77 Gas Tank Sending Unit
Thread Starter
Le Mans Master
Joined: May 2008
Posts: 9,063
Likes: 2,736
2022 C3 of the Year Finalist - Modified
77 Gas Tank Sending Unit
My original sending unit was acting up, lots of bouncing around when tank not full. IS there a fix, OR buy new. THe prices for these units go from $90 for new "stainless"units on Ebay to over $235 at Volunteer Vette, and everywhere in between. Paul at Corvette Technicians tells me to be aware of cheap units that can cause fires!!!! Any recommedations or warnings?
Le Mans Master
Joined: Sep 2002
Posts: 5,236
Likes: 898
From: Myrtle Beach SC
It could very well be fixable if you have the patience. Willcox just published a video and pdf document that can assist with troubleshooting the fuel gauge sending unit. I was going to tackle it this weekend but did not went to deal with the winds and rain from hurr Sandy.
1977-82 Fuel Gauge Sending Unit
1977-82 Fuel Gauge Sending Unit
Safety Car
Joined: Mar 2005
Posts: 3,503
Likes: 2
From: Raleigh NC
My original sending unit was acting up, lots of bouncing around when tank not full. IS there a fix, OR buy new. THe prices for these units go from $90 for new "stainless"units on Ebay to over $235 at Volunteer Vette, and everywhere in between. Paul at Corvette Technicians tells me to be aware of cheap units that can cause fires!!!! Any recommedations or warnings?
Thread Starter
Le Mans Master
Joined: May 2008
Posts: 9,063
Likes: 2,736
2022 C3 of the Year Finalist - Modified
Gage
What dampens the needle in the gage, would it be a spring? I see the excellent troubleshooting link to Wilcox, which I will use to troubleshoot. But they mention nothing about the bouncing needle, only full or empty indications. Of course, it could be a loose connection. Just trying to gather all information.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
The most likely cause of your problem is a bad electrical connection....either the signal line going from tank to gauge or the ground line at the tank. Corrosion causes variable resistance in the 'bad' connection, causing fluctuating gauge readings.
If the gauge is reading anything at all, it's not likely to be at fault. Check wires/connections first (not behind the console, as that is usually a non-risk area for such problems); if you can't identify a problem with it, make simple tests of the full-range signals (Empty; Full readings) as described in the Willcox info. If gauge and wiring check out with the Willcox testing, the sending unit is most likely at fault.
If the gauge is reading anything at all, it's not likely to be at fault. Check wires/connections first (not behind the console, as that is usually a non-risk area for such problems); if you can't identify a problem with it, make simple tests of the full-range signals (Empty; Full readings) as described in the Willcox info. If gauge and wiring check out with the Willcox testing, the sending unit is most likely at fault.
Safety Car
Joined: Mar 2005
Posts: 3,503
Likes: 2
From: Raleigh NC
What dampens the needle in the gage, would it be a spring? I see the excellent troubleshooting link to Wilcox, which I will use to troubleshoot. But they mention nothing about the bouncing needle, only full or empty indications. Of course, it could be a loose connection. Just trying to gather all information.
Here's a diagram Willcox posted:
Last edited by PhotoVette1; Oct 29, 2012 at 08:49 PM.
