JeffB2
Well-known member
Does it have the voltage regulator I referred you to or not ? If you put 12 volts to a 6 volt gauge it will peg it.
Gas sender
- Thread starter Oilslickwillie
- Start date
Oilslickwillie
Senior Member
Car has a under dash fuel gage that is for 12 volt. When I grounded the sender it pegged to full.
Something to bear in mind when looking for a replacement fuel gauge sender:
1956 Fords and earlier used a "King Seely" fuel gauge system. The sender sends on/off electrical power to the gauge with the "on" time corresponding to the amount of fuel in the tank. All of the replacements I've seen are simple variable resistors, with the amount of resistance corresponding to the tank level. This is not the way the original gauges were designed to work. The replacement senders will cause the gauge to respond, but not accurately - especially at the lower tank levels where you need accuracy the most. Do a search on this forum to learn more. Unfortunately, original senders a difficult to find and expensive.
1956 Fords and earlier used a "King Seely" fuel gauge system. The sender sends on/off electrical power to the gauge with the "on" time corresponding to the amount of fuel in the tank. All of the replacements I've seen are simple variable resistors, with the amount of resistance corresponding to the tank level. This is not the way the original gauges were designed to work. The replacement senders will cause the gauge to respond, but not accurately - especially at the lower tank levels where you need accuracy the most. Do a search on this forum to learn more. Unfortunately, original senders a difficult to find and expensive.
JeffB2
Well-known member
Now the "rest of the story"
The gauge has to be the same ohm resistance to match the sender,if the gauge is GM resistance it won't work with a Ford sender,many aftermarket gauges have a different resistance and have to be matched to the same brand of sender.JeffB2 - Please look in your 1954 Ford service manual as to how these King Seely gauge systems work. My 1956 manual describes it, and I believe 1954 would be the same except 6 volt instead of 12 volt. It's also described in the Motors Manual of this era. The King Seely Sender consists of a bi-metalic beam with points on the end. The beam is wrapped with induction wire which heats the beam when points are closed. When the beam gets hot, it bends (due to the bi-metalic construction) which causes the points to break. The beam cools and the points make contact again. This cyclic on/off current flow produces an average current which corresponds to the tank level. The GM gauges and other non King Seely gauges depend on the resistance in the Sender. The King Seely does not. What the after market suppliers of these Ford fuel gauge Senders have done is to produce a unit that IS a variable resistor (like GM and others). They use a constant current flow (instead of pulsating) and vary the resistance (controlled by the float level) in an attempt to TRY to obtain a reasonably accurate gauge reading. For my 1956 12 volt gauge, a 3 volt steady electric supply will cause a gauge reading of 1/2. 4 volts will cause the gauge to read 3/4. In fact, this is the method described in the 1956 Ford manual for testing the gauge. What becomes troublesome is for the variable resistor Sender to send these low voltages accurately, and even lower voltages for 1/4 tank and below. Bottom line - the King Seely Sender is NOT a variable resistor as are GM (and other) Senders. Therefore, resistance matching is a non issue with these original Senders. I know you have a lot of experience and knowledge with these old Fords, but look up the operating details of these King Seely units and see if you agree.
JeffB2
Well-known member
You missed my point,he stated he mounted a gas gauge "under the dash" that kind of tells me it is not a stock Ford gauge. Thus "the rest of the story" quote. In reference to the 1956 Ford it was for a long time the only all 100% 12 volt car,in '57 Ford went back to using 6 volt gauges which continued into the early 80's.
Daves55Sedan
Well-known member
If the sending unit is bad, you have two options.
1) buy one of those cheap ($45.00 if you call that cheap) aftermarket sending units that are available and many resto parts suppliers.
2) send your bad unit into Bob's Speedometer or one of the other guys that refurbish instruments. I just got one back for my '55 Ford Courier wagon from Bob's. $190.00 to repair incl shippg cost. That's way more expensive but it will work properly.
Some folks say that the aftermarket sending units are not fully compatible with the old gauges and therefore the guage may give an erroneous reading.
1) buy one of those cheap ($45.00 if you call that cheap) aftermarket sending units that are available and many resto parts suppliers.
2) send your bad unit into Bob's Speedometer or one of the other guys that refurbish instruments. I just got one back for my '55 Ford Courier wagon from Bob's. $190.00 to repair incl shippg cost. That's way more expensive but it will work properly.
Some folks say that the aftermarket sending units are not fully compatible with the old gauges and therefore the guage may give an erroneous reading.