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had leak in petrol pump, spraying gas in trunk. removed and repaired gasket seal. now fuel gauge shows full. and having problems re-grounding pump. i cant see where the wire origanlly was. there is a single treaded post up front, and 2 on the bracket in the back. all three bolts mount to the car chassis isolated by rubber bushings. the guage read empty before i started. at least the leak is fixed. any ideas.
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67 jag fuel gauge
- Thread starter 67jag
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What model Jag are we talking about?? In general terms there should be a wire going to the in tank sender assembly, probably green/black. This wire goes to the gauge, may turn green/red through a connector on the way. There is another wire from the voltage regulator to the gauge. The tank is grounded through the bolts generally, as is the fuel pump. Questions to ask to narrow down the fault,
1 Is the temp gauge acting up as well?? They share the voltage regulator so if it goes bad both should act up.
2 Is the correct wire hooker to the sender unit? It's normally a small circular plate on the tank top with a connector.
3 Does it work ok if the sender plate is grounded with a wire to the car body??
4 Is the sender even working?? If you remove it, ground the base plate and move the float by hand, does the gauge follow??
5 The temp gauge and the fuel gauge of that age are usually the same thing inside, if you swap the leads, does the problem follow??
6 Is the gauge case grounded??
These should help narrow down where the problem is.
1 Is the temp gauge acting up as well?? They share the voltage regulator so if it goes bad both should act up.
2 Is the correct wire hooker to the sender unit? It's normally a small circular plate on the tank top with a connector.
3 Does it work ok if the sender plate is grounded with a wire to the car body??
4 Is the sender even working?? If you remove it, ground the base plate and move the float by hand, does the gauge follow??
5 The temp gauge and the fuel gauge of that age are usually the same thing inside, if you swap the leads, does the problem follow??
6 Is the gauge case grounded??
These should help narrow down where the problem is.
67 jag e type conv.
solution 1. temp gauge fine.
2. should be correct. had not touched wires on sender since it was origanlly working.
3. no change
4. works out of tank. with original 3 wires still connected. and no additional ground to plate. works fine. put it back in and it shows full. visual check of less than 1/4 tank of actual gas.
5. swap and the problem follows. red wire and green commom wires fine. the independent green/turquise wire make a difference.
6. guage case seems grounded.
solution 1. temp gauge fine.
2. should be correct. had not touched wires on sender since it was origanlly working.
3. no change
4. works out of tank. with original 3 wires still connected. and no additional ground to plate. works fine. put it back in and it shows full. visual check of less than 1/4 tank of actual gas.
5. swap and the problem follows. red wire and green commom wires fine. the independent green/turquise wire make a difference.
6. guage case seems grounded.
Best I can say without being there to go through it is it sounds like either the sender unit is malfunctioning, through becoming a bad circuit in the tank, or perhaps the wire is bad and laying down while hooked up is a problem I did have a battery cable that did that once where it turned out to be bad at the battery post connector.
You can try running an independent wire to the gauge to bypass the harness one. And If you can borrow another sender try a swap and see if the problem goes away.
The fact that the problem follows the wire from gauge to gauge and the fact that the temp gauge isn't affected says to me that it isn't in the dash components.
You can try running an independent wire to the gauge to bypass the harness one. And If you can borrow another sender try a swap and see if the problem goes away.
The fact that the problem follows the wire from gauge to gauge and the fact that the temp gauge isn't affected says to me that it isn't in the dash components.
Do not remove sending unit or sump plate if the tank is full. They could be lower than the fuel level.
Pump ground is on the body side nut of the rubber isolators and the other end on the pump.
Test the 3 wires to the sender....
1. Make sure black wire is to a good ground, it's hidden on the body between the tank and tail lighton most cars.
2. Ground the colored wires (one at a time) for a second with the key on.
Either the low fuel level light will come on or the gauge will start to go
up. I don't know both sending unit wire colors, but green/white goes to "W" terminal. The other color goes to the other terminal. Ground to ground.
If all this works, then the sending unit is bad. They do freeze up from sitting.
Phil.
Pump ground is on the body side nut of the rubber isolators and the other end on the pump.
Test the 3 wires to the sender....
1. Make sure black wire is to a good ground, it's hidden on the body between the tank and tail lighton most cars.
2. Ground the colored wires (one at a time) for a second with the key on.
Either the low fuel level light will come on or the gauge will start to go
up. I don't know both sending unit wire colors, but green/white goes to "W" terminal. The other color goes to the other terminal. Ground to ground.
If all this works, then the sending unit is bad. They do freeze up from sitting.
Phil.