Re: Weird CIS behaviour

["Fred Munro" <munrof@isys.ca>]

Hi Phil;

    I ran into this same problem on my '86 5ktq. The new check valve gave up
the ghost after one month's use and exhibited the intermittent leak-down
behaviour you are describing. Replacing it solved the problem.

HTH
Fred Munro
'91 200q  248k km
-----Original Message-----
From: Phil Payne <quk@isham-research.demon.co.uk>
Date: Sunday, March 22, 1998 12:22 PM
Subject: Weird CIS behaviour


>I've been having a hot-start problem intermittently for a few months.  I
>thought that replacing the check valve in the fuel pump had cured it, but
it
>happened again last week.
>
>So I decided on a comprehensive day on the fuel injection.  I'd noticed
several
>times that the residual pressure falls too quickly when the engine is
turned
>off, so I decided to put the gauge on and start swapping bits.  Swapping
out
>the frequency valve cured the slow leakdown, so I was fairly happy.
>
>But something odd happened when I was running the diagnostics.  On two
>occasions, fuel pressure fell like a rock when I turned the ignition off.
All
>the way to zero in five to six seconds.  Turning the diagnostic back on,
>waiting the usual four seconds, and then turning it off gave me the
approved
>behaviour - pressure retention above 2.8 bar for over an hour.
>
>Has anyone ever seen 'intermittent leakdown' before?  Any ideas?
>
>--
> Phil Payne
> UK Audi [ur-]quattro Owners Club
>