'63 Fuel gauge not working

[hanko mechanico]

57 lincoln Capri. My fuel sending unit Ranges from 198 to 80 ohms. Is that normal as my gauge only read empty. Unit wire to gauge has continuity and voltage is correct to gauge

[Lee]

If your sending unit is original, and is giving smooth and steady resistance readings throughout the range of travel, then I'd say it is correct. I don't believe the manual mentions the specific resistance. If you (very briefly) short the wire at the sender to a good ground, does the gauge then move toward full? It should. You may want to check that the tank is well grounded, and that the sending unit is grounded to the tank through the lock ring.

[hanko mechanico]

Yes the gauge goes to full with wire grounded out. The gauge tries to move a little off empty but tank is about 3/4 full. I'm not sure if its the original sender or not. I believe there is a few with the 6 screw mount that will fit but aren't necessarily correct and I can't find a picture of the correct one. The one in my tank has a straight rod on the float which I don't see on any other sending units with the 6 screw mount.

[hanko mechanico]

According to Mark 11 enterprises the sending unit for a 57 lincoln is extremely rare and they can't locate one.Might have to add resistors to make it work properly

[Lee]

According to Mark 11 enterprises the sending unit for a 57 lincoln is extremely rare and they can't locate one.Might have to add resistors to make it work properly

This topic may be helpful. I am thinking that it may be possible to rivet or in some manner attach a Ford sender to the Lincoln 6 bolt mount plate. If all else fails, it sounds like a 57 Ford tank swaps in.
https://www.thelincolnforum.net/phpbb3/ ... hp?t=11805

[tomo]

Look carefully at the sending unit tank side. If it appears that the float arm moves a diaphragm, you have the King-Seeley current balancing sending unit and gauge. The most common problem with these sending units is dirty contact points inside the unit. The way to repair this type of sending unit is to pry off the top of the unit and gently spray the contact points with a good electrical cleaner like Hosa D5S-6 CAIG DeoxIT 5% Spray Contact Cleaner. Be very careful of the thin hair like wires that connect to the contact points as they break easily. Once you have sprayed the contacts, move the arm through its travel length several hundred times and then check for 0 ohms from the center contact to the case. If you have 0 ohms yoiur sending unit is fixed. The arm moves the diaphragm which changes the time that the contact points are closed, regulating the current in the gauge and sending unit.

The resistant type sending unit can also be cleaned with the contact cleaner. Just spray it on the resistance wire and wiper and then check the operation by connecting the wire to the gauge, connect a jumper from the case of the sending unit to a good ground and then move the arm through it's range while observing the gauge. It should move from full to empty as you move the arm.

[hanko mechanico]

Thanks tomo but my sending unit float is connected directly to the contact that travels along the resistor. I have cleaned the contact and resistor wire with no change in ohm readings. I've tried temporary resisters with no change. Possibly not installing resistors correctly though. The sending unit looks alot newer than the tank and has no identification on it so I'm sure it"s no original but seems to fit correctly as far as float travel. Just need to know how to install a 100 ohm resistor correctly or possibly missing something like a poor contact. Does someone know how and where to put the resistor in parallel in the sender circuit?

[Lee]

I don’t believe your plan to add a resistor will work very well. You may get some needle movement, but it won’t cover the entire gage range. If you add a 100 ohm resistor in parallel (series won’t work at all) to your 80 - 198 ohm sender, your new effective resistance range will only be 44 to 64 ohms, so the empty to full reading on the dial may only be ≈ 1/4 to 1/2. If you want to try, here’s a schematic (basically from the sender wire to ground).

[hanko mechanico]

Thanks Lee. I didn"t install resistor correctly. I was trying only a 10 ohm just to see if there was a change ( don't have a 100 ohm yet). Don't know the formula for resistance but obviously 200 ohms added will make things worse at the full end.Would a poor connection increase the ohms?

[Lee]

The problem is that any resistor you add will reduce the working range/ sensitivity of the gauge. Here’s the formula, you can see for yourself. R1 can represent your sender resistance extremes, R2 can be any random parallel resistor, Req = the resistance that circuit “sees”.

Req = (R1xR2)/(R1+R2)

[Dan Szwarc]

Oh... My... GLOB electrical formulas. That’s my bread and butter.

You can’t take a 198 to 80 ohm sweep and turn it into a 118 to 0 ohm sweep without using some powered electronics.
The sender is simply built wrong. You’d need to turn the reference resistance you have into the dynamic voltage range you want. It’s called a transfer function and there may be some canned circuits out there that can be hacked in, but you need an engineer to develop the parameters then design or cobble the circuits together to add between the gage and the sensor.

I’m on mobile so I can’t easily determine the parameters but if I have time, I’ll go back later and check the thread.

The easier solution to to just replace the sending unit or rewind it yourself to the proper range needed.

[frasern]

I may have found 2, '57 Lincoln parts cars, but you may have to take the whole thing. PM me for details if interested.

[hanko mechanico]

Fraser are these lincolns in western Canada. I'm located in Alberta west of edmonton. I know I won't be able to modify my sender as i know it's not original now as it has a complicated( for me) printed circuit.

[frasern]

Your car will have a 6 volt gauge, with a reducer, anything with a printed circuit is going to be 12 volt, I think.
Both cars are within a few miles of North Battleford, I'm not sure of the year of the the closer one. Anyway, there is a wrecking yard here, closed for about 30 years, which has recently re-opened, I was in there last fall and think I saw a '57. If you go to the BVAC facebook page, and dig back, you will see some details about a sale coming up there in June. Or phone me, 306 445 6847.
The other car is a '57 convertible that I mentioned in another post, different owner. He will sell it, or parts, but I don't think it will be cheap.

[tomo]

You can try a replacement sending unit for a 1936-1955 Ford. They will read somewhat accurately in your tank. The resistant units that are replacing the current matching units do not give as accurate readings as the original ones, but they will tell you when your tank is full or empty. the one from Dennis Carpenter seems to be one of the more reliable ones.
https://www.dennis-carpenter.com/trucks ... nding-unit

If you have a Shop Manual that describes the sending unit operation, and it is the King-Seeley type, I have a NOS truck sending unit that I would sell. You would have to fabricate the wire to hold the float and the bend it to read correctly in your tank. I would use the wire from the sending unit that you have.