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Hey guys, well here we go again lol. Ok so i started messing with the biss screw using the actuator to get my idle in line and made it worse. It was pretty damn good before but when you get the tuning bug you want to try and get everything perfect. Ok, so the car is an 04 with evo 9 turbo and full bolt ons including gsc s2 cams. Right now it idles ok but every once in a while it will start surging from target idle 953 rpms to about 1200 rpm. Also, when coming to a stop at a stop light or something it will hang at about 1100 - 1200 rpms for a bit. I turned the biss screw until i got the iscv demand trim ac off to 0 or really close according to a thread i read on here with alot of good info. Also, car has a bit of a warm start problem. I noticed when it surges the iscv position and demand spike. Also, seems to get worse some times when iat temps are high. Im in florida and its hot here. Ive tried messing with different tables but i think maybe i just dont understand the iscv tables enough. If one of you gurus could shed some light on the situation and guide me a bit so i can better understand the iscv tables it would be awesome. I will post a picture of the log right before i turned the car off. I will also post the log for the hell of it. This is the car fully warmed up.
* Note - If you play log back in real time you can see timing and afr fluctuate alot. They dont stay steady. I havent been able to control it. If someone knows how please chime in.
Last edited by nor11384; Jul 26, 2018 at 04:45 PM.
Hey guys, well here we go again lol. Ok so i started messing with the biss screw using the actuator to get my idle in line and made it worse. It was pretty damn good before but when you get the tuning bug you want to try and get everything perfect. Ok, so the car is an 04 with evo 9 turbo and full bolt ons including gsc s2 cams. Right now it idles ok but every once in a while it will start surging from target idle 953 rpms to about 1200 rpm. Also, when coming to a stop at a stop light or something it will hang at about 1100 - 1200 rpms for a bit. I turned the biss screw until i got the iscv demand trim ac off to 0 or really close according to a thread i read on here with alot of good info. Also, car has a bit of a warm start problem. I noticed when it surges the iscv position and demand spike. Also, seems to get worse some times when iat temps are high. Im in florida and its hot here. Ive tried messing with different tables but i think maybe i just dont understand the iscv tables enough. If one of you gurus could shed some light on the situation and guide me a bit so i can better understand the iscv tables it would be awesome. I will post a picture of the log right before i turned the car off. I will also post the log for the hell of it. This is the car fully warmed up.
* Note - If you play log back in real time you can see timing and afr fluctuate alot. They dont stay steady. I havent been able to control it. If someone knows how please chime in.
Linearize your Idle Steps - and Smoothen Ign timing in your Idle Areas.
If you search older threads there are so many threads that you can learn from but it will take some time.
You will have to do lots of logging.
Linearize your Idle Steps - and Smoothen Ign timing in your Idle Areas.
If you search older threads there are so many threads that you can learn from but it will take some time.
You will have to do lots of logging.
Basically this.
Drop the idle steps in the far right column of the idle stepper table. Smooth idle timing.
Here is a picture with more settings. Where would you smooth idle timing? I have the same timing all around the area where idle is
. Trust me, ive done hours of reading here but maybe im missing something.
Here is a picture with more settings. Where would you smooth idle timing? I have the same timing all around the area where idle is
. Trust me, ive done hours of reading here but maybe im missing something.
your running more timing at idle then I have ever seen suggested, at least for a stoich idle target. Im running a different setup but for my S2's i had them idling pretty happy @950 with this timing.
I thought there was no better way to smooth it out than make the numbers all the same where it would see idle. When smoothing out is it better to bring the numbers up gradually as if to help idle stability not have to compensate so much? If so how would i figure out where to take away or put in timing? I dont know if im making any sense, im bad at explaining my thoughts lol. This car for some reason doesnt like low timing at idle. It doesnt do well with the low engine speed lower timing puts out.
Well every setup is different, your the one sitting there tuning it so I can't tell you better what she likes and what she doesn't. Since its a hunting problem you have though you could try turning down the sensitivity in the idle stability timing control table. I have mine set at 122 / 8 / 8
So the more sensitivity the more prone to hunting? I tried turning down the timing to 8* and the desired rpm up to 1000. When starting it would struggle to find idle. I can probably fix that with maf comp or post starting iscv but it did the hunting thing. Also just didn’t feel right. Maybe because I’ve always used higher timing at idle idk. Can you explain what you consider “smoothing” at idle? Setting all the values the same isn’t enough?
So the more sensitivity the more prone to hunting? I tried turning down the timing to 8* and the desired rpm up to 1000. When starting it would struggle to find idle. I can probably fix that with maf comp or post starting iscv but it did the hunting thing. Also just didn’t feel right. Maybe because I’ve always used higher timing at idle idk. Can you explain what you consider “smoothing” at idle? Setting all the values the same isn’t enough?
Yah the more sensitive the more likely it is to take large swings when its oscillating. When you did that change did you wipe out your learned trims? If not you should probably try that and let it idle for a good 20 minutes or so, when it would normally start learning fuel trims and see how it settles out. If it stalls go back and add more timing, otherwise let it do its thing.
Actually now that you mention that, I disconnected battery so it would reset trims but with my normal timing. When it started it idles pretty decent for a while but after like 5 minutes it started the slight hum again. I guess when it starts learning trims it does it. I can’t try it with lower timing and see.
Actually now that you mention that, I disconnected battery so it would reset trims but with my normal timing. When it started it idles pretty decent for a while but after like 5 minutes it started the slight hum again. I guess when it starts learning trims it does it. I can’t try it with lower timing and see.
I prefer idling my S2s in open loop. May be a richer idle than 14.7 .
Idle is not that straight forward, Also if you have low z 1000 cc + injectors you will run into minimum IPW
which will cause trouble making it idle. Stock injectors wont be an issue.
Try to match your IDLE RPM Value with your Idle steps and BISS.
Yah idle is tough because if you tweak one thing you usually have to go in and change other things. As far as setting the biss give the method I described a try. With the engine running warm adjust the biss until the logged steps match what you have set in your initial position table.
Jul 26, 2018, 12:28 PM
