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My speedometer is crazy!

I’m the original owner of a '91 Nissan pickup (160k miles, 5-spd manual, 4 cylinder).

It’s been a great truck over the years, but lately my speedometer has been intermittently reading WAY over my speed. FREX, about double or triple what I’m actually doing.

The only factor that seems to make it occur pretty much every time is if I have to punch it hard from a stop and rapidly shift to 2nd gear. However, sometimes it just randomly chooses to read fast for no apparent reason.

Don’t know if it’s relevant, but the odomter works fine whether the speedo is being optiministic or not (I know my commute distance to the tenth).

All help appreciated…


Since the odometer is OK then I’m pretty sure it’s the speedo gauge itself.
You should be able to get an instrument cluster from the junkyard network.

If your truck has a tachometer, put markings for 30, 45, 60 mph in high gear and use that for your speedometer. If your truck doesn’t have a tachometer, I think there are tachometer kits that are easily installed. This way you don’t change your odometer reading by replacing the cluster.

Years ago, I used to ride buses owned by a small company. These were Flxible (yes, the spelling is correct) buses on GM chassis. I noticed that the tachometer served as the speedometer–it had differnent dials in different colors for miles per hour in a particular gear from 2nd through 5th. I don’t see why this system wouldn’t work for your truck.