Monaco tach bouncing

[Art Ward]

What cause the tach on my diesel pusher to bounce around? How do i fix it? Art

[jimkate]

You don't say model and year, although I assume it is a Monaco product. On mine, when the tach starts jumping around, it's likely because my alternator is failing. The tach gets its pulse signal from the alternator. But, it's different on different coaches. On some newer electronic models, the pulse signal is provided by the engine ECU.

Jim Sanderson
Canada, eh?

[Art Ward]

Thank you!
It is a 2007 Monaco and i've several electrical issues with this coach. This last time the tach has started bouncing around. I hadn't looked at it yet, Didn't really know where to start, I was going to try to trace where the wires from the tach went to and go from there.
The tach is annalog so I probably need to look into the alternator first. Again, Thank You for the information. Art

[txrumbleweed]

hmmm mine does that too... pretty grimy back there... wonder if cleaning the contacts would help....

[Eaglesview]

Possible cause would be intermittent power or ground to the Engine ECU. We had poorly crimped connectors to the ECU on a new 05 Dynasty. Tach very twitchy during factory delivery. After 1,000 miles engine would momentarily quite, then start at low power for a minute or so and then resume normal operation. Finally laid down five miles south of Medford, OR. Towed into Medford Cummins, damage to both mirrors and back on the road in a couple of hours. Been fine since.

Lots of other electrical issues with coach when new. Fine now at 65,000 miles.

[Art Ward]

I have an 06 Monaco "Cayman" pusher.
I have it at Mcclain's RV in Mckinney right now, Thursday they called said it looked like corrosion issue. They were going to get back to me.
I've had good service from McClain's so far, had it there for camera issues and some small stuff. But they change service managers a lot. anyone had any experience with McClains in Mckinney? Art

[hamguy]

Quote:

Originally Posted by jimkate The tach gets its pulse signal from the alternator. But, it's different on different coaches. On some newer electronic models, the pulse signal is provided by the engine ECU. Jim Sanderson Canada, eh?

What is the pulse signal? And how can an alternator provide any information about the engine speed? Just wondering.