Ideas of problem? Is the tachometer the problem if rev counter not working but dial showing engine hours still recording? Or something else the cause? Is there something I should check. Is on Cat 30 with universal engine. Needle showing revs just quit while engine was running. Thanks.
Tachometer quit working for revs but engine hours working
- Thread starter jefferies
- Start date
Jefferies, I think that tacho reads from the alternator output, I think. If the alternator is still making volts, then ya probably have a bad connection between the alternator and the tach. Yes, the tach also could have gone south, but more likely loose wire. The hourmeter still working says that the tach is probably getting voltage as it should when the key is "on"..
Last edited:
Does the engine still have the original crappy wiring harness with the trailer type plugs? These cause problems and are best eliminated. If the wire for the tach is not making good connection through one or both plugs, the tach won't work. As mentioned above, you know it's getting voltage as the hour meter part is working.
The plugs are only there to make installing the engine easier. Once it's in you don't need them. You can cut the plugs put and replace with proper heat shrink crimp connectors, or run them direct from the engine to panel if they are long enough. Best would be to replace with all new wires of proper gauge.
Last year I put a used Universal engine in my boat. It didn't come with the harness so I had to rewire from scratch. Not that hard to do.
Another possibility with an alt driven tach is that of the batteries are totally charged and nothing electrical is running, the alt cuts out and the tach stops working. If you turn on an electrical load, the tach comes back on. Unlikely to have nothing running though.
The plugs are only there to make installing the engine easier. Once it's in you don't need them. You can cut the plugs put and replace with proper heat shrink crimp connectors, or run them direct from the engine to panel if they are long enough. Best would be to replace with all new wires of proper gauge.
Last year I put a used Universal engine in my boat. It didn't come with the harness so I had to rewire from scratch. Not that hard to do.
Another possibility with an alt driven tach is that of the batteries are totally charged and nothing electrical is running, the alt cuts out and the tach stops working. If you turn on an electrical load, the tach comes back on. Unlikely to have nothing running though.