sr running lean during boost..

Hey there, I’m pretty new to sr’s as this is my first s13 with one. I have an AEM wideband and during idle and cruising along it’s between around 14.3 and 15.5, but when I step on it And hit boost it runs anywhere up to 17.7.

I have a HKS EVC III boost controller, but it’s currently off because I’ve yet to figure out how to use it and I don’t want to go around and just change numbers. So the car is just running stock boost.

Any help?

S13 I assume…

Fuel pump and wiring…hardwire a Walbro 255 with some decent gauge.

Sorry, yes it’s an S13 with an S14 blacktop. It currently has a walbro 255.

So does anybody else have any ideas? I’m also running a Megan turbo manifold and elbow, fmic, and a 3" exhaust.

Thanks!

FPR could be bad and not letting the fuel pressure build along with boost pressure…?

Try what Dan said about hard wiring the fuel pump (running your own, new lines to the pump). Your pump may be getting a shitty power source?

Sorry I’m so out of the loop, but FPR? I’ve never wired up anything major really so I’ll have to look into that perhaps.

Fuel press regulator