Troubleshooting Genny Temp Gage

[Alaskan Sea-Duction]

OK TF experts need help troubleshooting my genny temp gage.

Basic info: Onan 8 MDKD-3CR/2650B, Ser# 1870947950

It would also appear the engine part of the genny is a Kubota. The manual isn't much help in troubleshooting the gage.

The temp gage is located in the control box on the genny. The control box is a rats nest as far as wires etc. If needed I will take it apart to get the gage out. So here is the question:

How do you troubleshoot to find out if it is the gage or the sending unit?

Thank you in advance!

 

[AusCan]

Is it not working at all, or just not accurate?
Check for power to the gauge. Some operate at reduced voltage (around 5 volts). So it is possible the transformer could also be the problem.

Check your sender by measuring the resistance across the terminals (or terminal to body). Resistance should decrease as temperature increases. Different models vary, but normally when cold the sensor should be a few thousand ohms, and about 200 ohms when hot.

If possible - get the manufacturer (VDO?) details off your gauge & sender and look up the specs on them.

 

[Alaskan Sea-Duction]

Not working at all. The hour meter is bad too. The oil pressure and volt meter do work.

 

[caltexflanc]

I could very well be wrong, but one of the first things I'd do is short out the sender with the genset running and see if the gauge jumps. If it is an electric rather than mechanical gauge of course. If mechanical I'd guess it is almost certainly the sender, but would replace the feed tube to make sure.

 

[catalinajack]

I could very well be wrong, but one of the first things I'd do is short out the sender with the genset running and see if the gauge jumps. If it is an electric rather than mechanical gauge of course. If mechanical I'd guess it is almost certainly the sender, but would replace the feed tube to make sure.

Even if you were able to get a reading on your old guage, its accuracy would be quite suspect. If it were I, I would replace with a new guage and matching sender. I replaced all of the guages on our Defever 44 (upper and lower) stations with digital units from Intellitronix. Are they accurate? I think so, at least the temp guages. Why do I think so? I recently replaced the thermostats on my Lehman 120's with thermostats purchased from American Diesel. They are 195 degrees, the recommended temp by AD. At 1,600 RPM the guages consistently read 195 degrees, plus or minus a few from time to time.