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Re: Re : fuel questions
> The membrane valve controls system pressure, in the absence of a control
> valve in the metering head. In place of the metering head valve, there's
> a disc on a rod that seems to isolate the right-most port of the three
> from the other two. I think fuel is free to flow between the middle
> and left port.
Perhaps the built in valve wouldn't work at the pressure they wanted, so thedy
used an external valve to control system pressure.
> > >From the wiring diagram, valve N is a "Taktventil fuer Lambdaregelung" - a
> > frequency valve for lambda control. Odd - because there is no lambda sensor
> > anywhere on the car, and no catalyser. It runs on leaded petrol.
> > Yup, Lambda freq valve. When an O2 sensor is present, this valve is used to tweek
> > the fuel mixture(by varying the fuel pressure, not sure which one?) to maintain
> > the stoichiometric ratio 14.7:1. Maybe you recall some posts about people
> > setting the CO using the 3mm allen (Hex) wrench in the hole between the air meter
> > and fuel dist. When the O2 is present, you can connect a DVM up to a test connector
> > , 2 pin near the ign dist, and watch the duty cycle of this freq valve. Here we set it to
> > 42% or close. I run mine at 32% to richen it up under high boost.
Yep, just like the MC in my 5k.
> I don't have any O2 circuits. The only adjustment provided for is the
> standard CO adjustment. I don't see any way to change a "duty cycle".
> At what frequency is the valve driven? Mine seems to buzz at 10Hz to
10 to 15Hz would be about right.
On the MC, the frequency (lambda) valve is used for more than just fine
tuning the mixture - as soon as you get on boost or at WOT, the system
goes open loop and ignores the O2 sensor, providing fuel enrichment.
It actually runs at a fixed frequency, it is the duty cycle that matters.
A greater duty cycle enrichens the mixture and I set mine around 40%
It sounds to me like your (Phil's) car is using a K-Lambda system that
runs open loop all the time - no O2 sensor, hence I'll bet a 50%
duty cycle at idle.