TR2/3/3A tr3 gas gauge

[sp53]

I know this is a well traveled path, but I need to be retrained everyday almost. Anyways, I bid on that fuel gauge and sending unit on eBay and missed it. I was hoping it would solve dilemma. My problem is I put an untested and fiddled with fuel gauge and sender in my 61 tr3 and the needle does not register correctly. It probably has 5 gallons in it and registers just above empty. I think Geo suggested to take a hanger and hook the sender and lift it up to see the gauge move and I will try that today and see what happens. I also read that article from a MGA owner and his ideas about the gauge and how it works. I guess my questions is has anybody on the forum successfully calibrated a gauge by moving those little hair thin wires that are attached to those little studs. I have to admit that I cleaned this gauge before I put in the car and could have easily done damage.
Steve

 

[NutmegCT]

Steve - I don't recall messing with any hair thing wires, but I calibrated my gauge with no problem. Now reads very reliably.

I followed the instructions at:

https://mgaguru.com/mgtech/electric/fg_06.htm

Hope this helps.
Tom

 

[dklawson]

Many LBCs used that type of gauge prior to the mid-1960s. I have re-calibrated three such (non-TR) gauges following the MGA Guru site information. It does work. If you attempt calibration outside of the car (which I did), make sure all the components housings' are connected to the electrical earth of your power supply. The gauge and sender will not work properly if they do not have a good ground.

 

[TR3driver]

Also check your sender resistance. As I recall, the TR3 sender is slightly different than the MGA.

 

[sp53]

That article is very helpful. The one I read was different. I will reread the article a few times and give it try. Thanks all so much, perhaps it was serendipitous that I did not win that bid.
Steve

 

[martx-5]

Also check your sender resistance. As I recall, the TR3 sender is slightly different than the MGA.

Yes, I just went through all of this on my car. The MG article uses 0-70 ohm resistance. The TR's use 0-90 ohms resistance...all this give or take a few ohms at each end. I used 47 ohm resistors for calibration, (in series and parallel) and they worked out fine.