Recently I had my engine rebuilt, installed a new 16psi pulley on the sos charger, and had a retune on Kpro.

All was running perfectly, and the only thing I've done on Kpro was add a new map sensor when I got home from the tuner. (sos 3 bar) Everything still sounds great, and after some review I've come to a few conclusions for the fuel cut. But I'm not entirely sure where to start troubleshooting, and hoping someone could help me out.

Whats happening:
+20 C day (70-80F)
cars warm with 3 bars (and 30 to 40 minutes of drive time after warm)
Vtec engagement is around 4100 i believe (hard to feel that kick in, but fairly certain its working)
wideband will flip from 12.6 to 15.6 at highway cruise speeds (120 km/h, or 70mph)

That's my diagnostics that I can think of. Car seems to be running great, til you punch it. hits 7500 rpm (2nd gear) and fuel cut out on me. Tried 3 more times 2 pulls in 3rd and another in 2nd. Anyone had a related problem after uploading tuners info to your lap top to adjust? (it wasn't locked out by tuner) The tuner also mentioned that my fuel pump (walboro 255) was nearly maxed at high rpm. So I have a 320 in the mail but I find it hard to believe the pump would lose only top end feed rate.

Any suggestions?

What I've checked:
Plugs looked fine but I replaced them anyways.
Dropped and sifted oil, no metal bits or anything, still fairly gold. Replaced with new 10w30 mobil super for new engines and new filter.
Engine has roughly 2500km on it. (3 oil changes now)

Need more info, just let me know? I'm a little puzzled!

Thanks, Chad

 

I had an inline Earl's fuel filter in my old GST. When it would get dirty and obstruct the flow of fuel, it would feel like hitting a wall when hitting full boost. It would drive perfectly fine under all other circumstances. What I'm getting at is if your tuner told you your Walbro was running out of steam, I believe you've found your issue. The pump probably just isn't able to provide enough fuel for your engine's demands. Either that or there's something off with your tune.

 

Yep sounds like fuel pressured drop

 

appreciate the opinions guys, I guess all will be told once the new fuel pump arrives.