EGT Gauge Basic Questions

[steelheadguy]

When I bought my truck used it had an EGT probe and gauge already installed but not working. I could see the wires dangling, not connected to the round needle gauge.

I tried connecting the wires and still the gauge does not move. Before I do anymore troubleshooting, I figured I would ask a couple questions so I can understand how they work.

1. From what I see there is no 12 volt power to this. Just two wires from the probe to the gauge. Does this sound right? Does it function with just the heat and no electric power?

2. Are the two wires at the gauge interchangeable? Or does polarity matter here?

3. Are there any tests I can do with a multimeter to test the gauge, probe, and wiring?

Thanks guys. I searched and found plenty of EGT info but not these very basic questions.

 

[crash-harris]

2 wires is normal (passive). Just means that the gauge measures probe temperature against gauge temperature. The wires aren't interchangeable.

 

[steelheadguy]

Also, the distance from the probe to gauge is only about 4 feet. Whoever installed it left an extra 2 feet of wire coiled up. Will this extra unnecessary length of wire affect how it functions?

 

[crash-harris]

Doesn't affect it. Btw, don't use crimp connectors or solder on the wiring. The wires are made of different material and once cut can basically only be twisted back together, unless you use a special solder. I can't recall all the details, but I'm sure someone else will chime in on that.

 

[steelheadguy]

I crimped two ring terminals on. Im guessing thats my problem?

How should I connect the wires to the posts on the gauge?

 

[ReticulateSplines]

I have a gauge that I purchased myself, and installed using manufacturer instructions. I recollect something about not cutting the wires between the probe and gauge but that is where I will stop.

I would find out who made that gauge and either download the instructions or call their customer service. If neither of those are options available, it probably isnt worth running that gauge.

 

[Macrobb]

An EGT probe is usually a K-type thermocouple. Anything that applies to k-type thermocouples applies to EGT probes. https://en.wikipedia.org/wiki/Thermocouple
They generate their own electricity, in very tiny amounts.