I forgot got to mention that i have hks 272's on my car with cam gears set at -4,-1.5. just threw that out there.Im gonna keep an eye on this thread to see if you find a solution.

 

Well still no luck fixing the issue. Someone posted on here and said they have the exact same problem without cams. What else do you have? The next thing I am gonna try is to clean the MAF sensor. You might want to try the same. Heres the link.
https://www.evolutionm.net/forums/sh...ight=clean+maf

 

I have the basics TBE, Drop in filter and upgraded FMIC/IC pipes. I also have a twin disc clutch with a light weight flywheel. I started having the problem after the clutch was installed. The car stalls out very rarely but the rpms always bog once the clutch is disengaged. I used to have an ECU+ piggyback and with that in the loop the car would stall every day with the AC on (only after the clutch). I think the piggyback delayed the MAF signal a little exaggerating the situation.

 

bump

 

Hotredevo I am having the same problem with my 9 as well. Mine started when I got my Exedy twin plate clutch. However before the clutch I noticed the car would stumble at times too but would not stall like it does now.

I have heard that the idle air control (IAC) could be the cause of the problem. They are made of plastic and can melt, which in turn can cause a problem like this. I am replacing mine on Wednesday. I will let you know if it solves the problem.

 

Yeah, same here...I didn't notice it right away after the twin install since it was cold out, but once summer hit and I began using the ac I have the problem....last year had no problems.

 

Bump idle timing, make the ISCV for AC on match AC off in both the drive and neutral maps, and verify that MIVEC is 0* advance at idle. With the Cossies I would set my idle timing about 10* as long as you dont start getting a P030x code maybe a little more. Set your idle settings a little higher as well. I have set them to 1000 before and got fairly decent idle out of the Cossies. My S1's lope with 0* advance (I wonder if they were misboxed S2's almost) where everyone else says that they dont even notice them. I have played around with it and its fine in all rpm ranges/driving conditions. When I get home from work I will post the sections that are pertinent to your problem.

 

I was helping him, tired everything i could think of from the ECU. I think its something mechanical.

 

Any word on this? I am having the same problem. Idle is great with the AC off and goes all to hell with it on... I tried bumnping the idle from 953 to 1000 and the car would actually shut off when I turned the AC on. I put it back to 953 with my ISCV at 77C 120 82C 110. The car idles GREAT with the AC off 14.2-14.8AFR but when the air is on and I am rolling the car runs very rich in the 9's and I noticed in evoscan my timing drops down to about 5*... The odd part is there is not 5* cell on my High Octane Ignition Map... There is on the low map but not high...

 

What timing are you guys running at idle? I don't have cams nor a lightweight flywheel and my car will stall or stumble with the AC on when I push the clutch in and brake. I think the stalling/stumbling has to do with braking because the brake system runs off of vacuum. The engine is struggling more when AC is on and the brake booster takes away the resources the engine needs so it chokes.

That being said, this problem didn't come up until I raised my idle timing.

 

After some research I think the Maf scaling is playing a part.

 

My timing drops from about 16* to 5* then the car shiats on itself.

 

I had this stalling problem after installing a set of cams (incorrectly). Basically there wasn't enough vacuum in the intake manifold. This caused issues with the MAF reading and forced the ECU to idle on open loop. Incidentally, fuel trims still looked OK. I suggest everyone with a stalling problem check their idle vacuum to see if the problem lies here. My vacuum at idle was -.28 to -.3 bar (4 to 4.35 imperial measurement I think). After fixing the cam timing vacuum is -.4bar and everything is sorted.

 

my idle is at -70ish ac off and -50 to -60ish with it on... the step iscv helped but u can not make quick gas and clutch in or the car is fawkt. my idle also goes up to 2k sometimes with the ac on. basically wit the ac on thre car has a mind of its own.. lol its like a box of chocolate u never know what ur going to get...those readings are from my greddy edc and I am not sure what they represent... it is also a digital boost guage... I get the positive numbers like 235 means 23.5psi but -70 means? who knows.... when the car dies I have seen it go down to -28...

 

is there a differen ig timing setting for ac on?