You probably have to bite the bullet and get the new assembly from ford and try that first. I would believe its the cause of your problems but unless you get a used one, or possibly an even better a deal on one from ebay, like I found fitting my application, its pricey from any ford source.

 

Yes, my trucks are diesels...but the tanks are the same for both gasoline and diesel. The pickup/sender assemblies can be modified just the same...both have the sending units, stainless tubing, and some wiring. The difference is the fuel pumps...the gasolines are sometimes part of the assemblies while the diesels are mounted on the frame below the drivers seat. The midship 38 gallon long bed tanks are 15.25" deep, the midship 29 gallon short bed tanks are 13.75" deep, and the 45 gallon aft axle tanks are 15.625" deep as taken from the bottom of the tank to the top of the flange where the pickup/sending unit mounts. Ford has a specific part number not only for each of these scenarios but also for the different wheel base and production dates...so you can see the endless part numbers that do not cross reference; but guess what, they do and they can be modified easily to work!

 

WAIT A MIN!!!!!

Proper reset is to use the headlight switch -- though hitting the brake should work.

Do not write off the thing just yet.

It takes a bit of time for the system to relearn the fuel tank level.

Give it at least 2 or 3 days, with lots of on and off cycles, to see if the gauge "resets".


If it fails --- do the reset again.


Don't give up hope without at least a week or two of testing.


In the mean time, fill the tank and keep a mileage log.

That is your "gauge" for now.

I think you have a electronic problem --- and at this time, I do not believe a new assembly is called for just yet!


If you replaced the sender unit.... you are still going to have to go through the relearn process.

 

Update...

Same condition driving around last night, still have no reading on gauge and the data loss error is there. I should also note that every time I hit the ignition to start, the gauge comes up to E for a second like it is "trying" to read but then drops back down along with the error message flashing.

More strangeness this morning on my way to the carpool lot. As I coasted into the lot it died as I came to a stop. Truck has NEVER done that. It fired up and I backed into the stall. (Evidently my "Now WTF is up now???" words convinced it to start...)
Will see what happens on the way home.

Will fuel up and reset the computer again tonight. I know there is not much fuel in there (maybe 5 gal) because I have intentionally let is run low in anticipation of dropping the tank. The trip odometer still works so that will be my mileage log. Obviously the miles to empty does not work since the computer is clueless to fuel level.

Main reason for wanting to get this solved soon is because (lucky me again) my emmisions is due this month. Our state law says no emmisions test can pass with a CEL on. I've asked at a couple places that I am friendly with and there does not seem to be an exception for this. The test is all computerized and they have to plug into the OBDII port.

Thanks again for the help so far.

 

Whoa!

Check for this.

Did you change fuel filters?

Did you get a tank of crud as you got to the end of the tank?

You are in Utah --- it is cold there --- do you have water in the fuel that froze?

Do you use gas line antifreeze?

Did you check tank for water?

If all of the above are OK, and fuel pressure measured is good...

Then you have an intermittent failure condition...

Most likely you have corrosion in the wiring going into the fuel tank sender / fuel pump unit or somewhere along the line.

Check also for damage to wiring. from tank all the way back to harness.

That is the only thing that can easily explain simultaneous fuel delivery failure (verify with fuel pressure gauge) and an incorrect reading fuel gauge that fails intermittently.

A jumbled signal from corroded / intermittent connection would also trip the CEL.

I am almost at the point of willing to bet you that the fuel module is good... (pump and sender), but I want you to verify no water, crud, and filter and pressure good first.

 

No, have not been into the tank, and was trying to avoid that. So far have tried techron fuel cleaner (per the srvice bulletin) and the computer reset you suggested.
It does get cold here but the truck made it through the winter just fine. It is kept in a shop. Even in cold weather fuel antifreeze is not needed if you drive regularly and don't buy cheap gas. This may be an issue if I were diesel or it was put in storage for the winter and the water seperated out of the fuel. This problem showed up at least a month since it was driven in freezing temps. (I save all the road salt for the old Subaru.)
My PO461 trouble code and the message center error still point to something in the sender, circuit, or maybe in the dash,
Have checked all visible wiring but will take you advice and be more thorough. I have this feeling that I will end up pulling the pumpa assy and checking it out. Will replace filter and do the crud survey then.

Also, some driving after work still has the fuel level error and guage below E. At least the CEL is out since the computer reset. If I'm lucky it will stay out long enough to get emissions done, then I can have more time to get to the bottom of this.

