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Sending Unit Accuracy ?
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Logistics Pro
Joined: Oct 2005
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From: Mddl A MexCans
Sending Unit Accuracy ?
The 71 main tank (cab mountd) switch shows that the fuel is a 1/8th tank and it's empty, and only takes about 10 gal fuel full. But reads 3/4 full ? Wondering what the issue is replace the sending unit or ?
capacity ?
capacity ?
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
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From: Simi Valley, CA
Take the sending unit out of the tank, remove the float and shake it to hear if gas is sloshing around inside.
The float (COAZ-9202-B ~ available from Ford) is made from two pieces of copper soldered together. Solder breaks down, gas seeps in, float settles to the bottom of the tank.
Both Blue Oval Truck Parts in Anaheim and Truck & Car Shop in Orange have a one piece brass replacement float.
If the sending unit (C1TZ-9275-K) is defective, the bad news is, it's obsolete.
The good news is, it's the same 1961/77 F100/750 = CARPENTER NOS OBSOLETE PARTS in Concord NC has 1,453 (!) = 800-476-9653.
> > Take the sending unit from your '66 and install it in your '71 and see what happens. < <
Fleet Owner
Joined: Jun 1999
Posts: 24,552
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From: Creedmoor, North Carolina
Bobby, I want to ride this one with you. I have some same issues, when my truck hits half you better start thinking gas, a little further down the road it hits 1/4 and you better be searching cause there aint much left.
I think there is a resistance issue as well as the moving lever. I didn't pay attention when I should have, so maybe there is a second chance.
John
I think there is a resistance issue as well as the moving lever. I didn't pay attention when I should have, so maybe there is a second chance.
John
Ford Parts Specialist
Joined: Nov 2006
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From: Simi Valley, CA
John, if the ICVR (Instrument Cluster Voltage Regulator) is defective, it also affects the temperature gauge.
When the little charmer begins to fail, the fuel and temp gauge needles do "the hula" swing wildly back/forth on their own.
The usual cause of a dash fuel gauge reading incorrectly, is the soldered together sending unit float (see post 2).
If so, whiz over to Durham and get one from your pal.
When the little charmer begins to fail, the fuel and temp gauge needles do "the hula" swing wildly back/forth on their own.
The usual cause of a dash fuel gauge reading incorrectly, is the soldered together sending unit float (see post 2).
If so, whiz over to Durham and get one from your pal.
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Logistics Pro
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From: Mddl A MexCans
Thanks for the intel Bill. I'll have a look, had to reprocess the issue a few times before it sync'd in the ole noggin. Leaking float, (low when full, fuel runs out and float retains fuel, then might bind on a composite. Or there is a pickup tube issue > Will review ...
Fleet Mechanic
Joined: May 2012
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From: peru kansas
mine never read over 3/4 tank full and they go waaaaayyyyy below E before i actually run out of gas but probably same problem
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Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
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From: Simi Valley, CA
Thanks for the intel Bill. I'll have a look, had to reprocess the issue a few times before it sync'd in the ole noggin. Leaking float, (low when full, fuel runs out and float retains fuel, then might bind on a composite.
Or there is a pickup tube issue > Will review ...
Or there is a pickup tube issue > Will review ...
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Logistics Pro
Joined: Oct 2005
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From: Mddl A MexCans
Well aware of that, only reason that ,makes sense to me for it to run out of fuel at .125 of a tank is if the tube has a hole in it, was cut short by a PO, is bent or something. I'll have to get the sending unit off and have a look. For now it is fine, I know what to expect from it.
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Joined: Jan 2011
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One of my trucks had a problem with NOT sucking all the fuel and it WAS a rusted hole a little way up the pickup tube.
You can also adjust the arm to read the correct amount of fuel. Next time your tank is almost empty, suck out all the fuel. Put 2 gals back in and play with bending the float arm untill it reads on the empty mark. THis will give ya 2 gals of gas to get your butt to a station. Since these motors get such crapppppy mileage - 2 gals isn't going to get ya far but at least you will know how much you have left.
You can also adjust the arm to read the correct amount of fuel. Next time your tank is almost empty, suck out all the fuel. Put 2 gals back in and play with bending the float arm untill it reads on the empty mark. THis will give ya 2 gals of gas to get your butt to a station. Since these motors get such crapppppy mileage - 2 gals isn't going to get ya far but at least you will know how much you have left.
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From: Mddl A MexCans
EDU: Follow up
Fuel pump was leaking at the crimped flange. NEW ****E!!
Well the sending unit float had no leaks. It did show signs of PO tampering on the high side tang stop not 90 deg. The arm took a decent bend to read full, and now it makes sense. I think, the float rested on the base reading .125 full with fuel to spare due to PO input. However, the tank still takes only 10 gal fuel before toping off. I tried to blow air into the pickup for a look, and the LPOR is at the base so it will disturb an attempt to find a pinhole unless easing air in in minute volume. How to check for pinholes in pickup tube advice ?
Well the sending unit float had no leaks. It did show signs of PO tampering on the high side tang stop not 90 deg. The arm took a decent bend to read full, and now it makes sense. I think, the float rested on the base reading .125 full with fuel to spare due to PO input. However, the tank still takes only 10 gal fuel before toping off. I tried to blow air into the pickup for a look, and the LPOR is at the base so it will disturb an attempt to find a pinhole unless easing air in in minute volume. How to check for pinholes in pickup tube advice ?
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Joined: Jan 2013
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From: Atlanta, GA
I removed my sending unit earlier tonight to repair it... it is incredibly easy to repair. I took it completely apart, cleaned it out, used a little bit of contact cleaner on the variable resistor wire and contact and some spray lube to keep it from oxidizing in the future.
I was able to bend the tang to get it to read ~70 ohms at the empty position and ~10 ohms in the full position.
A PO had replaced the float with a carb float, attached with some wire bended around it to hold it in place... I'm about to order a new float for it.
I was able to bend the tang to get it to read ~70 ohms at the empty position and ~10 ohms in the full position.
A PO had replaced the float with a carb float, attached with some wire bended around it to hold it in place... I'm about to order a new float for it.
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