New Fitech install, stuttering issue
Once last question before I get into the IAC step adjustment: Do they need to be adjusted while the car is at 170? All the reading i do doesn't really seem to make mention if this is a requirement or not.
You mention exhaust leak: Sometimes i'll hear a slight 'pop pop pop' that seems to be in time with the rpms... coming somewhere behind me. Could that be the exhaust sensor bracket slightly leaking, and if so, could that contribute to this? Note, it hear it very infrequently, but it does happen. I should note the exhaust itself is brand new done by a pretty reputable shop around here.
Thanks!
Went ahead to warm it to 170, the adjusted the IAC. Got it pegged right at 5 during idle now: 1/4 clockwise turn of the screw.
Did a 30 second log during idle: I don't use dropbox, but here is a shareable google drive link:
https://drive.google.com/file/d/1j6Cni36GYeg-qBuR8r9cHHq9gt5SyOAC/view?usp=sharing
Let me know if that's not viewable. I'll be taking it for a drive later and will log it with the stutter.
Log looks good. Your vacuum is in range for Cam setting 1.
Turn key to on, go to initial settings, select cam selection, enter 1, send to ecu, turn key off, let ecu power down. You probably know this. Turn key on and verify change was saved.
Start engine, warm over 170, check IAC steps.
As exhuast leak. Where is your O2 sensor mounted. Should be approximately 1 foot from header collector. An exhaust leak from about 18 in past the sensor and all exhuast system up stream from sensor will cause problems.
Does it stumble at steady throttle or only when applying throttle?
Here is a combined log of the car at idle, then a few block drive (all at 170+). I was able to reproduce the stutter at idle while revving it, and while driving. Since I turned the logger off/on (one for the idle, and one for the drive), it looks like it put a blank row in the spreadsheet to symbolize this?
https://drive.google.com/file/d/1Fa-DDX_ibkEJEPLR9wxtsZNaDKDMg9iK/view?usp=sharing
After lunch, the return trip, which is from a idle to driving around, this time with my wife driving it so I could look at the handheld. Numbers do chance on the handheld during the stutter (like one would expect), but I'm not sure which is the cause and which is the effect. I also did your cam update before the drive home: It was 1 before, and 1 after.
https://drive.google.com/file/d/1YiiCXTcRp-3CQxVpgjgrIh0wi9KtR0zk/view?usp=sharing
IAC seems to look good while idling now.
I checked: They mounted the exhaust sensor just about 1' away from the left side header meets up (I have dual out exhaust, no crossover), so that seems to spec. In my head I thought it may be further back, simply because when I hear that 'tick tick tick' it seems like it's behind me, not in front where this actually is. But it could be the audio waves bouncing around weird, or something entirely different.
To answer your last question : If I push hard on the gas from idle, the car moves, no stutter. But if I don't want to give everyone whiplash and do a smooth pull-away, it does the stutter. And it stutters intermittently when up-shifting between shifting gears.
So, I loaded some of that into a google spreadsheet (I normalized the values so they are viewable on the same page for comparison). I compared rpm, fuel, and vacuum, and got the below chart. This was just me pushing on the gas during idle and getting the stutter. Again, I don't know what is cause\effect, but it appears the fuel is clearly cutting out (I called that out with my red draw-over), then quickly bounces back.
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Monitor your AFR when it stutters. Probably going rich or lean when you ease into the throttle. This is an Accel issue. You can increase or decrease the Accel on its own menu in the Pro Tuning section. I wouldn't mess with the Fast Accel settings yet...
Your last Logs were below 170 degrees. I do see an AFR issue when you crack the throttle, but not consistent .
Great, I'll look there next, thanks.
You're right about the coolant temp on the first log... that's really weird, I intentionally waited for it to warm up past 170 on the handheld.
Tonight I messed around with the accel pump stuff a lot. Definitely waited for it to hit 170 then started. This is what I found:
Going 10% at a time, I didn't really notice much of a difference until I hit 80-90%. Even then, I could still make it stutter, about 3 times in 10. Sometimes subtle, sometimes the normal drastic cutout. Seems to be happening less though? Can't tell if it's just the placebo effect. However, I was just giving it little bumps of gas from idle.
Then I really stepped on it: It started stuttering at a much higher RPM (which I'd never noticed before, usually there is no stutter at all if I get on the gas): It's like by increasing the normal accel values, it pushed the issue into the fast accel. So I started bumping the fast accel values up, but it was behaving really weird accelerating hard with the normal accel set to 99.
Ultimately I set both normal and fast accel to 50%. It's... better... maybe? I can definitely still make it stutter though.... but I think less?
I'll try driving it into work tomorrow with these values and see how it behaves. I'd appreciate your thoughts though.
I had recorded a log for this, but it appears to not have saved for some reason. I thought I gave it ample time to download to the handheld... any tips I should know about that?
What is your base timing set at? And total timing....