fuel guage
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Senior User
Joined: Mar 2005
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From: indiana
fuel guage
i just replaced my gas tank with a new one that was in my previous 79 so i now the guage used to work. well i put in my new 79 and the guage reads nothn. i checked the wiring where it plugs into the tank.. is there anyway i rewire the whole thing. any ideas?
New User
Joined: Jan 2008
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Test the harness first with a multi-meter for a PULSING 5 volts.
If that pulsing voltage isn't there ...the gauge won't read.
The other way is to figure it out is .....ground out the S/U connection and then go turn the ignition Key to RUN position.....check the fuel gauge ...if the gauge pins to the high side, the circuit has power.
If that pulsing voltage isn't there ...the gauge won't read.
The other way is to figure it out is .....ground out the S/U connection and then go turn the ignition Key to RUN position.....check the fuel gauge ...if the gauge pins to the high side, the circuit has power.
Postmaster
Joined: Apr 2000
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From: SD
Usually the problem is cracked/broken wires or bad ground. If the wire along the frame looks cracked - replace it. Be sure to solder all splices and clean the ground point with sandpaper and coat with dielectric grease.
Marty
Marty
Senior User
Joined: Feb 2006
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I worked on a Ford fuel gauge this weekend. We couldn't locate the problem because all the electrical worked fine at the guage and at the sending unit. After the unit had been out of the tank 10-15 minutes, we noticed the float was still wet. After close inspection, there was a hairline crack in it. It would take on fuel and drop to the bottom. A new float solved the problem.
At least it's another place to look in your case.
At least it's another place to look in your case.
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New User
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Thanks for the reminder
although I have that condition listed in my "Guage reads empty" check list.
In this case the OP replaced the tank which would involve removing the SU and thus if it had fuel in it would be noticed right away.
Although there is the coincedence factor and that float may have filled up when he put gas in the new tank
although I have that condition listed in my "Guage reads empty" check list.
In this case the OP replaced the tank which would involve removing the SU and thus if it had fuel in it would be noticed right away.
Although there is the coincedence factor and that float may have filled up when he put gas in the new tank
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Senior User
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I have no power at sending unit, but there is power at the guage. But haven't found power coming out of the instrument cluster. Which color is coming out of the cluster plug? I know the wire going to the sending unit needs replaced too. The ground wire isn't in to good of shaped but it grounds fine. I will replace it when I replace the power wire coming back. Then I will check to see if the su works or not. Thanks
New User
Joined: Jan 2008
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What's the power at the gauge ?
Check the instrument cluster voltage regulator for a pulsing 5 volts.
http://www.clubfte.com/users/mil1ion...strations.html
Check the instrument cluster voltage regulator for a pulsing 5 volts.
http://www.clubfte.com/users/mil1ion...strations.html
Senior User
Joined: Feb 2006
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will the power wire at the sending unit have a pulsing 5 volts? I plan on checking it tonight if i get a chance since i have replaced the power wire to the sending unit and replaced the ground wire with good ground. Or is the votlage regulator the little box thats attached to backside of the cluster that has circut running to the fuel guage?
New User
Joined: Jan 2008
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Yes 5v pulsing at the sending unit.
Make sure you have a very good ground before you test it though.
Use a jumper wire and go to a point where you know it a good clean ground.
I common problem for those who say they don't get a signal is that they are trying to ground to a rusty frame.
Make sure you have a very good ground before you test it though.
Use a jumper wire and go to a point where you know it a good clean ground.
I common problem for those who say they don't get a signal is that they are trying to ground to a rusty frame.
Senior User
Joined: Feb 2006
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I checked it this weekend and with new jumper wire to the neg battery terminal to the power wire of sending unit has 0.01 volts pulsating. I have the same using the ground wire to power wire. Do I need to try it through the sending unit or not? Or where do I need to look for a new problem? Thanks
Ty
Ty