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Sending Unit Adjustment?

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Bill_Reid

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I have just replaced the fuel gauge in my '60 Sprite with a rebuilt one from AH Spares in the UK. The problem is that the gauge will only read half full. I tried with a loaner gauge ......same thing....reads no more than half full. I have tried with the original sending unit and a new one from Moss. I have the sending unit out of the tank so that I can move the float arm, and I have connected a ground wire to the unit and the car body so as to complete the circuit. I don't think the gauges are the problem since one has just been rebuilt and the other belongs to my mechanic who uses it as a test gauge......must be the sending unit, but is it possible that both could be that inaccurate? Can the unit be adjusted? Are these things just poor quality and I need to keep trying til I get a good one? Anyone have thoughts about this problem? Thanks.....

Bill
 
Bill, I can't respond but am interested - Mine registers full, but then runs out of gas (literally) at 1/4 tank. I presumed it was the float (much like a toilet tank) but now am curious
 
Just advise, yep they are adjustable. there is a screw or two that adjusts the amount of elec provided. Understand you need to know what you are doing and I do not. Is best adjusted on the bench with an instrument or two.
 
I know when mine hits Empty...it means it is empty! No "reserve tank" with this one.

Glad to see that you're an optimist. A pessimist would say that the tank is registering at half-empty.
 
Search this forum on fuel sended or gas gauge. Kim who used to hang out here a lot did some extensive research on the three different senders that need to be matched with corresponding gauges. He also orovided some advice on testing.
 
Try reading ~THIS~

It's for MGA but is very similar.

(don't forget to go to the bottom of the page and click the green arrow...eventually you'll get to the page with the sender info)
 
For general background on how the early (pre-stabilizer) gauges work, Google for "MGA Guru Fuel Gauge". Barney Gaylord's site has sections that both explain how the gauge works and how to calibrate it.

EDIT: DOH !!! Nial and I were typing at the same time. His link above is to Barney Gaylord's site.
 
Haven't reviewed Barney's site though I know it's hard to beat but I had that problem on my BE till I realized that the DPO had not reconnected the ground wire to the back of the gauge bracket where it was from the factory. Gauge worked perfectly after that so recommend attaching the wiring loom ground wire to the gauge bracket before you do anything else if you have not already done so.
 
On my BE, I also added a ground wire from the sending unit to the tank. Sometimes the ground is lost through the gasket and sealers between the sender and the tank.
BTW: I have not had the best luck with new sending units....currently Bill's car has the third one in it since 2010! Last time the float sprung a leak.
Scott in CA
 
Hi Scott, Bill here. Currently the fuel gauge only drops to 1/4 and not to empty when I turn off the key. When I fill the tank it goes to full and then it slowly drops down as I use gas, until it gets to 1/4 tank again. Any ideas about this.

On another note 60 FROG took third place at the prestigious La Jolla Car Show two weeks ago. The car was entered in the Modified European Sports category in the non concours section of the show. I had the RED Top and the side curtains on it. The competition was pretty stiff so I am happy with my first "SCOTTIE AWARD" of the year.
This Sunday I will be driving 60 FROG in "Rolling British CAR DAY". The Sunday after that it will be shown at the "Motor Cars On Main Street" car show in Coronado.
Last year I won the Peoples Choice Award there with 59 Diamond. To be honest my grandson was very instrumental in me getting that award as he touted the car to people and made sure they put it on their ballot.
 
If it only goes to 1/4 with the key off then there is probably some mechanical restriction or physical interference inside the gauge itself. There is an internal weight that pulls the needle to the empty peg when there is no current flow. That is the only thing that pulls the needle to empty with the key off. Of course, the same thing would happen if you mounted the gauge significantly off from vertical in the dash because the weight wants to be at the lowest point possible and the peg beyond empty normally stops it.
 
Dang! That was simple. I went out to the garage and turned the gauge to vertical and WALA the needle went to empty. Thanks a lot. I wish everything in life was that simple.
 
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