62 corvette fuel guage
#1
Instructor
Thread Starter
62 corvette fuel guage
I recently replaced the dash pad in my corvette and when I got the =
> instrument panel back in and wired, the fuel gauge pegs to past full as =
> soon as I turn the key to on. I have a wiring diagram and I am sure I =
> have the correct two wires tied to the guage. I noticed a piece of =
> rubber or something between the two terminals and below the nuts behind =
> the gauge and wondered if I might have damaged that when I reinstalled =
> the wires and nuts or If I may have somehow put a screw through the =
> brown wire going to the gas tank when reinstalling the left kick panel. =
> I do not have a diagram for the gauge so do not know what may be causing =
> this.
Thanks
> instrument panel back in and wired, the fuel gauge pegs to past full as =
> soon as I turn the key to on. I have a wiring diagram and I am sure I =
> have the correct two wires tied to the guage. I noticed a piece of =
> rubber or something between the two terminals and below the nuts behind =
> the gauge and wondered if I might have damaged that when I reinstalled =
> the wires and nuts or If I may have somehow put a screw through the =
> brown wire going to the gas tank when reinstalling the left kick panel. =
> I do not have a diagram for the gauge so do not know what may be causing =
> this.
Thanks
#2
Team Owner
If the tan wire going to the tank is not connected (open) the gauge will peg full. If that wire is shorted to ground, the gauge will read empty. Here's a gauge diagram, if that helps.
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norlem (03-13-2019)
#3
Instructor
Thread Starter
I had the pink and brown wires reversed to start with and the needle pegged. I then switched the pink and brown wire to the correct terminals and the needle still pegs. I checked the wiring and does not appear there is an open circuit. Could I have damaged the gauge by putting the hot lead to the side the tank sender should have been?
#4
Race Director
I believe you have full a ground going on, not an open circuit.
If you damaged the insulators at the studs on the back of the gauge, or twisted the studs sideways so they contact the gauge body where they pass through the holes, you would get this effect.
Doug
If you damaged the insulators at the studs on the back of the gauge, or twisted the studs sideways so they contact the gauge body where they pass through the holes, you would get this effect.
Doug
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norlem (03-14-2019)
#5
Team Owner
If the tan wire on the gauge's "S" terminal is open it will read full...if you ground that terminal the gauge should read empty.
Here is the JohnZ article with the "quick and dirty" checks a few paragraphs in on the first page:
Here is the JohnZ article with the "quick and dirty" checks a few paragraphs in on the first page:
Last edited by Frankie the Fink; 03-13-2019 at 05:51 PM.
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norlem (03-14-2019)
#6
Team Owner
Disconnect the tan wire at the back of the gauge, read with an ohmmeter from the tan wire connector to ground. You should get between 0 and 30 ohms. If you get anything significantly over 30 ohms (including an open circuit, you either have an open wire to the sender, or the sender is open either at the connection or internally. To get correct deflection of the gauge, that wire has to read between zero and thirty ohms depending on how much gas is in the tank.
Pay attention to what I (and Frankie) told you. It is opposite of what you would think, an open wire to the sending unit causes FULL deflection, a short on that wire causes an empty reading. So..... If you short that tan wire to ground with it connected to the gauge, you should get an empty reading. With that information, you can eliminate or determine the sending unit and wiring as a problem.
DON"T SHORT THE PINK WIRE TO GROUND, it's battery voltage.
Pay attention to what I (and Frankie) told you. It is opposite of what you would think, an open wire to the sending unit causes FULL deflection, a short on that wire causes an empty reading. So..... If you short that tan wire to ground with it connected to the gauge, you should get an empty reading. With that information, you can eliminate or determine the sending unit and wiring as a problem.
DON"T SHORT THE PINK WIRE TO GROUND, it's battery voltage.
Last edited by 65GGvert; 03-13-2019 at 08:35 PM.
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norlem (03-14-2019)
#7
Drifting
Member Since: Mar 2018
Location: Oklahoma
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C1 of Year Finalist (appearance mods) 2019
Someone ought to make a book out of the combined articles for us rookies.
Butch
#8
Team Owner
I've never once gone wrong following John's online advice or his articles - I have a ton of them in my digital library..
Between John, Tom Parsons, DZvette and some others all of our C1 cars are better for their experience and sharing..
Between John, Tom Parsons, DZvette and some others all of our C1 cars are better for their experience and sharing..
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C.T. (03-14-2019)
#9
Team Owner
Thanks Frankie! I'm printing off all these old articles by John, that you and others post here. I missed them the 1st time around and find them way more helpful than the factory SR-12 manual.
Someone ought to make a book out of the combined articles for us rookies.
Butch
Someone ought to make a book out of the combined articles for us rookies.
Butch
https://www.corvetteforum.com/forums...aq-thread.html
https://www.corvetteforum.com/forums...ky-thread.html
#11
Team Owner
And just to add to the confusion C1 and C2 fuel gauge/sending units work the same....
C2s are entirely different....nobody knows why...
C2s are entirely different....nobody knows why...
#12
Drifting
Member Since: Mar 2018
Location: Oklahoma
Posts: 1,606
Received 419 Likes
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C1 of Year Finalist (appearance mods) 2019
Something like these at the top of the C1/C2 forum?
https://www.corvetteforum.com/forums...aq-thread.html
https://www.corvetteforum.com/forums...ky-thread.html
https://www.corvetteforum.com/forums...aq-thread.html
https://www.corvetteforum.com/forums...ky-thread.html
Regardless, I've saved them to my desktop so I'll have them going forward as this looks like some very good reading. Thank you 65GGvert!
Butch
#13
Team Owner
#14
Team Owner
For some reason C2's run a separate 12-volt lead back to the sending unit. Somewhere along the line someone must have thought that was better