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Speedometer intermittantly goes crazy


Marck
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The other day, I was driving my sube and I look down at my speedometer and see that the needle is pegged at 130mph :eek:. Everyone else on the road was driving about the same speed, so I know I wasn't pushing more than 45mph.

 

What is the common problem or fix for when the speedometer reports 3 or 4 times the actual speed? The speedometer does this intermittantly and it works more often than not. When it acts crazy, you have to shut down the engine and restart and maybe if your lucky it will work like normal again.

 

My sube is a 87 EA82T Full Time 4WD sube. BTW, it has the analog cluster.

 

Thanks,

Mark

Edited by Marck
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My mom had a similar problem on her old Subey, she just laid a firm smack on the top of the dash with her hand, and it would start working correctly again, sometimes. Sometimes it took a couple smacks.

 

Thats good to know. I'll give it a try next time it happens, but I am looking for a permanent fix :rolleyes:.

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Aww, c'mon nipper!

Don't you have any sense of fun?

First time somebody drives your car and you hear "WTH?!?" when they hit

the street. :lol:

Oh god that was funny seeing that, whoo boy, sorry.

But yeah, nipper's right, you probably need a new speedo cable.

 

heheh well you want to expalin to him why he needs monthly oil changes :P

 

 

nipper

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Monthly? I only need to change mine every 2-3 months. :P

Plus I run high grade oil, and almost always keep my brat at 2k or higher.

Sure it may be a bit brutish, but considering the number of times people have

tried to run me over this winter I like to have a little power to get the hell outta

their way when their not paying any attention. :mad:

I've had too many close calls and few too many accidents. :mad:

And the majority of them weren't my fault.

 

Sorry rant over.

 

Twitch

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Monthly? I only need to change mine every 2-3 months. :P

Plus I run high grade oil, and almost always keep my brat at 2k or higher.

Sure it may be a bit brutish, but considering the number of times people have

tried to run me over this winter I like to have a little power to get the hell outta

their way when their not paying any attention. :mad:

I've had too many close calls and few too many accidents. :mad:

And the majority of them weren't my fault.

 

Sorry rant over.

 

Twitch

 

It was a joke.....

 

 

sheesh

 

if his spedo thinks its going 130mph, then its possible his odometer is reading the same thing (very very fast).

 

i'll go back to my dark corner now.

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Mine does that whenever it's really cold outside. Was it cold?

You may be able to get by with just re-greasing it. There was a post a while back about removing the end from the tranny and pulling out the inner cable. Clean it well, slap on some new grease, then slide it back in.

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I think its time for a new speedo. If it wasn't reading at all or reading low then maybe a cable, but pegged, that would indicate the hair spring has come loose or broke.

http://auto.howstuffworks.com/speedometer3.htm

 

It shouldn't mess up the oddom reading.

jm2c

Unc

 

The problem is intermittant and when it is broke, it doesn't read pegged all the time. The needle starts at zero @ 0 mph and increases at a rate that is about triple that of the actual speed. So when I get going at about 45mph or faster, the needle is pegged. An actual speed of 25 mph may show ~70 mph on the speedometer.

 

So does this sound like a speedo problem or a speed cable problem or is there a speed sensor too? Excuse my ignorance with how speedometers work and the parts of the system, but what does the speedometer cable look like and where would I find it on my car (I assume it connects to the tranny some wheres).

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Sounds to me like there's a bit of dried up goo in the friction bearing that makes the needle move.

 

These speedos (cable driven) use a friction bearing to translate the constant roundy-round of the cable into a one way movement of the needle, the faster the cable spins, the more friction is on the needle side of the bearing, and the higher it moves in it's range. If there's dried up lube in there, it obviously generates more friction at a lower cable speed, causing the needle to read higher.

 

This is most common on cold days, due to the lubricant being more viscous when it's cold.

 

If the cable is binding, it will either read a tad slower than normal or twitch the needle as the cable binds, builds spring pressure, and releases, which roughly translates into the speedo needle going down, waiting half a turn of the cable, and popping up.

 

This would translate into the above mentioned suggestion that maybe it's time for a new speedo... or a good thorough disassembly and re-lubrication of the friction bearing assy, if that's within your capabilities.

 

Hope this helps!!!

 

88RxTuner

Edited by 88RxTuner
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This is a common subaru failure. The seal in the transmission that keeps gear oil out of the cable has failed. The cable acts like a screw and sucks gear oil into the speedo head. The speedo, cable, and seal will all have to be replaced for an effective and lasting repair. Anything less will last only a short time or not work at all.

 

GD

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It doesn't do it when it is cold. It is pretty random. It started to do it again today in the afternoon, this time I paid attention to the odometer, it too looked like it is effected (looked like it was spinning faster than what it should have). I tried hitting the top of the cluster with my hand, but it made no change.

 

I think I'll pull the cable and inspect it first.

 

From what I understand:

If the cable has oil in it, then the cable and seal needs to be replaced. If the problem persists after replacing the cable assembly, then the speedo head needs to be replaced too.

 

If the cable doesn't have oil, then I need to relube it and reinsert. If problem persists, then I may need to repair or replace the speedometer head.

 

How hard is it to remove the cable?

Edited by Marck
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