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1957 XK140 - fuel gauge inop questions
- Thread starter gtx6970
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Exotexs
Jedi Knight
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not familiar with the XK but every gasoline tank has a Sender and a Float, or some sort of similar arrangement.
Those parts send a signal to the gauge.
Perhaps your float is stuck at the bottom of the tank, or the sender itself is bad, or even something as simple as a ground wire or any wire, disconnected.
And of course, the gauge itself.
just some Generic thoughts.
Ex
Those parts send a signal to the gauge.
Perhaps your float is stuck at the bottom of the tank, or the sender itself is bad, or even something as simple as a ground wire or any wire, disconnected.
And of course, the gauge itself.
just some Generic thoughts.
Ex
Offline
I do not remember if you can see the top of the fuel tank from the boot after removing the spare? It's been a while since I've been in the back of one. But, if you check the voltage to the sender and it is good then you will have to pull sender and check. If you cannot access it by the boot, you will have to lower it and then get to it. You should pull car outside and remove drain under tank , be extremely careful and put in a fuel container, then lower tank and check sender. If it is original it may have disentegrated as the early ones were made of a cork like material. But, you can pull it and move it up a down and watch gauge to see if it works. Also, pull dash down and check for power at back of gauge. It's not hard but a little nerving with fuel and fumes lingering around. Make sure you use a good penetrating oil on all bolts before unfastening to make it easier and keep from breaking anything. Remember it's your 50+ old baby, be careful.
After cking it . Measured with key one - I have 11.7 volts on one wire at the sender which I 'THINK' is for the low fuel light and 7.5 volts on the second wire at the sender .
If I run the 11.7 voltage wire to grnd. - the light in the gauge comes on but if I grnd the second wire the gauge doesn't move.Should it ?
I've already removed the sender and float assy . measuring it with a ohmmeter . I think it's ok. As i have have a good ohms sweep from high to low . Float itself has been ck'd and is fine.
Best I can come up with is a bad gauge, as wiring is good with no resistance from the gauge to the sender.
Ps the sender is mounted on the drivers side of the tank if it matters
Thanks for the replies so far. It really helps.
If I run the 11.7 voltage wire to grnd. - the light in the gauge comes on but if I grnd the second wire the gauge doesn't move.Should it ?
I've already removed the sender and float assy . measuring it with a ohmmeter . I think it's ok. As i have have a good ohms sweep from high to low . Float itself has been ck'd and is fine.
Best I can come up with is a bad gauge, as wiring is good with no resistance from the gauge to the sender.
Ps the sender is mounted on the drivers side of the tank if it matters
Thanks for the replies so far. It really helps.
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I could not remember where sender was. My MK 1 is on top thru the boot and the XJ6s were in the fender.
Can you hook up the sender to the wires at the tank and move the sender and see if gauge moves? You might have to ground sender. My concern is the light comes on with full voltage. The light should come on at less than a 1/4 tank usually 1/8 only. Unscrew the 2 little knobs on each side of dash and pull dash down and check voltage at gauge. You might also try grounging tank and see if that works.
Find a cheap gauge or borrow one and check sender, if this does not work send gauge in for restoring. AZone has a cheap gauge, you can use it until the original is fixed.
Can you hook up the sender to the wires at the tank and move the sender and see if gauge moves? You might have to ground sender. My concern is the light comes on with full voltage. The light should come on at less than a 1/4 tank usually 1/8 only. Unscrew the 2 little knobs on each side of dash and pull dash down and check voltage at gauge. You might also try grounging tank and see if that works.
Find a cheap gauge or borrow one and check sender, if this does not work send gauge in for restoring. AZone has a cheap gauge, you can use it until the original is fixed.
jessebogan
Jedi Knight
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You should have some small resistance in the wire to the gauge. If you have an open, then the wire is broken. If you connect a ground at the gauge ( Same wire color as at the sender) Then it should go to full. If not, and the gauge has power, then gauge is bad. I have had great service from Nisonger on Smiths gauge rebuilds over the years,
If you look behind the left rear wheel, you'll see the side of the tank - sort of square on the side with rounded corners. In the middle of it is the round sender. Yes, it's in the middle, so if there's a half tank or more of fuel, you've got problems. The sender has two wires to it. One is for the level, the other is for reserve light. There is no ground wire - the tank is grounded. If you ground each wire one at a time - you don't have to take them off - one will make the guage read full, the other will turn on the low level indicator light in the speedo. If both those happen, then your sending unit is bad. 9 out of 10 have a rusted sender, the float is steel. Once you've pumped out most of the gas, you can unbolt the sender and replace. The sender is made of white metal, steel, copper, and who knows what else. They all rot differently to stop the arm from moving.
Phil.
Phil.
Offline
Phil said:
Truer words were never spoken.
If the resistance is gradually raised/lowered as you move the sender thru the range, it would seem sender is okay. The float is the only other thing to be suspect but you checked it. Grounding the two wires at the sender should get you both the warning light and a gauge at "full". If not(and there's voltage to it), the gauge is likely at fault.
And I'll reinforce Jesse's Nisonger recommendation. Good service for decades from 'em.
Aside: If you checked the float in water, it may not leak... MILK is what to use. Honest! Milk will go thru pinholes water will not penetrate. Force the float to sit at the bottom of a glass of milk for an hour then shake it before you deem it "good".