crazy gas gauge
Race Director
Joined: Nov 2006
Posts: 13,065
Likes: 7,678
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
Sending unit is easy to check with an ohm meter. But the swinging sounds like a bad guage.
The connector for the sending unit is in the left hand side quarter panel. Unplug it. Connect your ohm meter across it. Have your helper raise and lower the float arm using a bent coat-hanger through the filler hole. It's a zero to 90 ohm sender. Pretty standard fare.
The connector for the sending unit is in the left hand side quarter panel. Unplug it. Connect your ohm meter across it. Have your helper raise and lower the float arm using a bent coat-hanger through the filler hole. It's a zero to 90 ohm sender. Pretty standard fare.
Team Owner
Joined: Aug 2000
Posts: 21,415
Likes: 451
From: Massillon,Ohio USA
2020 C3 of the Year Finalist - Unmodified
Cruise-In VI Veteran
St. Jude Donor '08-'09-'10-'11-'12
...one of the easiest & cheapest things to do for this is to check and clean the black ground wire going to the frame back in the left rear corner, at least on a '68. This fixed my swinging gas gauge instantly.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,112
From: Crossville TN
Most likely bad electrical connection (corrosion) on terminals under rear of car. Check the ground connection first. Remove, de-rust, wipe clean, reassemble and test the result. If that fixes it, coat the connection with sealant that will keep water/air out.
Instructor
Joined: May 2023
Posts: 146
Likes: 54
From: Finger Lakes, NYS
I had this problem 2 years ago, shortly after buying my 2014 Z51. Techron treatment did the trick.....for a while. When it failed again Techron didn't work. The right fuel tank gauge failed. My extended warranty paid the $3000 bill to put in the new sensor which was mechanically stuck. This past November it happened again. This time the left side sensor failed and the left side fuel pump had a low pressure signal. Once again my warranty paid the $3200 bill. So your fix may be costly. Since most of the cost is labor to drop the whole rear sub-assembly, change both sides at once! Good luck.
Ken
Ken
Burning Brakes
Joined: Jul 2009
Posts: 910
Likes: 47
From: Kansas City MO
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