Electrical contact cleaner vs fuel level sending unit

[Ifixyawata]

I'm closing in on an elusive EVAP leak code on the Expedition. I smoke tested it and found that it was leaking somewhere on the top of the tank. Waited for low fuel and dropped the tank and found it wisping out from around the pump/sending unit o-ring area.

I got a new o-ring at O'Reilly today and plan to replace it tomorrow if the weather allows. While I'm in there I want to try to clean the fuel level sensor, the gauge is not reading well when it's above 1/2 tank.

I know Techron is the go to when the sending unit is in the tank. Will something like DeoxIt work on the sending unit while it's out of the tank or are there better options?

 

[Rand]

replace it for 67?

Edit: its backordered.

Motorcraft AL1Z9A299A

Free Shipping - Motorcraft AL1Z9A299A with qualifying orders of $109. Shop Gauge Sending Units at Summit Racing.

www.summitracing.com

 

[Ifixyawata]

replace it for 67?

Edit: its backordered.

Motorcraft AL1Z9A299A

Free Shipping - Motorcraft AL1Z9A299A with qualifying orders of $109. Shop Gauge Sending Units at Summit Racing.

www.summitracing.com

I neglected to check to see that they were available separately... Always hear about how non-servicable the whole unit is.

Edit: Amazon has them in stock, but for $167, about $20 less than the whole unit, both Motorcraft.

I'm not opposed to dropping the tank yet again if cleaning it doesn't remedy the problem, I'll probably replace the whole unit at that time for "cheap insurance".

 

[BHopkins]

It's hard for me to imagine that a fuel level sensor, which has been immersed in fuel for years, would benefit from electrical cleaner. Gasoline is a pretty good solvent.

 

[Lubener]

I'm closing in on an elusive EVAP leak code on the Expedition. I smoke tested it and found that it was leaking somewhere on the top of the tank. Waited for low fuel and dropped the tank and found it wisping out from around the pump/sending unit o-ring area.

I got a new o-ring at O'Reilly today and plan to replace it tomorrow if the weather allows. While I'm in there I want to try to clean the fuel level sensor, the gauge is not reading well when it's above 1/2 tank.

I know Techron is the go to when the sending unit is in the tank. Will something like DeoxIt work on the sending unit while it's out of the tank or are there better options?

Replace the sending unit. Cleaner will only be temporary at best.

 

[KrisZ]

I'd replace it as well.
I highly doubt the electrical contacts would have corrosion, more like mechanical wear or the arm is bent or loose etc. Maybe those could be addressed, maybe not.

 

[Rand]

It's hard for me to imagine that a fuel level sensor, which has been immersed in fuel for years, would benefit from electrical cleaner. Gasoline is a pretty good solvent.

That was my thinking what is there to "clean" when its immersed in fuel.

 

[researcher]

That was my thinking what is there to "clean" when its immersed in fuel.

Unless we're talking about the electrical connections on the exterior of the sending unit.. Those are not in the tank.. just a thought..

 

[Astro14]

Replace it. It’s got worn contacts or some other mechanical problem that no amount of cleaning will solve.

 

[JohnnyG]

I think it will work and shouldn't hurt anything since it is designed to work in a much more active solvent.
One thing about gasoline that most don't know is that it CAN contain some caustic materials. Normally these aren't a problem, but depending on the car, the design of the sending unit, and the actual use of the car, (like always having it about half full), strange things can happen.
The caustic carryover can happen randomly at the refinery, and it's not easy to detect.
While you have that unit out, be sure to work the float many times with the cleaner applied, that should do the trick.

 

[Dave9]

It can get a coating of sulfur on it. Of course that's not the only possible reason why it could malfunction.



Techron Plus https://cglapps.chevron.com/sdspds/PDSDetailPage.aspx?docDataId=382377&docFormat=PDF

What you "might" be able to do while it's out, is if you can non-destructively pop the rotating (often black) piece off that the arm is attached to, I mean pop it off the frame piece it rotates on, then you have access to wipe the tracks with a paper towel (probably no solvent is needed), and use a needle/etc to gently bend a little more spring into the wiper fingers.

 

[Ifixyawata]

Thanks for the answers. I had a limited amount of time to have the vehicle out of service so I went ahead and dropped the tank last night with the intent of replacing the o-ring.

Once I got the tank off and into the garage the first thing I noticed was a "Carter" sticker on the top of the fuel pump hanger. Maybe an aftermarket replacement?

Second, the locking ring barely had any resistance when I tapped it off. Pulling the assembly up revealed that there was no o-ring installed. I pulled the pump assembly up and couldn't get it all the way out without forcing it but I did see that the original oring was laying in the bottom of the tank.

Reassembled it all andnso far everything is working but it will remain to be seen if the EVAP code goes away. I'm wondering why the fuel pump was replaced already at under 150k miles.