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Bouncing Speedo Needle

Posted: Thu Oct 23, 2003 9:10 pm
by mikec
Hey Everyone! This just started happening this week, and became more pronounced today, which is why I'm posting. The closest previous thread I could find was this one: http://www.bbs.legacycentral.org/viewtopic.php?t=2079

Anyhoo, I first noticed that my speedo needle would bounce when I was cruising at about 110 km/h. Along with this, I noticed the cruise control was having a hard time maintaining a constant speed (could feel the car accelerating and decelerating). Today I noticed it doing the same thing, but then it started bouncing whenever I was moving, regardless of whether I was holding a constant speed or not. Didn't try the cruise control at all (too much traffic).

I'm somewhat concerned because it was doing it over the entire range of speeds I tried. But at the same time, after a couple of red lights, it was as smooth as when I first started driving the car. Any suggestions on what I might check? TIA!

Posted: Thu Oct 23, 2003 9:19 pm
by HomeSlice
check your speedo cable on the tranny and cluster side. may just wiggled loose over the years. then again it could be the cluster itself

Posted: Thu Oct 23, 2003 9:55 pm
by evolutionmovement
Burrying the needle tends to cause this... :wink:

Though not in this car, it was my old GL's with the Joan Claybrook 85 mph speedometer. The cars could hit the 'P' in 'MPH' in top gear. Strangely enough, the same top speed as my ex's Monte Carlo SS due to gearing.

Steve

Posted: Thu Oct 23, 2003 11:32 pm
by mikec
I haven't even come close to burying the needle yet!

Just got back from dropping my sister off - bounced on the way there, no bouncing at all on the way back. This makes me both :? and :x

I'll double check the connections at both ends and let you guys know what I find.

Thanks again for the help!

Posted: Fri Oct 24, 2003 2:47 am
by totech
hahaha.

And you were laughing at mine as it bounced constantly....

Oh well, I have just got used to it..

My other car does not bounce :lol:

Posted: Fri Oct 24, 2003 3:42 am
by mikec
totech wrote:hahaha.

And you were laughing at mine as it bounced constantly....

Oh well, I have just got used to it..

My other car does not bounce :lol:
So it was you! I knew someone was to blame for this happening suddenly! :)

Wacky Speedo

Posted: Sat Oct 25, 2003 3:31 am
by G-reg
In the winter, ND USA, my speedo will rock and roll when the car is cold. It bounces, and sometimes will out accelerate the actual speed. I found my self going 110mph in second gear a few times :twisted: I poked and prodded the connectors I could get at, @ the speedo and into the tranny. I've swapped in a new/used tranny this summer, so I'll see if that helped it's behavior.

I FOUND THE FIX

Posted: Thu Nov 20, 2003 3:31 pm
by snowjob
Hi I'm the guy who's post you qouted. I had the same problem of the bouncing needle. Well After replacing the speedo cable, and various other things, I thought I'd check the speed sensor on the right side of the tranny, held in by one bolt. When I unbolted it, and had a look it was covered in goop, a silver sludge(hopefully my tranny isn't eating itself to death) Anyway cleaned it off, reinstalled it, and voila no more bouncing needle. My boost has even increased and my engine is no longer hesitating. Easiest fix I've ever done. Give your Sensor a clean and see what happens. It only took me 10 min to do.

If you have any questions give me a shout

snowjob

Posted: Thu Nov 20, 2003 4:13 pm
by mikec
Where exactly is the sensor located? Its not underneath the speedo cable, is it?

Posted: Thu Nov 20, 2003 7:23 pm
by vrg3
Strictly speaking, the part that attaches to the transmission is the "driven gear" and the sensor is in the gauge cluster... But a gummed-up driven gear definitely will mess with readings.

Posted: Thu Nov 20, 2003 8:07 pm
by mikec
I was hoping that's what we were talking about, because I couldn't see anything else.

The upside is I discovered my tranny grounding cable is gone. Totally and utterly gone. I can see the ring terminal still attached to the tranny, but don't see the actual wire anywhere. But that's for another thread.

Posted: Fri Nov 21, 2003 12:45 am
by Legacy777
Yeah the driven gear can get sort of icky.

Mike, where's the grounding strap for the tranny?

Posted: Fri Nov 21, 2003 12:57 am
by mikec
Josh,

All I see is the end of a ring terminal sticking straight up from the top bolt that holds the tranny together (near the speedo cable hole). There's a bit of corroded wire, but that's it. No wire that I can see otherwise.

I was starting to doubt whether there was supposed to be something there until I checked my brother's Impreza, and saw he had one. He's bringing a digital camera over tomorrow evening, I'll see if I can grab a pic before the end of the weekend.

Actually, while that's on people's minds, how would I go about repairing it? I saw a post here that questioned the necessity of it, but I'd like to repair it if possible. Would undoing that bolt be asking for trouble? I'd hate to think the 2 halves of the case are held together by 1 bolt.

And to keep this on topic, I'll be sure to check out the driven gear when I get a chance. :wink:

Posted: Fri Nov 21, 2003 1:00 am
by Legacy777
just put a ring terminal on a wire and run it to a ground point on the chassis.

Posted: Fri Nov 21, 2003 1:03 am
by mikec
So undoing that bolt won't cause any trouble? With everything that's going on with this car right now (the broken PCV tube, the constant coolant smell from the engine bay), I'm worried even looking at it wrong will cause it to erupt in a ball of flame. :(

Posted: Fri Nov 21, 2003 3:53 pm
by Legacy777
I'm not exactly sure which bolt it is......but I wouldn't think unbolting the bolt to put another ring terminal on would cause it to fall apart.

I need to go find the bolt you're talking about to be sure though.

Posted: Mon Nov 24, 2003 5:28 pm
by mikec
Image

The pic is kinda bad, now that I look at it. Sorry!

Posted: Tue Nov 25, 2003 12:43 am
by Legacy777
what side of the tranny is that on, what general area?

Posted: Tue Nov 25, 2003 12:46 am
by Brat4by4
That looks like it is just a nut. You'll have to really soak it in PB Blaster or something. Nothing should come out when you take it off.

Posted: Tue Nov 25, 2003 12:51 am
by Legacy777
see the connector that's on the bolt....looks sorta green.

That's what he's talking about.

Posted: Tue Nov 25, 2003 1:01 am
by mikec
As long as removing that bolt isn't going to be a problem (didn't think it would, but figured it was safer to ask), I'll pull it off and stick a new ring terminal on it. I've really gotta start some kinda grounding cleanup on this thing!

Thanks for the input guys!

Josh, that nut and bolt are right on top. They sit just behind the plane of the firewall.

Posted: Tue Nov 25, 2003 4:14 pm
by Legacy777
hmm....I'll try and look for it on mine.