ShapeGSX

EGTs are pointless anyway. There are too many factors that determine the EGT, and they don't really tell you what the combustion chamber temp is anyway.

DCsleeper

iTrader: (11)

Useless reply, but at least its a bump. If you read this read check out my previous post.

EVOTEXAS

iTrader: (12)

The AC DOES use vacuum, whether or not the AC shutting off at a throttle position is my problem I do not know, though I suspect you are right about that.

maki

iTrader: (7)

lean, check your afr

ShapeGSX

How does the A/C use vacuum?

EVOTEXAS

iTrader: (12)

It uses vacuum to run. The engine also uses vacuum to run. They share. Easy way to check. Look at your boost gauge with the AC off. Then turn it on. Less vacuum. Everything uses vacuum.

ShapeGSX

That isn't the way it works. The A/C puts more load on the engine, which causes the RPMs to fall. So the ECU opens the idle stepper controller more to allow more air into the intake manifold until the correct idle RPM is reached. This is what causes the vacuum to drop. It is because the ECU is trying to maintain a certain RPM, not because the A/C is using the vacuum.

The brake booster "uses vacuum." It has a direct connection to the intake manifold. When you left foot brake a lot and generate some boost in the manifold, you can actually feel your brakes start to go away as a result.

The A/C compressor has no direct connection to the intake manifold.

EVOTEXAS

iTrader: (12)

I never said it was connected to the intake manifold. I said it takes vacuum to run. Which it does. This is a fairly pointless argument.

mhgsx

iTrader: (6)

I can think of 2 ideas.

I'll assume that your headgasket is fine.


First, take the car to a pressure washer and try to spray from the inside out your radiator and intercooler. You'll probably have to remove the radiator shroud.


Second, flush the coolant. It could be that the factory f**ked up and didn't put the proper dilution.

V8 HUNTR

dude, I live in Arlington, right outside of DC. What dealership did you go to ??? (PLEASE DONT SAY STHOLMAN). If you dont get this figured out, i'll help ya man, i know how hard it is when your car is ***ed up and you dont know whats wrong !!! shoot me a PM.

- Taylor

DRFTKNGG

iTrader: (8)

Actually, the compressor clutch disengages to prolong the life of the compressor. Every new car does this. The ECU knows when you floor it, and then turns of the compressor, untill you let up. Then it engages again. It's called a A/C compressor clutch.

ShapeGSX

I just want to reiterate that the A/C compressor does not use engine vacuum to run.

Zeus

iTrader: (66)

I must admit I also thought "what in the hell?".

EVOTEXAS

iTrader: (12)

Ok how about this wording? The AC prevents the engine from creating as much vacuum when it is running. Better?

DCsleeper

iTrader: (11)

Hey guys,

Thanks for all the responses. Haven't checked this post out lately. The problem has been fixed. Talyor, your right never going to Stoleman again. Gave me a good deal on the car, but thier service department is horrible. Did however find a good mechanic at Sheey in Waldorf (not that there service department is any good either, but they do have good mechanics).

Back to the problem. Turns out that our Evo's have two temperature sensors. One which the computer uses and one which just sends a signal back to the temp gauge on the dash. Took the mechanic out for a ride and ran through the first 3 gears on 301 while the mechanic took readings from the ECU. Turns out that when the temp gauge spiked the ECU still said that the engine was running at a normal temp. Hence, failed temperature sensor. Replaced and have never had a problem since.

Again, thanks for all the support