I had the fuel issue. All of us with issues have the problem in more than just 1 location and they are all almost the same spots: around 1800, 2500, and 3000

In all honesty I would like to see the a/f at that area to see if it's rich stumble or lean stumble. I doubt it's plugs because you do'nt get spark blow out during vacuum.

If the a/f is going lean when it stumbles i would have the tuner just start adding fuel in that area as best as they can. Also make sure the o2 corrections are off when tuning the vac map. Not much else we can help with here on the internet except advice to tell the tuner.

hope it gets cleared up.

 

Ya, they have already put tones of fuel into the spots @ 2500rpm.

Its still 18+ lean, just goes to --- on my AEM wideband.

 

strange. i guess it wouldn't hurt to try fuel dampers to see if that helps.

 

I got to thinking... Since this problem with the Hesitation after Quickly shifting gears only presents itself wheN I am either quickly shifting gears, or if I take my foot off the gas, then put it back on quickly... Could this be from my BOV (TiAL Sport 50mm "Q" blow-off valve) not having the correct spring in it? Or from not Closing quick enough?
So it creates a buffeting effect.

If I Granny Shift and Slowly build up boost then it doesnt present itself lol. Only When I Quick shift or go into vacuum (On my boost gauge) then back on the throttle.

 

I just read http://www.tialmedia.com/documents/BOVspc.png

Says
"If you have a quick spooling turbo it can actually push it open.... leaking boost..."


hopfully this is it haha.

 

unplumb your BOV. 2 second test will tell you if thats the problem. HIghly doubtful though

 

You can adjust your transient throttle settings if you had a haltech

that way when you are between shifts and coming back into boost it can add some fuel. I don't think osiris can do this though so again, not sure what to do.

Question though if boost is pushing the BOV open wouldn't it reduce the amount of air going through the throttle body (and thus the engine) therefore making it rich? IE, you would have quick boost leak which would cause more fuel than air temporarily.

 

MAF is after the BOV. So it would just adjust accordingly wouldnt it?

 

What bugs me is I can't find anywhere that says how to setup flat foot shifting on the old haltech? Not really that important... car's not coming together for another month or so lol.

I'm pretty sure we can all agree, it's probably not the BOV. Although having a maf is going to cause problems.
Fuel resonance issue... And that's it. I don't think there's much anyone can do with that. I'm not sure what causes it, and these guys all have had experience with the best shops around on tuning so there's not much else to say on the topic. Maybe playing with the fuel system can shift it around etc... but beyond that I imagine your car either has it or doesn't.

 

there is no flat foot shifting in the haltech, thats why you cant find it.

 

I was hoping someone had a clever setting for aux limiter (in trade of traditional two step), so the ignition cut was quick or smooth or something...
I'd rather have flat foot shifting than two step... Can't really afford axles, slicks, or anything else that will benefit from a two step launch. (especially driver mod, driver's got derpez ).
Fck it though. Wot box is mah onleh hope

 

Haha Actually I have a Brand new, Never installed still in box, WOT box that I bought a year ago for my S4.... Make me an offer and its yours haha.

 

the root of the problem is overcompensation (both fuel and timing retard) during spoolup. Post up the timing logs while this is happening if you can.

I had a similar issue that was clearly evident in logs, timing dipped sometimes even negative on hard upshifts or rapid throttle changes which felt just like misfire. Long story short, it is 99% fixed by retuning. The uprev tuned ECU looks first to the MAF table to make timing/fueling decisions so it's critical you get the tune as close to perfect as possible via MAF then make only small changes (if any) to the fueling tables. My fuel table is actually all 100's at this point, and the MAF table looks absolutely nothing like the Uprev supplied table. If you have any fuel compensation cells +/- 5% or large sweeping changes in either timing or fueling tables it's a big problem. Quicker spoolup is always going to make the problem worse... my GT25R's were very difficult to get just right and took a good amount of street/track tuning to iron out hesitation before it ever hit the dyno. On the dyno we were able to get rid of the last bit of the 'shift gremlin' (which was very occasional by this time) by leaning out the spoolup areas of the tune and adding some cam advance. That said, a no lift module might help but that's really just a band aide. Remember, we're asking it (uprev tuned ECU) to do something with only a MAF reference that it was ever intended for. It takes experience, time and some creativity to nail down an F/I tune just right without a MAP reference. And it won't ever be perfect.

 

What do you want me to monitor when I log? Give me a list...

 

ign. advance
throttle position #1 (v)
accelerator position #1 (v)
rpm (engine speed?)
a/f both banks
fuel schedule (ms)
cam advance both banks
MAF (v)

anything else you want to add is fine.

 

Here's an example of a tune related timing issue on an upshift that feels like noticable hesitation. Dark green line.

 

that's interesting. So you're saying timing drops to zero on shifts djamps? In that log it looks like timing advances fully between shifts. Between shifts my timing advances and usually goes really high since the car drops down to the vac portion of the map. I'd like to know this so i can optimize mine. I don't really have an issue but i just like to learn as much as i can about tuning.

flat foot shifting on the haltech can be done with the aux limiter attached to the very top clutch switch (the one that cuts the cruise). Hal did it this way so as soon as you depress the clutch it limits RPMS via aux rev limiter. Have it set to cut spark and that is exactly the same thing a flat foot shifter does.

 

No it goes up during shifts like you would expect. But once you engage the next gear after it overcompensates and the timing becomes unstable. Notice the rough patch after I engage 3rd gear. The timing was dropping to 10-12 and fluctuating until it comes back up to 15-16. In some cases it is much worse, with timing dipping as low as 5, 0 or less for a about a second. Even during the shift you can see some instability...

 

what did you do to fix that timing swing?

 

oic, ya mine has never dipped that far before. Shifting hard into boost for me usually puts it back in the low to mid-teens which is what my map has in that area so no worries. Maybe it's a think with osiris?


this i would like to know in case i encounter it on someone else's car.