Re: [xj-s] Bad Speedo

["Frank O'Malley" <frank@hpato.aus.hp.com>]

Matt Dillon wrote:

> 
> .....I've had problems with the transducer that mounts to the
> transmission. It basically takes the mechanical turning of  the transmission
> and changes it to an electrical signal to run the speedometer. I've had
> several in the car and they've all lasted anywhere from a year to a month.
> Sometimes they just die solid, sometimes they work intermittently. 
> 

Hi Matt, Scott, and all,

I have had problems with my speedo transducer also, ever since I
bought my '83 XJ-S HE last November.

I had the speedo transducer replaced back in April, and the new
unit seemed to operate normally for only a few days. After those
few days, the speedo intermittently dropped down to zero, and at
one stage it dropped to zero without budging for a whole week.

Whenever the speedo dropped to zero, the cruise control would
also "drop out," if engaged. (The odometer and trip-meter both
stop rolling over as well.) This led me to assume that the
speedometer and odometer were in fact OK, and that the
speedo transducer had died again.

In fact I was about to write to this list asking for help. But
one Saturday about 6 weeks ago I unplugged the big edge-connector
on the ECU in the boot (to try to fix an erratic idle problem)
and I cleaned the contacts with a spray contact cleaner. Since
then the speedo hasn't missed a beat!

I don't understand why cleaning the ECU connector would improve
the reliability of the speedo, as the speedo doesn't appear to
connect to the ECU (according to the schematics in my XJ-S Repair
Operations Manual with HE Supplement).

However, I am sure now that the speedo in my XJ-S is now 100%
reliable.

Can anyone shed some light on why this might be? Is this a
well-known problem with the speedo transducer? Does the
speedo/cruise control take some sort of feed from the ECU?

Scott and Matt: perhaps you could try what I tried, and see
if your speedo becomes rock-solid-functional like mine has.

Cheers,
Frank O'Malley
'83 XJ-S HE

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