Odometer not working but speedometer works

[jamlen]

This is my first time on the forum as a relative new Porsche 911 owner, and I'm impressed with how much knowledge is shared on the forums. I have a 1985 Carrera (84,800 miles) with 5-speed manual transmission. Today I noticed that my odometer no longer works but my speedometer still works fine. Will replacing the speedometer cable fix the odometer problem? Or do I have a bigger problem than just a cable? I have never worked on the Porsche but I've done routine maintenance on Mazda RX-7, Volvos and Saabs. I'm willing to give this a try - all I have is a Haynes Manual!
Thanks for any help you can give.

Jamlen

[EarlyPorsche]

Send it to speedometer.com

[Hugh R]

No cable, its electric. Common problem. You can fix yourself, but I've heard its not worth the $125. North Hollywood Speedometer will fix, repaint the face and calibrate. Don't let the shipping to Southern California bother you. Post a pic of your car if you want to get more help. Its sort of a rule around here. Welcome to the board.

[scottbooth]

In your 85, the speedometer and odometer are both electronic, so instead of a traditional mechanical drive cable, you have a magnetic sensor on the transmission that detects the speed of the drive axle. The speedometer uses this signal to indicate speed and to rotate the odometer.

The odometer drive gear is a common failure point, and the failure mode is what you are seeing - speed indication still works but odometer stops counting. Your options are to replace the gear yourself, have the speedometer repaired, or replace it with a new one.

I think Pelican sells the replacement gear, and there is a tech article on how to do the fix. But to take the speedo apart you have to uncrimp and pry off the black metal bezel on the front, which is hard to do without damaging it.

Common rebuild options (besides the one EarlyPorsche mentioned) are North Hollywood Speedometer (www.nhspeedometer.com) or Palo Alto Speedometer (www.paspeedo.com). Any local gauge shops that work on VDO units should be able to fix it also.

Good luck
Scott

[JeffreyNMemphis]

Did you reset the odomoter while the cars was moving? This is a common way that they break.

[75blkcarrera]

Had the same problem! North Hollywood Speedometer did a wonderful job. Considering having the rest of the gauges done also.

[Formerly Steve Wilkinson]

Don't listen to the people who say you have to post a picture of your car. I've posted one of mine in six years, and only under duress. We all know what 911s look like.

[brendon]

I fixed mine myself. I got the gear from odometergears.com, if I recall correctly. Not sure if our host is carrying them or not (they weren't when I did mine)

[84porsche]

It happens. All you really need is the tach anyway if that. Drive by sound. . I have been with a broken odometer for almost 3 years now but since I already had 180k before, I don't think a few more miles with hurt the value much.

[rnln]

if you post your pic, we will come and sing "happy birthday" in front of your house.

[cpgaylor]

guys
i have a 86 carrera, 115K miles, my speedometer jumps all over intermittantly but the odometer works fine. cruise control is real screwy jumps up and down. any ideas where to start?
thanks

[Gogar]

cpgaylor, it's probably a good idea to start a fresh thread about your problem. More people will see it. Or try the famous "search" button.

[rick-l]

Start a new topic.....but

Is your alternator ok? does your seat belt light come on for no reason?

Originally posted by cpgaylor
guys
i have a 86 carrera, 115K miles, my speedometer jumps all over intermittantly but the odometer works fine. cruise control is real screwy jumps up and down. any ideas where to start?
thanks

[cpgaylor]

everyhthing else works, just the speedometer is jumping around and the cruise is erratic, (to put it mildly)