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#51 | |
Registered User
Join Date: Aug 2016
Location: Idaho
Posts: 42
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Re: Fuel Gauge
Quote:
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_____________________________________________ 1972 C10 - SWB /383 stroker/Th400/3.73/vintage air |
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#52 |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
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Re: Fuel Gauge
34.7 after 10 gallons and 25 miles. Maybe my tan wire is adding resistance along the line?
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'72 K5, known as 'the Fox.' |
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#53 |
Registered User
Join Date: Aug 2016
Location: Idaho
Posts: 42
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Re: Fuel Gauge
So virtually no change after adding 10 gallons of gas. Are you measuring at the tank/sending unit, or at the fuse box with tan wire disconnected and measuring wire back towards tank?
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_____________________________________________ 1972 C10 - SWB /383 stroker/Th400/3.73/vintage air |
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#54 |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
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Re: Fuel Gauge
At the sending unit, tan wire still attached, and grounding stud where jumper from the flange is connected to the frame.
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'72 K5, known as 'the Fox.' |
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#55 | |
Registered User
Join Date: Aug 2016
Location: Idaho
Posts: 42
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Re: Fuel Gauge
Quote:
If it's easier, you can measure at the fuse box by disconnecting the tan wire from the fuel terminal (located at the top of the box). Measure the end of the wire (which goes back to the tank) and the other lead to a known good ground. This is all to confirm what we already suspect, that the sending unit is bad.
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_____________________________________________ 1972 C10 - SWB /383 stroker/Th400/3.73/vintage air |
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#56 |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
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Re: Fuel Gauge
That explains why the 2 readings were so similar.
With the tan wire disconnected, I get 133 Ohms. Obviously, I shouldn't get more than 99, and that should be on a full tank. My guess is corrosion between the resistor and the terminal on top of the sender. I wonder why the needle movement the other day with sloshing gas...? I'm going to order a new sender this week, so next time I drop the tank I can either fix mine or replace it and be done!
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'72 K5, known as 'the Fox.' |
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#57 | |
Registered User
Join Date: Aug 2016
Location: Idaho
Posts: 42
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Re: Fuel Gauge
Quote:
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_____________________________________________ 1972 C10 - SWB /383 stroker/Th400/3.73/vintage air |
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#58 |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
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Re: Fuel Gauge
Ordered the new sender. Maybe next weekend.
Tanked up this morning; ohmed out at 124.6
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'72 K5, known as 'the Fox.' |
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#59 |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
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Re: Fuel Gauge
Wrong part arrived. Waiting on new sender.
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'72 K5, known as 'the Fox.' |
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#60 |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
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Re: Fuel Gauge
Well, Brother's didn't have the right sender for my Aero tank. I'd expect LMC and the like not to have them either. Aero wants $78...
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'72 K5, known as 'the Fox.' |
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#61 |
Registered User
Join Date: Dec 2003
Location: Houston, TX
Posts: 734
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Re: Fuel Gauge
Gauge works now, for about the last 5-10 gallons. Still looking for the right sender for my Aero tank. Aero wants $78 plus shipping!
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'72 K5, known as 'the Fox.' |
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#62 |
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Join Date: Aug 2018
Location: BARRIE, Ontario
Posts: 118
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Re: Fuel Gauge
Guys I've been reading over your conversation and I know its been awhile, but I just got about 1.5 months ago 69 c10 and the fuel gauge always sits on empty, when I disconnect the ground form sending unit with key on it goes to 3 o'clock, ground it to gas tank it goes back to empty. My tank is always on full and the needle just does not move at all, so my question is this is a float problem, sending unit problem or a grounding problem. Any help would be greatly appreciated form mister.freeze and bstock1962 on this issue and anyone else please. In the picture uploaded i am driving with a full tank.
