83 944 that runs and drives fine. But the speedo and tach don't work at all. MPG gauge works fine however. What should I be looking for?

 

Speedo is mechanical on your car so its most likely the speedometer cable.

Remove the drivers front tire
at the center of the brake hub youll see a cap and at its center a small circlip...

There is a good chance that if its broken the cap, circlip still intact, and the end of the cable will come off in your hands once the tires off.....

remove circlip.....then cap.....
give cable a tug and the metal core will slide out if the cable is broken.

I just did this job on my car 84na a couple of days ago...Youll likely have to pull the steering wheel and ignition/wiper/signal assembly to get the dash cluster out.....but its really not a hard repair....snaking the new cable through the firewall is a bit of a challenge....youll likely want to use fishtape, string, etc when you pull the old....to make a guide for the new.

My odometer is still dead....I started to open the assembly but found the gauge ring removal a bit more hassle then I had patience for....I dont like uncrimping anything 27 years old that I dont have a replacement for onhand.

As for your tach.....Mine worked fine so Id rather not offer unqualified advise beyond "clean your grounds".

 

Thanks for the tip about the speedo. I'll check that out. As far as the tach, I've cleaned all the grounds that I could find! Do these tachs often break or is it more of an electrical problem?

 

clearly what you should do is buy the white and black speedo cluster that i have for sale...

https://rennlist.com/forums/924-931-...ml#post8358327

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regarding the speedo, also look behind the gauges themselves, the speedo cable is somewhat difficult to attach in limited space (short of popping out the tach entirely and sticking your hand into the darkness) and someone may have just given up..lol

 

Just checked the speedo cable from behind the cluster and it's definitely screwed in all the way. I'll have to check the tire fo that cable.


Any ideas about the tach? Connections behind the tach are clean and are not corroded.