Fuel Gauge Doesnt Work

[beebeecivic]

Hey guys, My 78' 280z fuel gauge is not working. When I turn the key the gauge moves but does not go between the empty and fuel area, instead it sits to the side. This makes me believe that my fuel sending unit is ok, but the gauge itself is the problem. If anyone had this problem.. was a simple gauge replacement the fix or am I wrong that my sending unit is at fault.

thanks!

-bee

[EScanlon]

WHICH side?

Completely FULL or

Completely EMPTY?

FULL: You have a short in the wiring, and the return lead from the sensor is grounding itself, yielding a 0 ohm reading and therefore a "full" tank.

EMPTY: Probably the same thing, but your wires are inverted.

Could also be just the wires being inverted and the wire expecting to be grounded is being provided power. (This second item is a long shot though.)

To check if your float sensor is reading right, remove the terminals AT the sensor in the tank, and do a resistance reading. If you yield anywhere between 10 and 90 ohms (depending on how full your tank is) your sensor is fine.

Now do a 12v power check between the Yellow wire and ground, it should be about 12v (don't fret if it's a dash lower). If you do NOT, then that tells you your wire is compromised to ground someplace on it's route to the tank.

FWIW

E

Edited September 19, 2009 by EScanlon

[beebeecivic]

Its on the completely empty side, like when i turn the key it will move (but not past the Empty)

[EScanlon]

So what you're saying is that while the needle "moves" it doesn't register anything.

Check to make sure the wiring AND the gauge are ok.

AT the tank, connect the two wires going to the sending unit with a jumper. One of those wires is a spade connector with a lock tab. Be careful pulling that off. If you're not sure of how, or are worried you might hurt it, simply connect a wire between the two terminals on the sender.

Your gauge should now read completely FULL. (0 resistance)

If it does NOT, then there is a different problem. Could be the gauge itself, or the wiring to the gauge.

Check that and post back.

E