Re : fuel questions

[Phil@sievers.com (Phil Payne)]

In message <s34a7411.000@EWICO1.DIGITALGLOBE.COM> Dave Lawson writes:

> The closest thing I can relate to is the 1989 MC engine I installed in my ur-q.
> MC - 2.2l, hyd head, single knock sensor, ECU controlled wastegate, K26
> turbo, MAC-11B/C ECU, etc, etc.

Close.  One extra knock sensor and a MAC-12.

> The system is standard CIS K-Jetronic - up to a point.  There is no vacuum
> connection to the control pressure regulator (a.k.a. warm-up regulator), and no
> pressure control valve in the metering head itself.
> >
>
> Correct, my old CPR has the vac ports and the later one doesn't.

What about the system pressure control valve?  Was yours in the metering
head or separate?

> No idea what the membrane valve is. Valve N sounds like the O2 frequency valve.

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.

> >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.

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
15Hz.

--
 Phil Payne

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