NPS300 speed sensor fail

[nikpo]

Hi,
Carried a new sensor with me as I had a speed sensor fault reading. Speedo starting fluctuating after 1000 km. Next morning the speedo was dead. Can only get 2100 rpm.
Changed out the sensor, traced the wires in the loom to see if there might be a broken wire, and checked the the drive on the gearbox wasn't broken.
Still no luck.
Any suggestions?

 

[SkiFreak]

Is your truck still under warranty?

 

[nikpo]

Amazing..hours and $ later, the problem was that the spigot that the sensor is fitted to on the gearbox has "4" positions. The spigot is actually tapered on one side. If this is fitted incorrectly then it chews up any sensor that one fits. What's also incredible is that the original sensor worked at all. Some clown obviously took out the spigot, replaced it incorrectly...but it stilled worked. The correct position has "13" stamped into the spigot

 

[SkiFreak]

Only goes to show that even in the technologically advanced world we live in now, idiots are still allowed to design mechanical equipment.
Glad you solved the problem, but if it was designed well, you would not have had a problem to solve!

 

[Aussie Iron]

Yes, (the spigot) it sits in one of four positions depending on the number of teeth that the gear needs for your speedo to give the right reading. And also it does have the position marked on the top by the number of teeth. Should say this is on a Canter so seems to be the same on an Isuzu.

Dan