If you have a VAFC-2, tune at WOT and have been having hesitation problems when accelerating, I hope your Low and High Throttle settings are 39% and 90%.

According to FSM, Open Loop engages at 40% throttle and 3000 rpm. Now, we know the VAFC-2 cant tune below that because the ECU takes control of the AFR in closed loop using the main O2 sensors. This is why I chose 39% for Low Throttle instead of the suggested 10%. I don't want my VAFC interfering with the ECU's capability of managing itself stoichiometrically.

I made the mistake of setting my throttle settings to 39% low and 40% high. This means, at 41% I was trimming 100% Throttle worth's of FUEL. No wonder my car seemed to lag after 3k. I didn't go around flooring WOT everywhere, I just enjoy spirited driving, gradually pressing on the gas for a nice smooth acceleration. So I was constantly at ~50% throttle taking away 100% throttle worth's of fuel.



Anyways, I read this thread a while back and stopped half way until tonight. I finished reading it completely and realized streetlegendz had it right. He made perfect sense and all credit goes to him.
http://forums.maxima.org/all-motor/3...g-advance.html

So if your running a VAFC2 with a High Throttle setting below 90%, here's your answer. Let the VAFC-2 do its job and interpolate! That's one of its neat features.

If you didn't have low throttle settings or don't have a VAFC...then looks like you've got some Coil/MAF troubleshooting to do.

 

I dont have any hesitation problems but i'll give his thread a read. I have some tuning to do myself...

 

Same here.

I'll check my settings anyway. Thanks for the Info.

Edit: That thread has some really good info in it.

 

Good info here too.

http://forums.maxima.org/4045406-post8.html

 

That makes sence. All this time I didnt know what open and closed loop was until I read these links.

 

I was under the impression that open look was just above 3k. I didnt know it was above 3k and 40% throttle

 

yeah, one or the other gets you open loop

Btw, this worked for me for about a week, the hesitation is back...

 

what settings you using?

 

39-90,

 

I switched mine to 30-95 after realizing at 39-90, and ~+40% throttle, its only taking away about .5% fuel. Not really enough...

30-95 seemed to stretch it out a bit.

You eliminate any other possibilities like coil packs/MAF?

 

no matter what I try, it comes back, but not always. It seems the VAFC can't compensate and interpolate fast enough in some situations.