They are CHEAP-O VDO's, all plastic!
Tommy, I had the same idea to use a resistor but that will only tell me what the current gauge is. My concern is that it may NOT be correct! I went ahead and used a variable resistor and took readings at empty and full. The current gauge is a 0-90!
I would be a "Happy Camper" if the signal wire was reading 90, 158 or 240 ohms but it's reading OPEN! As I said it seemed to stay at full forever and If I remember right it would take 10 or more gallons to fill it from 3/4's of a tank! So, bad or maladjusted sending unit? What type, no way to tell for sure with the information I have!
I really like the Autometer Cobra gauges but I want to be sure before I drop $650.00 on them only to find out my sending unit is a 0-90 ohms which the Cobra series don't support! I'm planning some road trips in the future so a fairly accurate fuel gauge is important! I guess I'll just hold off ordering until I can pull the tank and make SURE!
Thanks Guys!
:-)