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Path: utzoo!linus!philabs!cmcl2!seismo!umcp-cs!chris
From: chris@umcp-cs.UUCP (Chris Torek)
Newsgroups: net.auto
Subject: Speedometer weirdness
Message-ID: <1402@umcp-cs.UUCP>
Date: Tue, 27-Aug-85 05:53:22 EDT
Article-I.D.: umcp-cs.1402
Posted: Tue Aug 27 05:53:22 1985
Date-Received: Thu, 29-Aug-85 20:35:14 EDT
Distribution: net
Organization: U of Maryland, Computer Science Dept., College Park, MD
Lines: 24

I was driving back from New Jersey early Monday morning, going
faster than usual (~55 [I have a Chevette]) when my speedometer
started acting up, as if the cable were sticky: the needle started
bouncing up and down around my actual speed.  Having seen this
happen before, I was unworried.  Anyway, it finally decided to
bounce all the way up to the stop, then all the way down to zero,
and settled on 30 MPH for a few minutes.  It eventually returned
to 55.

Well, it seems to be OK now except for one small problem: the needle
"sticks" at 30.  If I go 50 MPH, it goes up to 30, says there for
about one minute, then goes up the rest of the way and remains
accurate so long as I remain above 35 MPH or so.  When I stop, it
goes down to 30, sticks there for a few seconds, then plummets to
zero with a little "clink" noise as it hits the stop.

I am curious as to the mechanism involved here.  If the speedometer
were a simple ammeter, this wouldn't happen.  How do speedometers
work inside, and how might it have been damaged such that it sticks
at one particular speed?
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 4251)
UUCP:	seismo!umcp-cs!chris
CSNet:	chris@umcp-cs		ARPA:	chris@maryland