Notices
1967 - 1972 F-100 & Larger F-Series Trucks Discuss the Bumpsides Ford Truck

Sending Unit Accuracy ?

Thread Tools
 
Search this Thread
 
Old Feb 9, 2013 | 12:50 AM
  #1  
Redmanbob's Avatar
Redmanbob
Thread Starter
|
Logistics Pro
15 Year Member
Joined: Oct 2005
Posts: 3,785
Likes: 4
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 ?
 
Reply
Old Feb 9, 2013 | 06:27 AM
  #2  
NumberDummy's Avatar
NumberDummy
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 787
From: Simi Valley, CA
Club FTE Gold Member
Originally Posted by Redmanbob
The 71 in-cab tank switch (dash gauge) 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?
1970/72 F100/750: In-Cab fuel tank has a 19.5 gallon capacity except 1971/72 F100's sold new in CA ~ this tank has a 18.5 gallon capacity.

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. < <
 
Reply
Old Feb 9, 2013 | 06:28 AM
  #3  
jowilker's Avatar
jowilker
Fleet Owner
25 Year Member
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
Club FTE Silver Member

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
 
Reply
Old Feb 9, 2013 | 06:45 AM
  #4  
NumberDummy's Avatar
NumberDummy
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 787
From: Simi Valley, CA
Club FTE Gold Member
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.
 
Reply
Old Feb 9, 2013 | 07:15 AM
  #5  
jowilker's Avatar
jowilker
Fleet Owner
25 Year Member
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
Club FTE Silver Member

Thanks Bill, That is not the case here, mine has been pretty consistent 10 years or longer. I have just dealt with it.


John
 
Reply
Old Feb 10, 2013 | 09:15 PM
  #6  
Redmanbob's Avatar
Redmanbob
Thread Starter
|
Logistics Pro
15 Year Member
Joined: Oct 2005
Posts: 3,785
Likes: 4
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 ...
 
Reply
Old Feb 10, 2013 | 09:35 PM
  #7  
smokenchoken's Avatar
smokenchoken
Fleet Mechanic
10 Year Member
Joined: May 2012
Posts: 1,724
Likes: 1
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
 
Reply
Old Feb 11, 2013 | 03:44 AM
  #8  
NumberDummy's Avatar
NumberDummy
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 787
From: Simi Valley, CA
Club FTE Gold Member
Originally Posted by Redmanbob
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 ...
In-Cab fuel tank sender does not have a pickup tube. It's separate and threads into the top of the tank adjacent to the sending unit.
 
Reply
FTE Stories

Ford Trucks for Ford Truck Enthusiasts

story-0

Every 2026 Ford Engine Explained

 Brett Foote
story-1

10 Ugly Ford Trucks That We Still Kinda Love

 Joe Kucinski
story-2

10 Things Every Truck Owner NEEDS (2026 Edition)

 Michael S. Palmer
story-3

Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

 Verdad Gallardo
story-4

Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

 Joe Kucinski
story-5

2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

 Brett Foote
story-6

Top 10 Ford Truck Tragedies

 Joe Kucinski
story-7

AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

 Brett Foote
story-8

Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

 Michael S. Palmer
story-9

Ford's 2001 Explorer Sportsman Concept Looks For a New Home

 Verdad Gallardo
Old Feb 11, 2013 | 08:32 PM
  #9  
Redmanbob's Avatar
Redmanbob
Thread Starter
|
Logistics Pro
15 Year Member
Joined: Oct 2005
Posts: 3,785
Likes: 4
From: Mddl A MexCans
Originally Posted by NumberDummy
In-Cab fuel tank sender does not have a pickup tube. It's separate and threads into the top of the tank adjacent to the sending unit.
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.
 
Reply
Old Feb 11, 2013 | 10:26 PM
  #10  
The Masked Rider's Avatar
The Masked Rider
Posting Guru
Joined: Jan 2011
Posts: 1,670
Likes: 8
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.
 
Reply
Old Feb 13, 2013 | 10:38 PM
  #11  
Redmanbob's Avatar
Redmanbob
Thread Starter
|
Logistics Pro
15 Year Member
Joined: Oct 2005
Posts: 3,785
Likes: 4
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 ?
 
Reply
Old Feb 14, 2013 | 12:11 AM
  #12  
gabbagabbawill's Avatar
gabbagabbawill
Junior User
Joined: Jan 2013
Posts: 50
Likes: 0
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.
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Pitcrw6
1973 - 1979 F-100 & Larger F-Series Trucks
4
Apr 2, 2014 04:36 PM
daddy hadday
1961 - 1966 F-100 & Larger F-Series Trucks
7
Aug 12, 2011 12:32 PM
davewatson
Large Truck
2
Aug 10, 2011 08:21 PM
stil190
1961 - 1966 F-100 & Larger F-Series Trucks
5
Aug 12, 2010 11:41 PM
soooop
1961 - 1966 F-100 & Larger F-Series Trucks
21
Mar 14, 2010 02:05 PM




All times are GMT -5. The time now is 05:46 PM.

story-0
Every 2026 Ford Engine Explained

Here's everything you need to know about every Ford engine available for the 2026 model year.

By Brett Foote | 2026-06-05 12:58:01


VIEW MORE
story-1
10 Ugly Ford Trucks That We Still Kinda Love

Slideshow: 10 ugly Ford trucks that we still kinda love.

By Joe Kucinski | 2026-06-03 09:51:16


VIEW MORE
story-2
10 Things Every Truck Owner NEEDS (2026 Edition)

Slideshow: the best gifts for dads & grads

By Michael S. Palmer | 2026-06-03 15:43:58


VIEW MORE
story-3
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.

By Verdad Gallardo | 2026-06-03 11:38:36


VIEW MORE
story-4
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Slideshow: 10 most expensive Ford trucks ever sold on Bring a Trailer.

By Joe Kucinski | 2026-05-27 16:24:34


VIEW MORE
story-5
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Here's everything that has changed for the latest model year.

By Brett Foote | 2026-05-27 16:17:28


VIEW MORE
story-6
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

By Joe Kucinski | 2026-05-18 19:34:33


VIEW MORE
story-7
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

And it might be even better than that.

By Brett Foote | 2026-05-18 19:26:42


VIEW MORE
story-8
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

Slideshow: Does lowering an F-150 Lobo RUIN the ride quality?

By Michael S. Palmer | 2026-05-18 19:20:37


VIEW MORE
story-9
Ford's 2001 Explorer Sportsman Concept Looks For a New Home

Slideshow: Ford's bizarre fishing-themed Explorer concept has resurfaced after spending decades largely forgotten.

By Verdad Gallardo | 2026-05-12 18:07:46


VIEW MORE