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1969 'Matte Blackie' Oshawa Built Chevy C10 Stepside 307 three-on-the-tree |
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#63 |
Senior Member
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Location: Cypress, TX
Posts: 3,704
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Re: Fuel Gauge
Yes sounds like the float. Go ahead and remove the sending unit and see if the float is off the arm or full of gas. See this thread. http://67-72chevytrucks.com/vboard/s...d.php?t=666161
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#64 | |
Registered User
Join Date: Aug 2018
Location: BARRIE, Ontario
Posts: 118
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Re: Fuel Gauge
Quote:
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1969 'Matte Blackie' Oshawa Built Chevy C10 Stepside 307 three-on-the-tree |
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#65 |
Msgt USAF Ret
![]() ![]() Join Date: Jan 2005
Location: Kalamazoo, Michigan
Posts: 8,714
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Re: Fuel Gauge
Got mine from these guys and I/m very happy with it.
https://www.partsgeek.com/catalog/19...ding_unit.html If you have a v-8 they will send you the one with a 3/8ths line which is correct but if you had a six cylinder you probably have a 5/16ths line. I had a six originally and the v-8 ran fine but I changed all the lines to 3/8ths. I ohmed the sender and it was right on the money, 0 empty and 90 full. $34 bucks and free shipping.
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VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative. |
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#66 | |
Registered User
Join Date: Aug 2018
Location: BARRIE, Ontario
Posts: 118
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Re: Fuel Gauge
Quote:
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1969 'Matte Blackie' Oshawa Built Chevy C10 Stepside 307 three-on-the-tree |
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#67 | |
Registered User
Join Date: Jun 2012
Location: Clearwater Beach Florida
Posts: 872
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Re: Fuel Gauge
Quote:
I'm going to chime back in because i never got mine working either. I just left it alone for a while lol I did replace my sending unit, mine is stuck on 3/4. The wires are hooked up correctly but I'm not getting anything where should I check? Is there a way to confirm that the guage is working correctly? |
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#68 | |
Senior Member
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Location: Cypress, TX
Posts: 3,704
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Re: Fuel Gauge
Quote:
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#69 |
Registered User
Join Date: Nov 2017
Location: Leeds west yorkshire
Posts: 307
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Re: Fuel Gauge
I gave my fuel sender wire a quick touch to earth, this makes the fuel gauge go to full. At least then you will know the gauge works
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#70 |
Registered User
Join Date: Nov 2017
Location: Leeds west yorkshire
Posts: 307
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Re: Fuel Gauge
Looks like a sender unit out job, ready for some tests
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#71 |
Registered User
Join Date: Jun 2012
Location: Clearwater Beach Florida
Posts: 872
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Re: Fuel Gauge
Extending this with another question. I replaced my sending unit. Guage has never worked. I get no power at the fuse box at the tan wire with power on or off. Grounding the fuse box tan wire does nothing at the fuse box. I attached a wire from power to the fuse box tan wire and the guage goes full? Where could the problem be? Thanks
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#72 | |
Msgt USAF Ret
![]() ![]() Join Date: Jan 2005
Location: Kalamazoo, Michigan
Posts: 8,714
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Re: Fuel Gauge
Quote:
I believe the fuel gauge will go to empty if you ground the sender wire and past full if you just disconnect the sender wire.
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VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative. |
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#73 | |
Msgt USAF Ret
![]() ![]() Join Date: Jan 2005
Location: Kalamazoo, Michigan
Posts: 8,714
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Re: Fuel Gauge
Quote:
The tan wire at the fuse panel is just a junction point for the sending unit wire to connect to the gauge. You should read 12 volts there if you have power to the gauge even though it has nothing connected. When you jump it to ground you will get current flow through the gauge to ground with no resistance which simulates an empty fuel tank. Remember the sender range is 0hms empty, and 90 ohms full. When you put power on the tan wire you are back feeding the gauge and it is reading through the gauge resistor to the gauge ground which deflects the needle to full. You need to concentrate on why you aren't getting 12 volts to your gauge resistor on the right hand terminal. The power for the fuel gauge also powers the brake warning light. Try grounding the brown wire on the proportioning valve and see if the brake warning light comes on. the temperature gauge also gets power from the gas gauge but it may not move unless the coolant heats up. If it has power you could ground the temp sender wire on the engine and the temp gauge should go full hot. What ever you do, do not put any power on the wire that goes to the sending unit into the tank. The resistor on the sender might glow and heat up enough to ignite the fumes in the tank. NOT GOOD.
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VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative. |
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#74 | |
Registered User
Join Date: Jun 2012
Location: Clearwater Beach Florida
Posts: 872
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Re: Fuel Gauge
Quote:
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