Bouncy tach gauge

[315neptune]

All of a sudden my tach gauge needle started moving all over the gauge. Any ideas as to what is causing this ?

[Route 66]

Welcome to iRV2!

Our members will be able to respond better if you post your;

Engine
Chassis
RV make and model

[TXiceman]

Until we get some more info you need to look for a loose wire or ground. Are any other electronics acting up?

And welcome to iRV2.

Ken

[315neptune]

isb cummins--roadmaster----2005 neptune---thank-you

[BZam]

Quote:

Originally Posted by 315neptune All of a sudden my tach gauge needle started moving all over the gauge. Any ideas as to what is causing this ?

I have 99 Freightliner with CAT engine.

My tach has a quirk. It goes to zero and back up ever so often. Sort with a graceful down and back up.

And I never feel any engine cutout.

I run VMSpc on laptop and have never logged a unusual event nor can I see this happen there.

So don't worry about it.

Probably something that would take a lot of chasing and money to figure out so just let it be.

Bob

[RustyJC]

I'm not sure if your vintage Cummins takes its engine speed signal from the crankshaft or camshaft position sensor, but a bouncing tach can indicate one of these sensors going bad or an intermittent connection between the sensor and the CANbus that drives the gauges.

Rusty

[Eaglesview]

I had an intermittent tach on an ISL. But as well the engine would momentarily stop and the diagnostic was 'loss of ignition".

Turned out to be improperly crimped wires in the engine ECM connetor.