Control Pressure Question -- Higher equals Richer or Higher equals Leaner?

[dduclaux]

Does higher control pressure (WUR pressure) richen the A/F mixture or lean the A/F mixture?

Riddle me this: why do we increase the control pressure via the vacuum port on the WUR on acceleration?

[stlrj]

Higher control pressure leans the mixture. The vacuum on the WUR actually reduces the control pressure for increased throttle response when the throttle opens and the vacuum drops off.

Cheers,

Joe