Running lean for no reason

[YZFR1]

Started doing this today and it's driving me nuts

I have been raising boost slowly on the 14b from spring pressure, got up to 14psi and everything felt and looked great. Than today, raised boost again up to 15.5 psi and logged almost 34 lbs/min with AFR's in the mid-low 11's, then on the next pull going down the same road it started running very lean, around mid-low 13's AFR and knocking while at it. It did this twice (first pull fine then the second one is not) and each time the car felt and drove fine afterwards so it's not like any particular injector gave up or anything.

The next thing i'm going to try doing is dropping boost back to 14 psi and logging my injector duty cycles, however, i really doubt that i'm maxing them out. My fuel system right now is a supra fuel pump, upgraded fuel lines, Denso HI 550's, 93 Octane and an oem fpr (have an aftermarket one, just not sure if i need it yet).

Looking for some input as to why it would run fine on the first pull but not the following, twice? The only things i can think of is sticking injectors or an oem fpr but people have made over 400hp with it.

Thank you

 

[WES_393]

Just by seeing 34 lbs/min from a 14b, I'd bet your MAF needs a serious calibration. I would start by following this link. maftcalibrationbywbo2 [ECMTuning - wiki]

 

[YZFR1]

To tell you the truth, i'm not exactly sure of how accurate the maf reading is, i don't really have to calibrate it the same way as you would in link. However, i really don't think it has anything to do with my original post.

 

[lil corb]

Looks like you are on the stock 1G MAF which would put you in the ball park of over running your maf.

maffrequencylimits [ECMTuning - wiki]

It happened to me, the MAF would start spiking different HTZ causing a really lean condition. Upgraded to a EVO Maf now.

 

[YZFR1]

Sorry, i should've mentioned that i'm running a 2g MAF. But nonetheless, why would it work on the first pull and not the second? And do that twice

I was just looking for some suggestions, i'm sure i will figure it out eventually, it just sucks running lean on a new engine

Thanks for all the feedback!



EDIT:

Meditated some more on this issue last night.

When i got this new shell i upgraded the 3" FMIC on it for a stock side mount. Since, that only gets me that much closer to my dream of running a hotpipe.

Is it possible that my SSMIC get heat soaked enough after the first pull that on the consecutive pull i'm a whole 2 AFR points off? I figured this might happen eventually just not that quick

 

[Dert]

Did you allow a bit of a cool down between pulls? If you did it back to back the later pull will draw in hotter air than earlier pulls. Allow plenty of cool down time between pulls.