Egt

[Wing Nut OOA]

so the gauge i bought and installed for my 6.5 isnt working, (or so i think)

i unplugged the wires from the gauge and hooked them to a multi meter and measured the milivolts as i was driving.

at cruising speed it would read between 1 and 2 mv and depending on load sometimes would read -2 to -3 mv

i did get it up to about 7mv one time but this chart i found says that 400 degrees is about 8.5mv and my gauge doesn't start reading till 400.

i know i have to be running hotter than that.

do you think my sensor is bad? or is it the gauge? or am i looking at the wrong chart, maybe there are thermocouples that measure out differently than others?


millivolts to fahrenheit chart
(http://www.pyromation.com/downloads/data/emfk_f.pdf)

[rustyk]

Many EGT gauges require the manufacturer's own wires to work correctly.

[Wing Nut OOA]

It was a package deal, it all came with the gauge and sensor and wiring

[6.5 Detroit Diesel]

if it came with it's own standalone wiring, and that is all installed correctly, i would be checking the gauge itself. what did you get?

[Wing Nut OOA]

its a sport jdm universal,

Was 60 off ebay

[rustyk]

I got one off ebay - don't remember the brand - but it was crap. Rather than sell it to someone who might depend on it, I trashed it.

Ended up with a vdo, and had to buy a longer cable (about $70, IIRC) because my motorhome is a pusher.

[Artworks]

Did the gauge come with a relay " box"? I had some problems with mine as the box would get stray static and would be eratic. I had to make sure that all the wires going to the unit and from were not tangeled and separate from other wires. All connections tight and wrapped. I still have some problems with my trans temp acting up on ocassion ( but that is normal electrical with 6.5 GM !!!) I got my set up from Kennedy.

[Wing Nut OOA]

No relay box, the wires running to the thermocouple seem to have a heavy duty insulation and are inside a braided loom for added protection.

I guess I just have a crappy gauge...

My erratic millivolt readings are still puzzling though. Is it possible my thermocouple is bad? Can they go bad?

[JohnC]

My erratic millivolt readings are still puzzling though. Is it possible my thermocouple is bad? Can they go bad?
Yes, yes.

The insulation is so that the ambient temperature doesn't skew the reading. The voltage generated is proportional to the difference in temperature between the probe end and the gauge end.