Sending Unit is toast ......

[George Zeck]

Hi All -

I've been away for awhile. All better now. A little drive and finally had the car with a near empty gas tank and dropped the tank to examine the sending unit. It's gone. Here's my problem (self-induced, of course). In my haste to update things - I added a ebay fuel gauge (Smith's p/n: BF2300 / 02) to my 1964 AH Sprite MKII. Now I need a sender which doesn't (perfectly???) match the car & is reading incorrectly or not at all.

Could anyone confirm that this was out of a 1965 MGB? I re-read some very old posts and someone stating such. Assuming it is, I just need to see if the sending unit for MGB would fit in my car (1964 AH Sprike MKII). Otherwise, I might be in for a new gauge (re-build?) to "match" all items up together.

Any other idea's are welcome.

Tx-

George J. Zeck
Cleveland, OH

 

[dklawson]

The link below confirms that the part number you listed is for an early MGB.
https://www.thegaugeshop.com/shop/a...GAUGE-BF2300_02.html?shop_param=cid=5&aid=78&

The early gauges work without a voltage stabilizer. The sending units that work with them operate in the opposite direction to those used with later bimetallic gauges. The early sending units will also have a narrower operating range (somewhere around 10 Ohms = Empty to around 90 Ohms = Full... values are extremely nominal, don't quote them as accurate.) The early gauge system requires that the correct terminals be used for the connections, T for Tank (green/black sending unit wire) and B for Battery (switched power in). The gauge itself MUST have a good ground connection. Likewise, if the sending unit does not have a ground connection, the tank itself must be grounded or it will not work.

If you Google for "mgaguru fuel gauge" you will find links to Barney Gaylord's web site. He has an excellent explanation of how the early gauges work and how to troubleshoot and calibrate the gauge.

 

[George Zeck]

Thanks Doug -

I was hoping to find out which sending unit will work. My gauge is fine (although from an MGB). Moss starts at 1965. When I think early, I think earlier than that?????

 

[George Zeck]

Thanks Doug -

I was hoping to find out which sending unit will work. My gauge is fine (although from an MGB). Moss starts at 1965. When I think early, I think earlier than that?????

 

[dklawson]

The earliest MGB gauges should be marked Jaeger, not Smiths. I think the transition happened about 1965 when the voltage stabilizer was added. Dates of transition at BMC were often fuzzy.

If you have the early sender and an early gauge, you can calibrate the two to work together regardless of the original application of the components. See Barney Gaylord's web site that I mentioned previously. His pages on gauge calibration are very informative. Calibrating the components to work together can be carried out on the bench using his methods. Just make sure that both the gauge and sending unit are connected to the power ground when working on the calibration. The early gauges must have a ground to work properly.