1979 BJ40 B engine exhaust temp gauge help (1 Viewer)

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Joined
Jul 30, 2019
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Messages
201
Location
Orange County
Hey guys. My exhaust temp gauge has never worked. I would like to replace it. Any links on where to get the right one? Or what bolt thread size I need to find the right one?

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When you say it has never worked, what do you mean? No Power? Doesn't display correctly?
 
the needle never moves. So I figure it is no good? 🤷🏻‍♂️
Personally, I would do some problem solving/checking before replacing with a multimeter. If you just want to replace it, then it is probably easier to buy an EGT gauge and change the whole lot (they usually come with a new temp prob)
 
I would also first check what is wrong with that instrument......buut If you are going to buy a new one I can realy recomend the Auber Instruments 1813. I installed it maybe 1.5 years ago and I'm realy impressed by the accuracy and speed. I used it recently a couple of times to calibrate a mechanical water temp gauge. And that gauge is so slow compared to the auber that I' thinking of wiring in annother probe to the auber to get an reliable reading. The only drawback is that it comes as a rectangular unit with digital display. I realy like the normal 52mm gauges - especially for an classic vehicle like your 40. But this time the functionality and quality of the instrument has won my approval.
 
Personally, I would do some problem solving/checking before replacing with a multimeter. If you just want to replace it, then it is probably easier to buy an EGT gauge and change the whole lot (they usually come with a new temp prob)
So your question has me even more confused. Lol. This guage appears to come directly from the hole in the engine pictured, through the fire wall, and to my dash. No other power wires going to it. Should this guage be drawing power from another source? How does that hole in the engine create power to test with a multimeter?
 
Power could be for a light on that gauge. Usually the probes work, or they don't. If you don't get any reading it could be probe or gauge bad.

I would just unbolt the probe, then you will know what the thread is. Usually 1/8"npt is pretty standard. Choose whatever gauge you like. Usually the cheaper ones break quicker and less accurate. VDO, Autometer, IHI are good gauges if you want to go standard dial style.

I have a dual Auber gauge like @relaxedcruiser is talking about. Good gauges, fast and programable alarms warning lights. Auber also makes a round gauge, it's just not analog like most gauges. But that square digital looks fits in nicely in my 1988 BJ74.
 
Power could be for a light on that gauge. Usually the probes work, or they don't. If you don't get any reading it could be probe or gauge bad.

I would just unbolt the probe, then you will know what the thread is. Usually 1/8"npt is pretty standard. Choose whatever gauge you like. Usually the cheaper ones break quicker and less accurate. VDO, Autometer, IHI are good gauges if you want to go standard dial style.

I have a dual Auber gauge like @relaxedcruiser is talking about. Good gauges, fast and programable alarms warning lights. Auber also makes a round gauge, it's just not analog like most gauges. But that square digital looks fits in nicely in my 1988 BJ74.

The digital Auber guage would require an additional power source correct? Do they work with 24volt? May stick with analog for ease of replacement since I currently do not have power running to that guage.
 
The digital Auber guage would require an additional power source correct? Do they work with 24volt? May stick with analog for ease of replacement since I currently do not have power running to that guage.


Yes they do need power as they are digital LED screen. Just one power on with key and a ground is all the extra wiring, which is pretty much the same as every other gauge on the planet as they need power for lights.

24V version, then you just need an EGT probe which they sell as well.
Automobile Multimeter for EGT, Boost, 24VDC [SYL-1813-24] - $49.50 : Auber Instruments, Inc., Temperature control solutions for home and industry
 
FJ Ben - That's the one !

For some reason I believe that most EGT temp gauges are not mechanical and well require a power source. So if your gauge has not power feed to it this may well be the missing part to make it work. To check whether it is mechanical or electrical you simply check how the probe is attached at the back of the instrument. If it is a fixed, rather rigid connection which can't be disconnected, it is mechanical. If there is something like a normal electrical connection with a rather soft wire, it is electrical and NEEDS a aditional power source. A mechanical probe doesn't create electricity - there is a liquid in it and when this expands due to heat introduction it makes the needle in the instrument at the other end of that closed system moving.
Electric ones are available in 12 or 24 V.
I hope that you get it going the one or other way as it is a very insteresting and important instrument to read.
 
Pulled the old gauge and called the manufacturer. Hewitt industries here in California. The guy I talked to was very helpful. He said the gauge itself is mechanical. The back light is powered. Makes sense.

Got the proper kit ordered up complete with new gauge and probe.

Seemed to easy. And it was...

Pulled the original probe out and it took all the threads with it. Had to drill and tap new threads and buy an adapter to get the new probe in.

Thankfully my local auto part store had everything I needed. All went smoothly and now I know how hot my exhaust is.

No clue how those numbers help me but at least it works!!!!!

Thanks everyone for the help.

Now on to the next project. 🍻

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