Fuel Gauge/Sending Unit not working
Thread Starter
Racer
Joined: Jun 2009
Posts: 290
Likes: 7
Fuel Gauge/Sending Unit not working
So my fuel gauge or my sending unit isn't working. Can anyone describe how I would go about finding out which one is borked? The fuel gauge just goes all the way up (past F as far as it can). What's some troubleshooting I could do?
Team Owner
Joined: Sep 2006
Posts: 31,267
Likes: 4,361
From: Westminster Maryland
Hi m,
Since your car has been modified I believe it would help if you described the tank and sender to help determine what it is. They changed over the years so the trouble shooting procedures changed too.
Regards,
Alan
You may want to check this thread.
http://forums.corvetteforum.com/c3-t...e-testing.html
Since your car has been modified I believe it would help if you described the tank and sender to help determine what it is. They changed over the years so the trouble shooting procedures changed too.
Regards,
Alan
You may want to check this thread.
http://forums.corvetteforum.com/c3-t...e-testing.html
Last edited by Alan 71; May 27, 2010 at 04:46 PM.
Thread Starter
Racer
Joined: Jun 2009
Posts: 290
Likes: 7
Thread Starter
Racer
Joined: Jun 2009
Posts: 290
Likes: 7
Hi m,
Since your car has been modified I believe it would help if you described the tank and sender to help determine what it is. They changed over the years so the trouble shooting procedures changed too.
Regards,
Alan
You may want to check this thread.
http://forums.corvetteforum.com/c3-t...e-testing.html
Since your car has been modified I believe it would help if you described the tank and sender to help determine what it is. They changed over the years so the trouble shooting procedures changed too.
Regards,
Alan
You may want to check this thread.
http://forums.corvetteforum.com/c3-t...e-testing.html
I'm sorry. I'll check out that thread. Thanks 
Drifting
Joined: Jul 2009
Posts: 1,534
Likes: 14
From: Dallas-Fort Worth TX
I had similar issues with mine, never actually resolved them either. I did all the ohm testing, pulled the sender out of the tank. It worked fine out of the tank, go figure.... but it would only go from F to 1/2 and then stop when back in the tank. I checked the tank for interference to ensure nothing was hitting the sending unit arm. Such as some tanks have rubber bladders or whatever. Still puzzled as to why I get that fubar readings. But I am busy with an engine build and the issue has been shelfed for now.
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Cruising
Joined: May 2006
Posts: 10
Likes: 1
Troubleshooting Sending Unit
1979 Sending Units operate between 0 - 90ohms of resistance. Disconnect Sending Unit wire from top of gas tank - Gas gauge should peg past full. Touch the disconnected wire to ground and the Gas gauage should peg past empty. If the above indications are valid your sending unit is defective.
EWJammer - SD
EWJammer - SD
Racer
Joined: Nov 2009
Posts: 423
Likes: 7
From: Utah
Willcox has some help.
This one's for 68-76, they have others. Just search their "Install & Repair Help". A lot of good info in there.
http://willcoxcorvette.com/repairand...lp.php?hID=276
This one's for 68-76, they have others. Just search their "Install & Repair Help". A lot of good info in there.
http://willcoxcorvette.com/repairand...lp.php?hID=276
Drifting
Joined: Jul 2009
Posts: 1,534
Likes: 14
From: Dallas-Fort Worth TX
Here is a dumb question for tonight. I have similar problems with fuel gauge. The gauge works perfect when I have the unit out of the tank and do all the ohm testing, etc.
I did the string test. Tied a piece of string to the sender unit arm. Reinstalled unit back in tank. When I pull on the string replicating a full tank, fuel gauge goes to full. When I let go of the string I hear a clank. The tank has about 10 gallons in it. So I should not be hearing a metallic sound when I let go of the string.
The dumb question is- can a floater go bad (aka stop floating?) Sure sounds like that is the problem. Like its sinking right back to the bottom.
I did the string test. Tied a piece of string to the sender unit arm. Reinstalled unit back in tank. When I pull on the string replicating a full tank, fuel gauge goes to full. When I let go of the string I hear a clank. The tank has about 10 gallons in it. So I should not be hearing a metallic sound when I let go of the string.
The dumb question is- can a floater go bad (aka stop floating?) Sure sounds like that is the problem. Like its sinking right back to the bottom.
Cruising
Joined: May 2006
Posts: 10
Likes: 1
Sending Unit Test
Either you do not have 10 gallons of gas (you said you hear a clank - that sounds like the bottom of you tank) or your sending unit is not floating. Since you already have the sending unit out test in a bucket of water and see if the float floats. By the way, Your low fuel light should light at 2 gallons as well.
Rob - SD
Rob - SD
Drifting
Joined: Jul 2009
Posts: 1,534
Likes: 14
From: Dallas-Fort Worth TX
Well it is definately hitting something, which makes me thing the floater is not working. Not sure if that is possible, but the unit works perfect outside the tank as far as the gauge goes. I will have it removed here in the week or so, and I will test the floater. I was just wondering if anybody has ever had this problem with a floater.
Thanks,
Thanks,
Racer
Joined: Jan 2007
Posts: 256
Likes: 3
fuel gauge stops at 3/4 at bench
Bringing this thread up again add it didn't really help my situation. I connect a wire to the center ground on my temp gauge and over to negative terminal on my battery. I connect another wire to 12v terminal on fuel gauge and positive terminal. The gauge went to 3/4 full. Is my gauge bad? It the tests recommended I either bury the needle past E or drive it to 3/4.
help?
help?
