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Fuel Gauge Problem

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Old 07-02-2018, 11:35 AM
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MBrianB
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Default Fuel Gauge Problem

Well, I was starting to install fuses in the '72 for the first time with the new harness and everything else new.

Installed the gauge fuse and turned the key to on.....started to smell something getting hot......no smoke or sparks......nosed around the dash and the gauge cluster as they are all hanging out, not installed.....smelled it above the gauge cluster.....felt around and the fuel gauge ground was burning hot to the touch.

I pulled the connector to the fuel gauge. There is NO gas in the tank at all and never has been.

Will this self correct when the tank gets some fuel? Is the gauge faulty?

??????

Brian
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Old 07-02-2018, 12:40 PM
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7T1vette
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No. You have something wired incorrectly. Actually, I can't imagine taking time to search out the source, once I smelled something burning!!
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Old 07-02-2018, 12:48 PM
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Usually electrical shorts melt, ignite, blow fuses immediately. Since this entire car is rebuilt and all the harnesses are new but not tested I don't have any other way to trace the problem. I will check the gauge sender for correct wiring.

I just wonder why it was the ground on the gauge that was hot?

I thought it was the clock as that is usually the first to self destruct.
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Old 07-02-2018, 01:02 PM
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Make sure that the TOP and BOTTOM terminals are centered in the holes in the metal that they attach to.
The insulator should keep those two terminals centered and away from the metal can they go through.
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Old 07-02-2018, 01:13 PM
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Found the test procedure for the fuel gauge and sender on the Willcox site. Thanks Willcox!
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Old 07-02-2018, 11:20 PM
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The Corvette is a rather unique American vehicle because of the high importance for proper grounding of the various electrical circuits. If something is not grounded well, that device will "hunt" for another ground to use. I suspect that is what is happening to you, based on your "hot gauge ground" symptom. Since only the ground was hot, there is likely some other device that is not grounded properly and is getting ground via that gauge terminal ground line. When you insert a specific fuse, it is unusual for only one electrical item to be powered. Investigate the common power string and what all received positive power during your test.; then check to see that those items were all grounded properly.
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Old 07-02-2018, 11:54 PM
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Originally Posted by 7T1vette View Post
The Corvette is a rather unique American vehicle because of the high importance for proper grounding of the various electrical circuits. If something is not grounded well, that device will "hunt" for another ground to use. I suspect that is what is happening to you, based on your "hot gauge ground" symptom. Since only the ground was hot, there is likely some other device that is not grounded properly and is getting ground via that gauge terminal ground line. When you insert a specific fuse, it is unusual for only one electrical item to be powered. Investigate the common power string and what all received positive power during your test.; then check to see that those items were all grounded properly.
the ground for the gauge cluster appears to be at the temp gauge. The dash tach and speedo are each grounded individually. Where should I begin to look?

Last edited by MBrianB; 07-10-2018 at 02:19 PM.
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Old 07-03-2018, 12:09 AM
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The main GROUND for the metal can starts at the center terminal of the temperature gauge.
All the other gauges get there ground from the nuts that hold the gauges to the metal can.




Did you see if the fuel gauge terminals are centered in the holes?
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Old 07-10-2018, 02:18 PM
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Originally Posted by Peterbuilt View Post
The main GROUND for the metal can starts at the center terminal of the temperature gauge.
All the other gauges get there ground from the nuts that hold the gauges to the metal can.




Did you see if the fuel gauge terminals are centered in the holes?
Sorry it took so long to get back to this. I had other wiring and starter issues come up.

I checked the terminals on the fuel gauge and they are definitely not touching the case, they are fully insulated.

All the grounds on the harnesses are now installed and I still get heat on the ground of the fuel gauge.

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Old 07-10-2018, 03:11 PM
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Did you say that you bench tested the fuel gauge?
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Old 07-10-2018, 04:02 PM
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Originally Posted by Peterbuilt View Post
Did you say that you bench tested the fuel gauge?
I don't know about bench testing but I did inspect the posts and all the insulators were intact around the posts and the ground was tight. No continuity between the ground and the other two posts either.

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Old 07-10-2018, 04:23 PM
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Originally Posted by MBrianB View Post
I don't know about bench testing but I did inspect the posts and all the insulators were intact around the posts and the ground was tight. No continuity between the ground and the other two posts either.
If you want to bench test the fuel gauge:
12 volts to the bottom terminal
Ground to the 3 o'clock terminal
top wire to one side of a flasher and then out the other terminal to the same ground.



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Old 07-10-2018, 04:50 PM
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Originally Posted by Peterbuilt View Post
If you want to bench test the fuel gauge:
12 volts to the bottom terminal
Ground to the 3 o'clock terminal
top wire to one side of a flasher and then out the other terminal to the same ground.
ok I'll try that. The entire gauge panel was rebuilt and I'm the first to install it.
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Old 07-12-2018, 07:08 PM
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Originally Posted by MBrianB View Post


ok I'll try that. The entire gauge panel was rebuilt and I'm the first to install it.
Bench test results:
Gauge goes to 1/8 past half.

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Old 07-13-2018, 03:38 PM
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Originally Posted by MBrianB View Post
Bench test results:
Gauge goes to 1/8 past half.
If the gauge works on the bench then what caused it to overheat when installed?
Is your center dash bezel cracked?
Do you have this BLACK ground wire connected?



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Old 07-13-2018, 03:42 PM
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All those grounds are landed. Dash lights work checked sender and it is grounded also.
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Old 07-13-2018, 03:54 PM
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You said that you did some work at the starter.
There is a thick black ground wire that should connect to a bell housing (or starter bolt) it's not on the battery solenoid terminal is it?
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Old 07-13-2018, 03:57 PM
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Just reinstalled it yesterday and ground is good there also.
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Old 07-13-2018, 03:59 PM
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Then we need some professional help!
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Old 07-13-2018, 04:04 PM
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MBrianB
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I will try the Wilcox procedure and see what I come up with. Could it be due to the tank being bone dry?
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