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spuggy spuggy is offline
Join Date: Jul 2003
Location: Glorious Pac NW
Posts: 3,534
Originally Posted by JFairman View Post
The stock lambda frequency valve on a stock unmodified aluminum USA lambda fuel head doesn't have any effect on control pressure like it appears your thinking.
It has no relation to control pressure at all.

The lambda frequency valve modulates lower chamber differential pressure in the fuel head to lower emissions and get better gas mileage when cruising and idleing. It does that by returning fuel to the return line going back to the gas tank.
Yes, the lambda frequency valve controls the lower chamber differential pressure, rather than the control pressure fed into the WUR.

But the Bosch K-Jet documentation states that the individual differential pressure valves on each fuel delivery outlet maintain the upper chamber pressures to within .1 bar of the lower chamber - so wouldn't it be true that modifying the lower chamber pressure directly modifies the upper chamber pressure as well?

As smurfbus is controlling the lambda valve with an AIC/1 and affecting his WOT AFR's, it would appear so...
'77 S with '78 930 power and a few other things.

Last edited by spuggy; 11-07-2010 at 05:48 PM.. Reason: fix quoting
Old 11-07-2010, 05:33 PM
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