As usual I have not correctly stated my problem. The following Q & A should
clarify my problem.
> What are you trying to do with the addition vacuum?
Well... The PI system sets the mixture based on the manifold vacuum. At best
the system is only approximate since it is an open loop controller. Since I
have exhaust gas oxygen sensors I was going to build a circuit that adjusts
the vacuum in the metering unit so that the fuel to air mixture is correct.
The circuit consists of a solenoid vacuum valve that is driven at a fixed
frequency where the duty cycle is adjusted to provide the correct vacuum to
the metering unit. Mechanically the metering system will be set rich and
electronically I will lean it out to the correct mixture. Another option is
to provide pressure to the back side of the vacuum diaphragm, however, this
may interfere with the normal operation of the metering unit and will only
be used as a last resort.
Yes this does sound like a lot of work for a little bit of gain, however,
there are much bigger plans IF I demonstrate that this will work ;)
Thanks to all who responded (and more thanks to those who don't flame me)
Lee Janssen
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