OK, I can read that you do have the correct gray sender wire to the oil gauge, just wrong sender there. If you had the purple/temp and dark blue/fuel sender wires in switched locations the fuel needle wouldn't move until water gets hot. So... Does the temp gauge work correctly in the car?
Once you do get correct oil sender and hot water, then all 3 gauges read low, the limiter is faulty.
Zero ohms resistance can make make a faulty gauge do what within proper 80-10 ohms range will not.
The winding on the bimetal beam has a pale yellow spiral wound fiber glass insulation that can hardly be seen. Over the years, especially with duty of a fuel gauge that insulation gets cooked. It will restrain beam movement like a bandage on a finger. The added heat of the limiter inside this fuel gauge didn't help the life of the gauge. Take the fuel gauge out of the housing, turn it needle opening down and thump the side of the can. If specs like black pepper fall out of it, the limiter or both limiter and gauge side are toasted. I assume you will eventually open the fuel gauge to see its condition. Lets hope you only need to replace the limiter.
