Fuel gauge showing empty

[mathijskok]

E36 320i Convertible, 1996 build

Last night I filled the tank only to find the gauge showing full empty with the warning light burning. I checked out the Haynes but I can't really find where to start looking. Anybody any suggestions?

Mathijs

[Hamfisted]

Lift out the rear seat and check the terminals on the fuel quantity senders. They get corrosion on 'em and kill the signal to the gauge. If you have a multimeter check that there is resistance between the pins on the sender itself, not zero or infinite resistance, but 100-300 ohm resistance.





Mike

[mathijskok]

Originally Posted by Hamfisted

Lift out the rear seat and check the terminals on the fuel quantity senders. They get corrosion on 'em and kill the signal to the gauge. If you have a multimeter check that there is resistance between the pins on the sender itself, not zero or infinite resistance, but 100-300 ohm resistance.

Mike

Okodoki, will do that tomorrow. I know my electrics so I should be able to get that. I found the sensors, but not yet how to detect if they were faulty. I did clean them though, no results. But with your help I should at least be able to detect WHERE the problem is, great support, thanks!

Funny, I found a whole bunch of little seedpods in the left one, obviously some mice used it for a while. It's a great little hiding place for them. Means I will have to check the wires better of course. Those guys eat wires.

[saltshaker185]

Originally Posted by mathijskok

Okodoki, will do that tomorrow. I know my electrics so I should be able to get that. I found the sensors, but not yet how to detect if they were faulty. I did clean them though, no results. But with your help I should at least be able to detect WHERE the problem is, great support, thanks!

Funny, I found a whole bunch of little seedpods in the left one, obviously some mice used it for a while. It's a great little hiding place for them. Means I will have to check the wires better of course. Those guys eat wires.

MMMMM MICE MUNCHIES!

[mathijskok]

Originally Posted by Hamfisted

Lift out the rear seat and check the terminals on the fuel quantity senders. They get corrosion on 'em and kill the signal to the gauge. If you have a multimeter check that there is resistance between the pins on the sender itself, not zero or infinite resistance, but 100-300 ohm resistance.

Mike

221 ohm on one, infinite on the other (the one with the fuel pump). Sounds like a clear case of replacement or is there anything to check when I take out the sensor? And when I do take that bit apart, makes it any sense to replace the fuel pump as well? Car done 120.000 kilometers (say 75.000 miles).

[Hamfisted]

Originally Posted by mathijskok

221 ohm on one, infinite on the other (the one with the fuel pump). Sounds like a clear case of replacement or is there anything to check when I take out the sensor? And when I do take that bit apart, makes it any sense to replace the fuel pump as well? Car done 120.000 kilometers (say 75.000 miles).

That's not a lot of miles for the sensor to already go bad . But that side comes as a complete replacement set (pump and all...) and it's the more expensive side obviously ($160-$175). I thought you might get lucky and it would just be dirty terminals.





Right side fuel quantity sender and fuel pump unit ..... one piece.
The left side quantity sender has no fuel pump attached....













Mike

[mathijskok]

Well, I'll order the bit and replace the whole thing, seems simple enough. Thanks for the superb help Mike! Certainly saved me a hell of a lot of money!