fuel level help
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Posting Guru
Joined: Jan 2003
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From: Munroe falls, Ohio
fuel level help
my gas gauge is quirky, it will go past the correct level by a quarter tank then come back down to rest at the right place even when the truck is not moving. I used a pot, and for the gauge to read full it needs 16 ohms and for empty 90 or so ohms. at the sending unit connector, the ivr is sending an irregular pulse, not perfect timing. on an analog meter it pulses a fast 7v with a few slower 8.5v mixed in.
so whats wrong?
so whats wrong?
Posting Guru
Joined: Jan 2000
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From: Cullman Alabama
fuel level help
When you used the Pot, did you check to see that the Guage went up to Full without a hitch?
When you looked at the sending unit. Did you disconnect the wire from the Dash guage? You should have. Read the sending unit output in Ohms.
It's always the sending unit though! Guage failure is so rare, even with humanoid intervention.
You can sometimes fix those sending units, but because it's "Sometimes" it's just better to buy a working replacment.
When you looked at the sending unit. Did you disconnect the wire from the Dash guage? You should have. Read the sending unit output in Ohms.
It's always the sending unit though! Guage failure is so rare, even with humanoid intervention.
You can sometimes fix those sending units, but because it's "Sometimes" it's just better to buy a working replacment.
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Posting Guru
Joined: Jan 2003
Posts: 1,412
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From: Munroe falls, Ohio
fuel level help
i disconected the connector at the fuel tank. clip two jumper cables, one to each female connector, to a pot. i had two pots one set to 10 ohms and one to 80 ohms. when i connected the 10 ohm pot the gauge went past full so i adjusted it to read excatly full which came to be 16 ohms. I connected the 80 ohm pot and the gauge moved past empty so i put it to excatly empty or 90 ohms.
at the same connector, the ivr was sending an irregular pulse mostly fast 7v with some slower 8.5v pulses.
what should the ivr be sending to the sending unit?
where could i buy a replacement?
at the same connector, the ivr was sending an irregular pulse mostly fast 7v with some slower 8.5v pulses.
what should the ivr be sending to the sending unit?
where could i buy a replacement?
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Joined: Jan 2001
Posts: 57,025
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From: Virginia
fuel level help
The ivr sends power to all the guages. So if it is bad, you will see all the guages vary together. I vote either a bad ground connection at the sending unit, or a bad sending unit.
Posting Guru
Joined: Jan 2000
Posts: 1,899
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From: Cullman Alabama
fuel level help
Did you ever check the Resistance across the tank sending unit? I see you used two pots to check the guage, but I didn't see where you checked to see what the sending unit actually said.
On getting a new one. I worked my Butt off getting one out of a wrecked truck. The fuel in it just reeked. Some bad smelling stuff in there, but the sending unit and the fuel filter were intact and working. That was the hardest $10 bucks I ever spent.
The ground on that front tank is on the frame, right close to the tank wiring. But it's not the problem, it's the sending unit.
On getting a new one. I worked my Butt off getting one out of a wrecked truck. The fuel in it just reeked. Some bad smelling stuff in there, but the sending unit and the fuel filter were intact and working. That was the hardest $10 bucks I ever spent.
The ground on that front tank is on the frame, right close to the tank wiring. But it's not the problem, it's the sending unit.
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