Vehicle speed signal in Typ 89

[radek at istar.ca]

Hello fellow Audifans.

Thank you for your support.  So as I can see there are two possibilities:

1. a solder joint somewhere in the instrument cluster is bad;
2. the vehicle speed sensor is bad.

Option 1 is no big deal, it does not affect the car's operation. However, option 2 may
mean that
the ECU is getting wrong information.  So the big question here is:  does the speed sensor
supply
information to the ECU?  Put differently, are those high fuel consumption figures I get
while
the needle is oscillating true or false?

BTW, I took the speed sensor out of the transmission housing, cleaned the electrical
contacts (2-pin) and put it
back.  No difference.  Would anyone know how to test the sensor for output?
TIA

Radek
88 90Q
91 V8Q 5-sp.


> Message: 12
> Date: Thu, 13 Mar 2003 18:26:06 -0500
> From: Dave Hord <spokes at the-wire.com>
> To: "Brian O'" <briano_72 at yahoo.com>
> Cc: radek at istar.ca, quattro list <quattro at audifans.com>
> Subject: Re: Vehicle speed signal in Typ 89
>
> Hmmm...
>
> Good point Brian.
>
> There should be an easy way to check the speedo signal, but I'm not sure what
> that would be.  In my circle of friends we just pop a rally computer onto the
> signal lead, and know if it works instantly!
>
> -Dave
>
> --
> 86 4ksq 266,600km new to me as of March 5th 2003... will it stick around??
> 89 90q  330,000km as of Feb 26th.
> Rally Conversion...perpetually in progress...
> Roll cage shots available at:
> http://home.the-wire.com/~spokes/rollcage/page1.htm
>
>
> Quoting Brian O' <briano_72 at yahoo.com>:
>
> > --
> > [ Picked text/plain from multipart/alternative ]
> >
> > just get it over with now and get a new sensor, it should be just a little
> > more than hand tight, very easy to see and find, right on top of the trans,
> > kinda towards the drivers side, by the fire wall. the wifes old 90 80 speedo
> > was insane !! it bounced from 0-100, sometimes worked ( every time i was in
> > the car ?? ) sometimes didnt do anything. put the new one in, worked like a
> > charm !!
> >
> > brian o'
> > 93 90q sport
> > 93 100csq
> > 91 80 ( possibly sold )
> >
> >  radek at istar.ca wrote:
> > Hello fellow Audifans.
> >
> > This weird thing has been happening to my 88 90Q lately:
> >
> > from time to time, while driving, the speedometer needle starts to oscillate
> > (about 5 km/h
> > amplitude)
> > and the fuel consumption display goes crazy, showing consumption three times
> > higher than
> > normal.
> > There is no noticeable difference in how the car behaves. The problem comes
> > and goes
> > without
> > any pattern. Overall fuel consumption (mileage between tanks) seems normal.
> > No error
> > codes.
> > Is the vehicle speed signal screwed up somehow? How can I test it?
> >
> > I should add that the O2 sensor is nearly new, the temp. sensors (both, the
> > upper and the
> > lower) have been
> > replaced, but the car idles high (about 1000 - 1100 rpm.).
> >
> > I'll be grateful for any tips, this thing drives me crazy.
> >
> > Radek
> > 88 90Q
> > 91 V8Q