frequency valve, 200tq '89 MC2

[Ameer Antar]

what is cavitation? and would clogged stuff or system pressure cause a lean 
mixture or rich mixture that goes out of the OXS system range? Usually low 
pressure reduces fuel in EFI, but I have a feeling in CIS, it might be 
different b/c fuel pressure is used to actually 'set' the mixture. Just 
trying to relate this to a problem where my '84 5kT has an over-rich 
mixture at idle, but pretty normal mixture above that. I had thought maybe 
the connectors for the idle and WOT switches might have been swapped, but I 
don't think it's possible...Thanks.

-ameer


At 05:21 AM 1/24/2001 , you wrote:
> > This is a multi-part message in MIME format.
>
>It shouldn't be.  Somehow got past my MIME message filter.
>
> > Checking the car I noticed that FV buzzes not constantly but =
> > periodically (on idle), with 1-2 seconds breaks when it is silent.  On =
> > my 200tq '89 MC1 it buzzes constantly. Is it normal on MC2 (MAC-14)?  At =
> > output test FV  sounds ok.
>
>No, it's not normal.  I suspect it's running all the time and struggling
>with cavitation _most_ of the time - the quiet periods are when it's
>not having trouble.  You'd need to attach a fuel pressure gauge to the
>system pressure to be sure.  First suggestion is to check the fuel pump
>screen and remove it if it's clogged with brown stuff.
>
>--
>  Phil Payne
>  http://www.isham-research.freeserve.co.uk/quattro
>  Phone +44 7785 302803   Fax: +44 7785 309674