably more likely a pulley or a loose serpentine belt then the fan clutch. I've had fan clutches go out both ways: "fully locked up" & "no resistance". Both of which never resulted in a squeel condition.

As for your idling problem under load, do what was stated here earlier: Run the truck without the A/C belt on and go inside the cab and turn on the A/C. If the idle DOES NOT go up it's more then likely your IAC valve assembly.

I.A.C.=Idle Air Control Valve

Controlls the engine rpm's, particularly while under a load, hence A/C.




Allen

 

I'm going to go with the IAC, as I had the same problem. Good luck cleaning it, I ended up replacing mine.

 

IAC only is on when the engin is at an idle.. idle air control.. when the throttle is open it is not being used.. ur voltage regulator plays a hand in keeping the engin alive when loads are turned on..

 

thanks guys ill have to try all that today