 

I have an '08 and had the fuel pump fail, none of the auto parts had it so I had to pay $500.00 from ford for it, it is the sending unit and the pump all together. There was a problem around here with a high sulfer content in the fuel and it caused sending units to fail and shell picked up the cost of the repairs for the affected vehicles. Droppind the tank is not too hard, make sure you run as much fuel out of it as you can. Put the truck on some jack stands to give yourself a little hieght. First you disconnect the filler tube hose and the vent hose. Then you loosen the straps and lower the tank a little with a floor jack. Go under the truck from the passenger side and unhook the quick connects you may want to pick up the tool at the auto parts it is only a few dollars. Then unhook the wiring harness. If you dont want to take the tank completely out you can go from the driver's side and lean the tank over and you can access it there but it would be easier to remove the tank I have done it both ways. Take a hammer and screwdriver and loosen the locking ring by unscrewing it about a half turn, you will see it pop loose. The fuel pump assy. should lift right out. When you install the new pump make sure the pickup sock does not fold under the assy. and get blocked, and make sure the internal wiring harness does not go in front of the float and prevent it from coming up, you have to rotate the assy. when you install it. Make sure the rubber o-ring seal is properly seated when you re-install the locking ring or it will leak or damage the seal, you can put some grease on the o-ring if you like to prevent it from binding when you twist the assy. in. Of course look for trash in the tank before you re-install. If you have a plastic tank like I do you want to put a 2x6 or a 1 by or some thing between the tank and jack so the tank will not break in the middle from the pressure of lifting it. When you raise the tank back up make sure the vent hose and filler neck hose with hose clamps in place is placed over the frame because it will fold out of the way and you cannot get to it with the tank up. It is a pain is the *** to do the job but it only takes about an hour and is not that hard if you are patient. Putting the truck up as high as you can before hand will make the job a lot easier. Also if you have an impact wrench it is way easier to work the strap bolts when raising or lowering the tank. You will have to get to both sides of the tank so do not lean the truck to one side when you lift it. Just bite the bullet and buy the whole assy. and be done with it, the sending unit is probably bad. By the way, you may have to bend the float wire and adjust it you may want to check the travel when you put it in. Good luck.

 

p.s. I still have the old pump assy., the pump was bad but the sending unit was still good, you are welcome to it if you want it if it will fit your year truck. Just let me know and I will mail it to you, I think you can just swap the pump if it is the same assy. you take, I have the 38 gal. tank. Get the part number from ford for your application and I will check it against the one I have. It may save you $500.00.

 

Wasn't that part covered under the 36month or 5 year emissions warranty?

 

Yes, but the dealer replaced it twice and f'd it up and when it failed again they refused to replace it again because I have a fuel transfer tank even though it is not hooked into the factory wiring harness. Besides I use the truck for work and I can't have it tied up at the dealer for days at a time.

 

Yes Bayou, I would definately be interested in that. I understand the sending unit bolts onto the assy. This would be a great way to rule out the sending unit...or fix it!!!
May just need to bend the float arm to approximate my tank dimensions since I have the smaller tank. Is yours an aft or mid tank? Send me a PM and we'll work something out.

Thanks!!

 

Just get the part number and see if it will work, you can just have it for free.

 

Got the pump and sender removed today,
P/n on the unit was 5C3U-9H307 AF

I've isolated it to the sender or the wiring.

Before I pulled it out of the tank I checked for resistance at the connector and got some though two of the pins. Didn't pay much attention because I didn't know where the wires were going and I knew I was pulling everything out tof the tank anyway.

With everything on the bech I could not get resitance or any continuity at first so I assumed the sensor was bad. Then started checking wires from the connector pins. Pink wire to sender frame was good but the yellow wire did not show good from connector pin down to where the wire goes into the sender unit. Started probing at the connectors in the middle of the yellow wire and after a few tries suddenly got continuity. It is possible that I was not making good probe contact but after I messed with the connectors I show good every time.
Not convinced that it is the wiring though because it could be somethin loose inside the board in the sensor and I also noticed there is some slop in the arm that rides against the curved resistor plate inside the sensor.

This could be the typical electrical thing where you take it apart and then it starts working but I still think there is someting wrong.
Would it make sense to replace that section of wire? Can I use any wire and solder? Do I have to shrink wrap the connectors like the stock setup or can I leave them bare?

Still interested in that sensor Bayou. It may be a good reassurance to put a known good sensor in so I don't have to do this again. Now that I know how it attaches to the pump housing I think I could make it fit if it is not just right.

 

That is exactly what mine did once I got it out of the tank...it just was not making continuity and after looking at the way the plat the sender sits on having junk all over it...must not be stainless like the tubing...I decided 10 plus years was long enough. Once I got the new one and plugged it in, bingo! I chaulked mine up to being hit in the back as I was hit by a Crown Vic doing 30 mph and not even hitting the brakes...totaled her car and bent my ball mount!

 

Danz

Appreciate you doing the work and reporting back.

Please let me know if it is really the wiring or the sensor....