Avant died and reborn again...

Phil Rose pjrose at frontiernet.net
Sat Mar 6 19:59:23 EST 2004

At 1:27 PM -0800 3/6/04, Bernie Benz wrote:
>Phil, I'm not sure that I buy your suggested reason for stall after sudden
>throttle closure under boost with a failed closed BPV.  The throttle plate
>is a pressure balanced valve, i.e. equal plate area on either side of the
>throttle shaft center line, thus it's position is unaffected by differing
>pressure drops across the valve.  More likely IMO, just that the ECU is not
>programmed to control idle in a timely manner, while the ISV is still
>subject to boost pressure.

You suggest that the stall is a "lean-out" situation caused by 
excessive (boost-derived) air being passed through the ISV? You could 
be right; I was just stating what I thought I'd read to be the 
"official" reasoning. I'll accept your explanation unless someone has 
evidence or better reasoning to the contrary.

>If this throttle body had a throttle air bypass
>adjustment aka the 7A, this problem could be adjusted out.

What is  that?



Phil Rose
Rochester, NY
mailto:pjrose at frontiernet.net

More information about the 200q20v mailing list