Fuel Level Sensor Investigation

ixtlan

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Ok since I am having issues with my Fuel Level sensors I decided I needed to see what they were and how they were put together.
Ford claims that buildup of Sulfur on the contacts is causing the FLI errors and the erratic gauge issues.
So to do my own investigation I jumped in to see what I could see.
Here we go:
First remove the rear seat lower half and set it aside.
And remove the plastic cover over the tank sensor.
Just pulls off.
Here is what you see:
Sender1.jpg


Next step is to unplug the electrical connector and remove the lock ring from the sender unit. Just use a drift and tap the lockring CCW to unlock it and remove it.
Sender2.jpg


The Sender assembly is spring loaded and may pop up slightly when the ring comes off. If not just wiggle it a little to free it from the o-ring seal between the sender and the tank. There is a fuel line (Crossover tube) connected to the assembly. This will need to removed before you can pull the sender out of the tank. To remove it push in on the green tab while pulling on the fuel tube connector. Push Hard to get it to release. Here is a picture with the tube released and sender assy out of the tank so you can see it better.
Sender3.jpg



After the tube is disconnected just carefully maneuver the sender out of the tank. Be careful of the Float attached to it.

Sender4.jpg


So here is the assembly out of the car.
The Sensor is the white plastic item on the assembly.

Sender5.jpg


To remove the sender simply remove the small screw at the bottom and gently slide the assembly up off the sender assembly. You will see how it comes off no problem.

This is what you will get:
Sender6.jpg


Next on to what make this tick.
We need to spread some plastic ears slightly to get the cover/coil to separate from the mount plate it is on. Be careful because they can break very easily.
The Float and cover come off and we can see how this thing works:
(Sorry the picture isnt so great)
Sender7.jpg


The float is connected to a plastic part that holds a contact against the variable potentiometer (Coil). As the Float rises and falls it varies the resistance on the coil.
You can remove the float to disassemble the contact from the assembly. It is held together by ears like the body. Just tap the protruding shaft to unsnap it from the ears. Careful again as they can break really easy.
Here is the disassembled unit:
Sender8.jpg


Here is a poor picture of the moving contact:
Sender10.jpg

I took a pencil eraser and cleaned off the coils and the sprayed it down good with MAF cleaner.
Sender9.jpg


The coil seemed to have a lot of wear on it where the contact was riding on the coil. So I also slightly bent the contact so it touched on a different path.

Reassembly is just reverse of removal.
I put all back together and put it back in the tank.

Seems to be working so far. Time will tell for sure.
The Drivers side is the same setup but of course has all the pump components too.
I didn't remove it as my problem seems to be on the Full side of the tank level.

Pretty simple setup but not really reliable as history has shown so far.
Hopefully Ford improved the design and made it more robust.
But now we know how it works and what it looks like in there.

IMO the Sulfur claim could be bogus. I think it is wear that is causing the problems.


Good luck with yours and hope this helps someone out a bit.
 

Bizzyb0nes

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my gauges read all sorts of crazy after a week of owning mine....it'd throw a code for the passenger side sender asy....and after 4 trips to the dealer they determined it to actually be the drivers side.
 

scramblr

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Thanks for the write-up ixtlan. A month or so ago I was getting ready to buy a new sender (it's not expensive) due to zero readings on the gas gauge. However, I first wanted to measure the current going out of the sender. When I took the seat off, there was a lot of dirt on top of everything. I cleaned everything and got good electric readings. Buttoned it all up and has worked perfect since. In my case it looks like it may have come loose and/or got dirt in the connection.

That being said, if it happens again, I now have a great write-up to fix it.
 

LSlayer

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Great write up, I'll be doing mine this weekend. Am I correct in assuming that circuit A is the drivers side sensor?
 

ixtlan

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Great write up, I'll be doing mine this weekend. Am I correct in assuming that circuit A is the drivers side sensor?

No.
Circuit A refers to the full system.
The senders gets the signal as a combined reading (Circuit A) so it could be either sensor.
It is best to change both at the same time.
Or ohm both to determine the bad sensor.
The readings should be from empty to full 15-E to 160-F ohms and should smoothly rise through the range.
If both are good then it may be the Fuel Pump module (Unlikely as it is pretty reliable).
 

G.T

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how's this DIY fix holding on?
i have a car with the exact symptoms and i'm contemplating a DIY fix rather than replacing the sender unit, if this would indeed solve the issue

p.s: the issue with the FLI started all of a sudden, where the fuel level gauge sometimes stays on full regardless how long the car has been driven till you take a hard turn and it suddenly drops, sometimes to 0
 

GIG4FUN

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is the fuel level sensor on passenger side and pump on the drivers side?

Is there only one sensor (and that being the pass. side one)?

I bought a pump assy to do the TSB thing about the sulfer build up code.
I see float etc on the fuel pump I bought.... (thus my curiousity).

I bought the pump to fix the erratic gage and high current code on my wifes '05. (Maybe I need something else?) as in ... I got the wrong thing and wrong side on the tank et cetera!
 

G.T

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There are two level sensors, one on each side
The driver side sensor is part of the pump assembly
The passenger side is a stand-alone sensor with a pickup line the feeds the pump on the other side to equalize the fuel level on both sides of the saddle
 

HOLYWD

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Mine wants to say its full when gassing up and pump stops pumping after like 6 gallas , even if its empty ?
But gauges read fine
 

TX_JC_GT

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My fuel gauge doesnt stop at full, it sometimes goes all the way past full, sometimes pointing straight down, my rpm gauge also has been acting up lately the other morning i was idling and it said i was turning zero rpms...any ideas why?
 

ixtlan

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Sounds more like the Stepper Motors are crapping out.
Do the needles stick sometimes with the key in ON?
They should all zero.
 

TX_JC_GT

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i wouldent say it sticks, because when the car is on the gauges still move...as i use more gas the fuel gauge still moves left, only it starts out pointing downward, its really weird i will try to post a picture this week...it almost seems to me like when the weather started cooling down this problem started to occur. i live in houston so it went from extremely hot to extremely cold within a month
 

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