> So I look over at the wb02 meter. Thumb on the pipe... idle A/F is now
> at 15.8. LEAN! HHmmmm. plug the pipe back on the valve cover...
> right back to, and dancing around 14.7-14.9 on the meter.
>
> Again... I ponder...So at high revs...I must be forcing even MORE air
> in past the carb piston so it must be running even leaner?
Paul, this is where you lost me. First, the fact it's running leaner with
the vent tube plugged, means that whatever was coming through the tube was
richer than 14.8. Not surprising when you figure that the purpose of this
system is to vent fumes that have been collected by the carbon in the
canister, and there should be no oxygen in the crankcase fumes
Second, why would you think the problem gets worse at high rpm ? The amount
of air flowing past the piston is obviously much larger, but since the
depression between the piston and the butterflies stays more or less the
same, the amount of air/fuel pulled through the emission system would also
remain the same. So, it would actually make up a much smaller percentage of
what the engine sucks.
IMO this was deliberate on the part of the original designers, to make the
mixture go lean at idle, thereby lowering idle CO.
> So here we go... I'm about to re-design the crank venting system.
> to work as it 'should' .
If you're going to do that, why not go whole hog, and design a true PCV
system with a fresh air intake, and an exhaust to intake manifold vacuum ?
BTW, is your A/F sensor the 'EGOR' that was discussed some years ago on the
DIY-EFI list ? If so, how do you like it? I've been wanting one of those
...
Randall
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