Chances are on a '94 it's still mechanical, and a couple things are going
The 'clockspring' is going away (but not that likely)
The cable is biting the dust. This makes more sense, since it is affected
by the brakes. Maybe the cable's binding on something.
If it's electronic, then I would look for a loose connector or a bad
The speedometer cable is the more likely suspect, can be
disassembled easily for inspection, and is a whole lot cheaper to
replace than the speedometer head. When it starts going bad it snags
and when it 'unwinds' it makes the speed indication bounce up.
Take the cable loose from the transmission and the back of the
speedometer head. With both ends loose, a good speedometer cable core
should spin easily with finger pressure. If it jerks and fights, or
sticks, it's bad.
The core pulls out in one direction or the other, there's one end
with a thrust flange on the drive tang or square drive adapter, and
one that's sized to fit through. If the core is tight and intact the
entire length, clean it off and grease it with a white lithium grease
or a motorcycle cable lubricant and put it back.
If it's sprung and frayed, replace the core and the casing as a unit
- the inside of the casing gets damaged by the sprung core, and it
will damage a new core. And if it's sprung badly the core won't pull
out easily (or at all), if you do get it out it will never go back in.
Treat the new cable and core gently, you can kink and ruin them by
installing it roughly and bending it tighter than the allowed limits.
--<< Bruce >>--
I could be wrong, but speedometer cables in Toyotas generally make noise
before they start causing erratic readings, and the complaints I've seen
generally are a needle that wobbles, not one that reads 0 and then too high.
Anyhow, a cable is a less expensive fix so it wouldn't hurt to fiddle with
The speedometer head is located in the instrument cluster - it is driven by
the speedometer drive cable from the transmission and includes the head,
gauge, and needle. To change it, remove the instrument cluster, disconnect
the cable, unscrew the speedo head, and reverse the process. You need to
attach a label in a conspicuous place to note the correct mileage when the
old one was removed.
Whether the car will pass smog depends on the laws where you live. I doubt
if a speedometer reading is necessary to pass a smog inspection but it
probably will not pass a safety inspection if there is one in your state.
And, DON'T use WD-40. I would say PB Blaster, but I have found something
even better than that. GM Penetrant and Lubricant. Comes in an aerosol can
and runs $8~12 at your local GM parts counter. Superior stuff!
After driving with the needle pegged for a while, the speedo head starts
bouncing all over the place. This was a problem when the max indicated
speed was 85 MPH ;-)
I doubt if this is the cause of the OP's problem, but the result is the
On Mon, 9 Jul 2007 20:37:13 -0500, "Ray O"
<rokigawaATtristarassociatesDOTcom> wrote:>After driving with the needle pegged for a while, the speedo head starts
No - "pegged for a while" on a mechanical speedometer system
indicates something mechanically wrong in the speedo head, the
reluctor cup is making physical contact with the spinning magnet
(driven by the cable) to toss it to full scale.
Or it's got a big glob of grease or other high-friction gack in that
gap that's effectively doing the same thing - dead bugs? Spider eggs?
But reading 0 (stopping) for a while and then going way high before
settling down and reading right (at least for a few seconds), with the
odometer dials doing the same thing, that would be a speedo cable
binding and jamming (and slipping somewhere at the transmission drive
gear end most likely) and then freeing up and zinging the needle high
as it unwinds.
That's always a good clue - if the speedometer reads crazy (0 MPH or
9999 MPH) but the odometer is still ticking up miles like normal, the
cable is turning like normal. THEN it's in the head, gaaa-ron-teed.
If they aren't listening for odd noises, they could easily miss it.
I'll hear an odd noise (sometimes rather loud) in a car or a piece
of equipment and know what it means, point it out to the owner of said
equipment, and they'll invariably say "Gee! I never noticed..."
Lots of mechanical and electronic things in this world will give you
a whole lot of advance notice that they have problems /before/ they
break - if you know how to listen to what they're saying. ;-)
You can call me "The Car Whisperer." (Among other things.) ;-P
--<< Bruce >>--
The speed indicator has no direct connection to the driver on a mechanical
speedometer. There is a magnet connected to the driver that rotates around
a drum like receiver connected to the indicator. If the needle jumps it in
generally caused by a cable in need of lubrication or a worn cable or
housing that is causing binding.
"Ray O" <rokigawaATtristarassociatesDOTcom> wrote in message
Gee, the driver just looks at it. I never had a direct connection to my
speedometer when I was the driver. In fact, I would have to take apart
the dash to just touch it. ;-)
> There is a magnet connected to the driver that rotates around
Here is the latest scoop.
Sometimes it works fine when I start my car and drive for a few miles.
Other times after I start the car it just always stays at 0 mph. Some
people have been saying to lube the cable. However, I don't know
exactly where it's at. Please let me know so that I can try it out.
Thank to everyone for your help.
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