Thread: Mechanical Speedo help

The good news: With 0 additional mods, I have gotten my classic to run from a stop to an indicated 60mph in 3 seconds!! The bad news is that my speedo starts out at 25mph. That is, while the car is turned off and not moving, the speedo rests at 25mph. The needle still moves, at highway cruising speeds my speedo indicates around 100mph. And it has gotten a bit worse. It used to only be off by 15mph, then I was passing somebody and when I got back to cruising speed it was 25mph off. I have a '91 classic with the mechanical speedo.
It started doing this about 2 weeks ago when I was having grounding issues with my car and I thought I messed something up when I was fiddling with the starter. But I never messed with the cable. Also, my tranny had been leaking for a few weeks, but still had a lot of fluid in it when we drained it.
So the speedo still moves fine, it is just always 25 mph too high. Any suggestions on where I can look for the problem?

Damn... I can hear my echo in this thread... Anyone?

Could the gauge itself be effed?

I'm curious of what the speedo does if you disconnect it from the tranny - just remove it and then re-install it. I wonder if there is a kink in the cable, or if it is tweaked down there. If you were working on the starter, you could have put pressure on the cable somehow.

The SE-R speedo is probably the same as all B13's (just guessing). You could grab a spare from the junkyard.

Josh

If the gauge reads 25mph when the car is off the problem is most deffinently with the gauge.

The stock tach's/speedo's are very susceptible to failure anyways, and i often doubt their accuracy.

The speedo assembly up to the back of the cluster is in my opinion either working correctly or not working at all. I just cannot think of a feasible situation where it would cause it to be "off", it spins or it doesn't, agree?

However the gauge, is much more mechanically delicate and while it might be working partially, it is most likely "tweaked".

Gl

Dudeman

I'd say it's the cable.I just replaced the one on my nx not too long ago.

Yes, the speedo is still sweeping, it is just sweeping from the wrong starting point. I read in other threads that people have taken the needle off the cluster and then put it back at the proper point (removing it and then put it back so it is pointing at zero while the car is stopped). Would that fix it? Also, I forgot to mention that my odometer is still working properly, I don't know if that helps narrow the problem down.