Great guide, many thanks. I'm having a problem with my fuel reading. Always reads empty, I did the diagnostics on the tan feed wire form the sending unit and all seems well from there back to the gauge (it reads full when disconnected and empty when grounded) I also have a good ground from the sender to body so I'm not sure where to turn now, the sender unit is new.
If it always reads empty,, the tan wire is grounding itself someplace. I would examine the short wire from the plug in the trunk to the sender itself. Try running a jumper wire right to the sender itself I've also learned that just because a part is new doesn't make it nessecarily good
Cheers, I will have a look. One thing I can't understand though is that if the tan wire is grounding itself wouldn't the fuel gauge read empty , not full when I pull the wire from the sending unit?
Your pulling it from the plug in the trunk right? There is a possibility that the wire from the plug to the sender is pinched and grounding itself
Its really a simple circuit. There arent many parts involved here. The next step might be to get behind the gauge and run a wire from the sender right to the back of the gauge
So, today I pulled the sender from the tank after using up some fuel. I tested it and the ohm readings are correct form empty to full (0 - 90)so the sender good. I wired it up in situ, the fuel gauge has come to life but only reads just over 1/4 when float is at full position, when float is half full position the gauge reads half way between empty and a quarter.
Jason will probably be best to chime in on this but I would say that's the gauge. Sounds like the gauge is not reading the resistance correctly and therefore not displaying the correct reading.
Jason, I know that this is an old thread, took me a bit to find, but I just wanted to thank you for writing it up. The gas gauge in my car went to the above empty and now I know how to trouble shoot it!
What about when it is full the needle is in the middle of the H in hot. But goes down when you use fuel? Anyone have any idea where the sending unit wiring is on a 71 Sportwagon? Thanks Tim
This is what I have in my GS, https://www.robbmcperformance.com/products/1069_gmsend.html This one includes wagons, https://www.robbmcperformance.com/products/1076_gmsend.html Or stock for the GS455, https://www.rockauto.com/en/catalog...+v8,1379763,fuel+&+air,fuel+sending+unit,4436
