Seems that when I dropped the tank on my "69" I pulled the sending unit out and tested it with an Ohm meter and found a dead spot in it . Think I learned about how to test the sending unit from the Team Chevelle forum. but would go the ground test route first and see what happens. Bear in mind that if your gage is like mine sometimes it takes a little bit to react so be patient.
Ted ________________________________ From: Chum Nault <[email protected]> To: The Chevelle Mailing List <[email protected]> Sent: Fri, April 9, 2010 10:16:40 AM Subject: Re: [Chevelle-list] fuel sending unit Larry The fact that you are reading past full points to a bad ground and I would test that by grounding the sending unit wire directly to the tank ground if your gauge doesn't go to empty then fix the ground. If it goes to empty then it is an open circuit in the sending unit. The easiest way to bench test a gauge is with another sending unit, the sending unit is just a 90 ohm resistor. With the 12volts and ground applied to the gauge hook up a ground wire from the gauge ground to the body of the sending unit and the hook up the gauge wire from the gauge directly to the wire on the sending unit. When you move the float on the sending unit up the gauge should go to full and when it is down it should go to empty. You don't need to find the correct sending unit to do the test as almost all old GM sending units used the same 90 ohm resistance. Chum Nault -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Larry Williams Sent: Friday, April 09, 2010 9:55 AM To: The Chevelle Mailing List Subject: Re: [Chevelle-list] fuel sending unit Mine is erratic even after adding a ground. How can you check it on the bench? I have a spare. Larry [email protected] wrote: > So I restored my dash over the winter, new fuel and temp guage. the > dash turned out great. However, my fuel guage is not accurate. I put 5 > gal. in the tank and it reads past full. If I have to drop the tank to > check my grounds, should I just replace my sending unit. And if so > what sending unit do I need for a 70ss 396. It looks like dropping the > tank is going to be quite a ordeal. I think I am going to have to > partially remove my exhaust. Thanks again yall for your help. Bob
