As the post says, GSC S1 Users, past and present (particularly those with non-MIVEC)... Question for you.

I just got S1 installed on my 2003 Evo 8 (and a tune of course), the idle is rough as a mother eff'er, and the car has a tendency to randomly stall itself out when I pop in the clutch as I am decelerating (like for a turn into a store's parking lot for example).

The car only seems to have an issue in idle though. It pulls like a train on accelerations, and has no problem with driveability when the clutch is disengaged. Essentially, it is just idle that it seems to have an issue. The issue isn't consistent either, let say it happen every fourth time I pop in the clutch, or sometimes every third, or fifth... get what I am saying. It happens often, but not everytime. And, when the A/C is on it happens twice as much (no shocker).

Here go the questions:

1) Compared to stock cams, I was under the impression S1 were only very mildly lobey and could be tuned at idle damn-near stock. Is this true?

2) What do you think from the description.... Is this a cam issue? A tune issue (what I am leaning towards)? Or, an Idle Control Motor issue? Or, maybe something else all together...

Any help would be greatly appreciated!

 

you cant even tell my car has cams in it with s1's, it idles as smooth as stock

i would try setting the idle using the speed adj. screw mode in evoscan. that is most likely your probelms with the stalling out issues especially with the A/C on

 

You have a 9 though. From what I've read cams are more noticable on an 8. I have s1's and the idle is a little lopey but I have no stalling issues.

 

Check the tune. My tuner left some lope in cause some people like it, but let me know if I didn't like it they could change it easily. It's not bad and has never caused me any problems, but I definetly need to give it a little more gas when the AC is on. Good luck.

 

To fix your issue, while the car is on, turn the BISS screw on the throttle body 2.5/3 turns counter-clockwise (do it in increments). Then use Evoscan and hit activate on 'speed screw solenoid' (after each time you adjust the screw) and it should idle just fine. Only keep adjusting it until it idles pretty well.

Also, what is your base idle set at?



-Bink

 

I installed the S1's in my 8 and I had the same issue.The problem was I install the
cam angle sensor trigger wheel 180 degrees out.
Swapped it and stalling went away.
The idle lopes abit but not too bad.
I never adjusted the Biss screw to keep it idling correctly.

 

this or your timing is off. you shouldnt have to mess with your biss screw. after you pull the grenade pin on your hydraulic tensioner you need to cycle the rotating assembly a couple times so it creates enough tension. if you forget, you can skip a tooth on startup. but you def have a timing issue. the car should idle basically like stock with those cams. good luck!

 

Mine was rough at first and loped a little much, I tried to adjust the Biss screw but as usual I mess things up and took it back to the tuner and he smoothed it out. Additionally my bov was bad and after replacing it it smoothed out more. Just slightly rougher then stock at idle. When I installed them though I picked up over 60whp on the top end.

 

Thanks for all the input.

To answer some questions and provide some additional information...

Idle is sitting (or supposed to be sitting) at 1K rpm.

Additional info: car smell of unburnt gas after initial start... smell usually hangs around for about a minute. It is just strange because it has never smelled like that before.

 

Take it back to your tuner. Ask them to smooth it out.

 

^Thanks! That was my thought too. I just wanted to make sure there wasn't any underlying issue.

 

Did you try adjusting the BISS screw?

The bigger the cams, the more air the car needs. Turning the screw gives it the air that it needs. I'd try that before going back to your tuner. Besides, he'll probably say the same thing.


Take it from me, who just had the same issue except with GSC S3's.



-Bink

 

had same issue in my car, a local tuner adjusted it and it ran great even with AC on

 

Thanks for all the input, everyone!

Here is what the conclusion was --- a little bit of idle screw adjustment, and a little bit of touching up of the tune at idle. Still not, "stock", but close... and hey, it doesn't stall and I can use the A/C again... so, altogether a win in my book.

Thanks again!

 

Im having the same problem as yours after installing the s1, and also did a flash...I'm going to try the biss adjustment see if it's solve the problem or not. Btw, mine is an ix