I had to take the Evo out in the snow and salt yesterday. After I was done I decided to take it to a touchless automatic car wash. Just good enough to get most the salt off the car.

While in the wash my engine began random surges up to 1500rpm. It was already at full warm up and idling around 700-800 like normal. Everyone in the car noticed that it only seemed to surge when the spraying was at the front passenger side of the car. It was a slow surge and decline back to normal. Like it was computer controlled. Sprayer got the front right and it would climb to 1500 very smoothly and hold for about a half second then very smoothly decline back down to 700-800.

I can't think of any GOOD reason as to why this would happen. Maybe water mist was entering the intake...???

Extra info: I have the Works reflash and axle-back exhaust. Nothing else. I had the heater on (set on blowing out the dash on to the windows) and the fan set on "1". My headlights were on and so was the CD player.

 

Bump. Any ideas?

 

I think you answered your own question right there.

Those touchless car washes blow water at very high psi....as a result it creates a very fine mist that just hangs in the air. That moisture could get into your engine and effect the firing of the cylinders.

Don't sweat it though...taking in water vapor r mist won't hurt anything in the long run.

SC~

 

Just curious, mine will do the same when I have the front defroster on. My idle will spike to 1200-1500 at a light if I have the front defroster on. I suspect that it is the compressor. It should be fine.

 

Mine was doing the same thing this morning.

It happen as soon as my GF turned on the defroster.

Every stop light it would go from 850rpm to about 1200, then lower itself.

 

Is this happening to anyone else.

Does anyone have an explanation?

 

Happens to me too. It never happened when it was warm outside, dont know if that helps.

 

It's normal.

 

On some cars, using the defroster also engages the A/C.
You want to blow dry air on the window to get rid of any fog on the inside.
Perhaps this is what is happening with the Evo.
To test, turn on the defroster and go look under the hood to see if the A/C clutch engages.

 

The Evo's A/C is engaged with the defroster...

 

i know what it is....its your fan on your car turning off and on...listen closely and you will here it kick on and off when you notice this surge.

 

It's the a/c kicking on. It comes on whenever you are past the footwell/front defrost mark on the fan direction dial, or if you click the a/c button on manually of course. I really wish it would just light up the a/c button for you, allowing you to turn it off because most of the time I don't need my air "conditioned" for defrosting purposes (i.e. removing 3" of ice from the windshield).

 

It is true, its the A/C kicking on, look in the owners guide book

 

I hate that too... even more so is the recirculation turning off... Damn it, I want the recir. on almost all the time. The driver is supposed to control the vehicle damn it! I'm about to tear the dash apart and start cutting and splicing (end of rant )...