Speedometer Adjustment for 5KTQ?

[Smeins, Larry]

Wallace,
If your speedo is off 5 mph at both 30 and 70, as was mine, changing the
resistor is the wrong fix.  The resistor is a slope adjustment and will make
a constant percentage correction.  The constant 5mph is an offset problem
and in my case was caused by incorrect positioning of the needle.  The
speedo doesn't start at zero but the needle is set very near the bottom
mark.  I rotated the needle down about 5 mph and got the whole range much
closer.  I broke one speedometer trying to remove the needle but was
successful in slipping the needle on its shaft on the second speedo.  A
small change in resistance can be done to fine tune the top end.  I've
promised a couple responders information on the resistor and when I get it
together I'll include you  in my mailing.  The original post was made by
paul.heneghan-at-bbc.co.uk in February 97.  A search of the archives may
find it.  Paul found more slope error and less offset error on his 89 100
than I found on my 87 5kcst.

Larry 

> -----Original Message-----
> From:	Wallace White [SMTP:wallace at stanfordalumni.org]
> Sent:	Monday, May 14, 2001 8:18 AM
> To:	Swann, Benjamin R. (BSWANN)
> Cc:	'Smeins, Larry'; 'quattro at audifans.com'
> Subject:	Re: Speedometer Adjustment for 5KTQ?
> 
> Ben -
> 
> My physical speedo also reads +5 mph. I've checked at 30 and at 70. The
> trip computer's speed is almost dead on, and the odometer is too. 
> 
> I would be interested to know which resistor to adjust... though I'm not
> going to pull the instrument cluster just for that.
> 
> Thanks,
> 
> - Wallace
>   '87 5kcstq 173k
> 
> "Swann, Benjamin R. (BSWANN)" wrote:
> > 
> > After comparing speedo with computer, 5 mph seems relatively consistant
> even
> > up to 60.  I haven't had a chance to check higher speeds, but it seems
> the
> > deviation is closer to 5 MPH rather than 10% I originally thought.  Yes
> it
> > has probably been doing this all along.
> > 
> > I dont know if I want to move the needle, as this would make the speedo
> > incorrect at low speeds, yes?  Also, I'm afraid of breaking it or making
> it
> > worse than it was. I can live with 5mph deviation at 60.  At least I
> know
> > how to correct for.
> > 
> > I wonder if the speedo reading inaccuracy correlates at all with the
> > odometer reading.  I'll do some more sampling on a long trip.
> > 
> > I would be interested in any other information regarding correcting the
> > reading, particularly with changing the resistor.
> > 
> > Thanks for all replies.
> > 
> > Ben
> > '87 5000cstqw