Low o2 values at WOT (tired fuel pump?)

[cathan]

Hey all,

I am seeing dangerously low O2 numbers on the Scanmaster at WOT, (750, and even 600's!) sometimes decreasing as I watch .

I have tried to compensate by turning up the fuel pressure, does not seem to help.

The fuel pump is a very old walbro 307, maybe not even strong enough for this newer motor (see sig) when it is new.

I understand the fuel sock can become clogged, and very likely is, but do these pumps also get "tired" or weak before they go kaput?

Any opinions on an appropriate pump are also appreciated.

Perhaps it could be a problem with the O2 sensor itself? But less likely as it was replaced with the new motor a few years ago.

Thanks,

Chris

 

[SCOOBY DOO]

It's time for a new fuel pump...and stick a fuel pressure gauge under the wiper arm to ensure the fuel pressure is rising with boost.

 

[cathan]

Yes, I have a fuel pressure gauge under the wiper which I also have been watching....

Any opinion on which is a good pump for this combo?

Racetronix?

Armstrong?