I can't figure out how to make my gas gauge work.
My 71 Spider has the benefit of a 'new improved'/homemade wiring system.
Until I can save up enough for an Auto Italia wiring loom, I'm going through it and making up my own 'new, new improved'/homemade wiring system.
Engine, Headlight, turnsignals, backup lights - I got em all: BUT
I don't have a working gas gauge. Well, to be more precise, I DO have a working gas gauge and a brand in-tank new sending unit, as well as an apparently working old in-tank sending unit. However, I can't get the gauge to work.
Rather than playing with electricity and gasoline at the same time, I have made a little test rack that holds the gas gauge and the sending unit, and I've hooked up my battery charger (fused @ 5 amps and set on low charge) and tried to figure out the electrical wiring by looking that the excellent wiring diagram that Papajam provided me.
On my test rig, the low fuel light works properly - when the float on the sender is lifted, it will go out. However, the gauge either does nothing or slams up to over max - in effect the rheostat on the sending unit acts as an on/off switch rather than increasing/decreasing the current flow enough to lift the needle in a graduated manner.
The way I BELIEVE that the gauge/sending unit should be wired:
There's a red lug, a pink(violet?) lug and a grounding lug on the back of the gauge.
I believe that the red lug should be connected to the fuse box; that the pink/violet wire should run to the sending unit and the ground lug on the gauge housing should be grounded. I then also think that the sending unit should be grounded. This circuit results in the gauge slamming to max or doing nothing. Additionally it make no allowance for the low fuel light in the circuit.
Now: I have two wires that run from the dash to the sending unit on the tank - a red wire and a pink violet wire. I've checked the continuity on them and they're unbroken. Obviously the ends at the gauge should go onto the matching lugs there.
I have two sending units - the one in the car ( I don't think it's original as it has the fuel pipe on it that's capped) which has 3 (three!) electrical lugs on it. It also has a grounding lug on the top of the unit. The 'new in box' I bought on ebay only has 2 (two
) lugs and no grounding lug on it.
Further I note on the wiring diagram that the fuel pump (it's electric on the 71) should somehow be part of this circuit but it doesn't seem to be on my car.
Soooooo Help Please! How should this thing work? It's got me baffled.
Confusing me I have the original red wire
My 71 Spider has the benefit of a 'new improved'/homemade wiring system.
Until I can save up enough for an Auto Italia wiring loom, I'm going through it and making up my own 'new, new improved'/homemade wiring system.
Engine, Headlight, turnsignals, backup lights - I got em all: BUT
I don't have a working gas gauge. Well, to be more precise, I DO have a working gas gauge and a brand in-tank new sending unit, as well as an apparently working old in-tank sending unit. However, I can't get the gauge to work.
Rather than playing with electricity and gasoline at the same time, I have made a little test rack that holds the gas gauge and the sending unit, and I've hooked up my battery charger (fused @ 5 amps and set on low charge) and tried to figure out the electrical wiring by looking that the excellent wiring diagram that Papajam provided me.
On my test rig, the low fuel light works properly - when the float on the sender is lifted, it will go out. However, the gauge either does nothing or slams up to over max - in effect the rheostat on the sending unit acts as an on/off switch rather than increasing/decreasing the current flow enough to lift the needle in a graduated manner.
The way I BELIEVE that the gauge/sending unit should be wired:
There's a red lug, a pink(violet?) lug and a grounding lug on the back of the gauge.
I believe that the red lug should be connected to the fuse box; that the pink/violet wire should run to the sending unit and the ground lug on the gauge housing should be grounded. I then also think that the sending unit should be grounded. This circuit results in the gauge slamming to max or doing nothing. Additionally it make no allowance for the low fuel light in the circuit.
Now: I have two wires that run from the dash to the sending unit on the tank - a red wire and a pink violet wire. I've checked the continuity on them and they're unbroken. Obviously the ends at the gauge should go onto the matching lugs there.
I have two sending units - the one in the car ( I don't think it's original as it has the fuel pipe on it that's capped) which has 3 (three!) electrical lugs on it. It also has a grounding lug on the top of the unit. The 'new in box' I bought on ebay only has 2 (two
Further I note on the wiring diagram that the fuel pump (it's electric on the 71) should somehow be part of this circuit but it doesn't seem to be on my car.
Soooooo Help Please! How should this thing work? It's got me baffled.
Confusing me I have the original red wire