fuel gauge problems???

[adm1476]

Last year I had a new fuel tank made for my boat. I installed it and ever since the fuel gauge has not worked. The sending unit is new and came installed in the new tank. I just got around to doing some tests today, and this is what I found. When I ohm out the sending unit wire I am getting 253.2 ohms give or take. The gauge always reads empty. When I remove the ground wire from the gauge it goes to full, then goes back to empty when I reconnect it. I am pretty sure that the sending unit is faulty. But not 100% sure. I have no idea what the rating is on my sending unit. Help????

 

[gm280]

adm1476, before buying anything new, remove the fuel sender and make certain the arm isn't stuck first. If that arm is moving, see what the gauge reads as you manually move the float arm up and down. Maybe it is just stuck in an area that won't allow it to swing free. If I remember correctly the usual ohmage range is 240 ohms to 30 ohms. And I think the full setting/reading is the 30 ohm position, while the empty is the 240 ohm reading, but don't hold me to that without checking. JMHO!

 

[adm1476]

I will try that next. Thanks!

 

[Silvertip]

When you have it removed, check the bare, flat strip that connects the threaded terminal to the sending unit resistor. Sometimes that terminal gets turned so much the flat wire connection turns and contacts the metal on the sending unit. The wire from the sending unit up the support and to the threaded terminal must be isolated from any metal part of the sender. Do you have the +12 volt feed connected to the "I" terminal on the gauge? Do you have the ground terminal on the gauge connected to a good ground (such as the ground terminal on any other gauge THAT IS WORKING! The Pink sending unit wire goes to the "S" terminal on the gauge.

 

[adm1476]

I tested the gauge with a spare sending unit I had laying around and it works perfect. That is with me using the current wires that were in place in the boat. So I now know for sure the sender is bad. Going to get a new reed type this week.