So I got this weird issue.


If I use the AC after starting the car on, the car will bounce at idle for a little bit and then die. I can start it up right away, but I have to turn off the AC for it to be stable at idle. Also I can turn on the AC once I'm driving and moving, but before I pull to a stop, I would need to turn off the AC so the car wont stall.


Now if I turn on the AC before starting the car, 50% of the time idle will be alright and I can drive the car with AC no problem even coming to a stop. The other 50%, car will idle fine with AC but once I start driving and pull to a stop, the car will stall.


Since the car got GSC S2 cams, my tuner told me, it was because of the cams. Is this true?


In addition, sometimes the car will dip very low coming to a stop but never stalled. The CEL P0172 (System too rich - Bank 1) will come on intermittently. The code will turn off by itself, but after a few days will come on again then cycle.


The car is 2011 EVO X and is tuned. Mods are:


EBCS
FIC1100
GSC S2 CAMS
AEM 340 FUEL PUMP
SYNAPSE BOV
K&N HI FLOW FILTER
TEST PIPE
TOPSPEED PRO EXHAUST




Can someone help me?

 

It could be the cams but the tuner should have been able to work around that.....

Check the vacuum line running from the manifold to the FPR:


https://www.evolutionm.net/forums/ev...d-my-idle.html

 

That's the first thing I checked and its zip tied real good.

 

hit it with some spray and soap to see if it bubbles... has to be a leak

 

Didn't find any leak at all..

 

not sure if you got your problem fixed but in my case when ever the AC fan is on it would blow hot air into the intake and the MAF would go crazy so i would build a shield to prevent the hot air from entering the intake and that should fix your problem.I was skeptical at first so what i did to check before building was stick a piece of cardboard in there to separate the intake and the air from the fan and it worked never died again. hope this help apparently its a very common problem.

 

^check this first, then:


Do any other loads at idle cause it to stall/RPM dip?
Turn off a/c, but turn on lights/brights/heater max fan, everything even run the windows open.


If it dies - it sounds like tune to me. The ECU turns up the idle RPMs when the a/c is on (to compensate for the load) but it may not be enough now if the cams are tall enough.

 

The tuner should be able to adjust some tables to fix the issue. Try raising target rpm with ac on through ecu flash.