Missing the Buz -or- My Fuel Distributor is too quite andmy car runs like

David Head v8q at bellsouth.net
Wed Aug 14 13:39:21 EDT 2002

Not true - the frequency valve (duty cycle) will go to preset settings in the open
loop mode (low temp, O2 sensor open/shorted, WOT switch actuated)  - but it is
operated from the ECU/fuel pump relay and is always on when the car is running.

Ameer Antar wrote:

> Turbo motors use a frequency valve which buzzes along to regulate the
> mixture. It sits sorta near the fuel filter. If the system is in open-loop
> mode, it shouldn't buzz. Maybe the system can't get into closed-loop mode.
> A bad o2 sensor, or any other sensor might cause this. I'd test the
> resistance of the valve itself to make sure there's no short or break in
> the windings too. Is the duty cycle showing up on the freq. valve's signal
> wires? If the signal is there, the valve might not be responding any more.
> Of course, you should check for vac leaks and clean or replace any aging
> parts for the entire system. Good luck.
> -ameer
> At 12:12 PM 8/14/2002, you wrote:
> >Subject: Missing the Buz -or- My Fuel Distributor is too quite and my car
> >runs like
> >  crap
> >To: quattro at audifans.com
> >From: robert_a_dupree at bankone.com
> >Date: Wed, 14 Aug 2002 10:18:24 -0500
> >
> >This I am sure is related the other message dealing with the missing
> >Engine-Speed-Sensor code that it being observed but...
> >
> >I need someone to refresh my memory on how the duty cycle function works on
> >CIS.  Or rather what are the critical inputs to re-enable the duty cycle
> >function.  The buzz is gone, and even when using the basic quick check of
> >moving the fuel flap up or down (while running) I don't get the buzz.
> >
> >As soon as I find the fuel pressure tester I will check control and system,
> >but what other sensors, components, or functions are required for fuel duty
> >cycle?
> >
> >Rob D.
> >
> >
> >
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