16+psi, OE GT25 and OEM fuel pump- Anyone running this combination? Or similar?

[Preferio]

Under WOT between 3.3k and 4.2k I have a 'misfire'. If I ease into it, it's nowhere as bad. And sometimes almost non-existent. My AFRs go lean each time indicating it's not an ignition problem, but a fueling problem. I am running 16psi, maintaining it, with a spike to 19psi and up to 21psi before turning my MBC back. Even when exceeding 16psi (which is all the AFC has the ability to tune to, my AFRs were still no higher than 12.4s which is a result of a rich OE tune possibly.) All my mods are listed below. I believe the OEM fuel pump with 186k miles is the culprit and just can't supply enough fuel. It was proposed in another thread that the cause was is my tune. While I can understand it as a possibility, I doubt it because this started happening a month or so after the tune. My question is this:

Who of you are running higher boost applications on an OE pump?

Any and all help is appreciated.


I have data-logged runs that I can post once I'm home later tonight or tomorrow.

 

[shane02pro5]

Many have run 300whp on the stock pump but that doesn't mean it's not the problem... I'd say your at the limit with no timing being pulled!!

I started seeing knock on my J&S at 13psi with a larger turbo (IHI VF22) in that midrange area which is also when the vics valves in the im trigger. The J&S set up for the protg can pull timing in that midrange area and feed it back since this is typically where its necessary. Does the afc have throttle pump settings to add fuel at different rpm ranges upon a "throttle romp"?

 

[Preferio]

No, it does not.

 

[bobbyboneback]

what is your over pressure set at bro sounds to me like its not changing over to open loop smoothly I had that problem when I was running the t25 if you set your overpressure to -1.5 and adj the map from -23hg--0hg that's where the lean and or rich problem is the car is not changing over smoothly and it seems like it is a miss but it isn't its just that when the car changes over to open loop what ever you have it put at will show up like say you have 11 in the hg it will seem to be rich and if the overpressure is at 1 and the map has a 6 there it will be lean just as rule of thumb 10 is no change. and anything above is rich anything below is leaning it out. I would start there as far as hiccup that your having I bet is right where the overpressure is set at +/- 1

 

[hornsfan10609]

Damn, that makes perfect sense I can feel when the AFC kicks in sometimes in my car. Good call bobbyboneback

 

[KrayzieFox]

Damn, that makes perfect sense I can feel when the AFC kicks in sometimes in my car. Good call bobbyboneback

That's VTEC...

 

[Preferio]

It was cracked ceramic on #3 of the brand new plugs...