Having a problem with the fuel gauge on a 2005 F-150 4x4 Lariat. I've never seen anything like this. When you fill the truck up with gas, the fuel gauge goes to empty and the low fuel light comes on. Sometime after driving it for hours the fuel gauge will start to read what might be close. Fill it back up and back to empty the gauge goes. Not sure if this has anything to do with it but the **** for the A/C don't work anymore. It just wants to blow out of the bottom by your feet. When you turn the **** to any other setting you can hear something under the dash making a noise like stripped gears but it still comes out by your feet no matter where you turn the ****. The truck is out of warranty because of miles.

 

I normally would tell you to find the sending unit wire, take it off the tank and ground it and then unground it, and if the gauge swept full scale when you did this, then the sending unit was bad. But I just looked at a 2005 diagram, and they don't ground the sending unit anymore, they send two wires back to the instrument cluster.

But if it's like the old trucks, 9 time out of 10, the problem is the sending unit. I would check the connections at the tank, but if they looked ok, I would go ahead and pull the unit from the tank. Make sure there is no fuel in the float, and you can put a ohmmeter on the sending unit, and see if it changes resistance smoothly when you move the float arm.

 

Have been experiencing a similar problem with my '07 Lariat F150 SCrew. Have just over 4,000 miles on it and the last two fill ups had the gauge showing about 1/4 tank for a while then eventually giving what appears to be an accurate reading.

Visited with my local dealer today and he told me that there have been issues with the 2005 and up model vehicles sending unit with the sulpher content in some of the gasoline. He recommended that I put a bottle of Chevron Techron Concentrate Plus fuel system cleaner in the tank.

I went to local Pep Boys and looked at all the fuel system cleaners but only the one he mentioned stated that it would help protect the sensors against the sulphers that are in the fuel.

The local dealer is a good friend and stated that this was the easiest way of dealing with the problem. He said that several vehicles had been brought in within the last few weeks with this problem. I wonder if we are all using the same local service station in the small community I live in. It is a national brand but who knows what is going in the ground?

Hope this information helps.

 

Thanks Austin. I'am going to try that. Sounds easier then dropping that fuel tank.. I got the heater/AC **** fixed. It's been really hot here in Memphis and the temperture control has lived in the cold position for a long time. I just fooling around turned it to heat, put it in the middle for awhile and them to cold. The control **** for outlets started to work agian. Why I don't know. I know what to do if it ever does it agian. Agian thank you...

 

Let me know if this works for you Vaporloc, I just got this information on the day I posted to you and have not had the opportunity to put the fuel system cleaner in my tank yet. It will probably not be an "instant" fix but may take a few miles of operation. The real way of seeing if it works will be with the next fill-up.

The information on the bottle indicates that it should protect your sending unit for several thousand miles. Sure hope so at the cost of a bottle of this cleaner.

 

I guess someone's "better idea" didn't work to well? The old way of doing it worked for years and years. I wonder why they had to change the sending unit configuration? Maybe he had stock in the "special fuel additive" company.

 

Franklin 2. I know this is not the proper place for this but why do you call yourself Franklin 2. Do you collect Franklin automobiles? Just curious..

 

My last name is Franklin, and the 2 is because long long ago, something happened when I registered as Franklin, and I had to put the 2 after it and re-register. Not a cliff hanger story is it.

 

Austin; The Chevron fuel cleaner seems to have cured the problem. I bought 2 bottles (they are pretty proud of that stuff $7.99 a bottle) dumped the first one in with the guage showing between 1/2 and 3/4 of a tank. The bottles instructions said 1 bottle to 12 gallons. I dumped the 2nd. bottle in when the guage showed between 1/4 and 1/2. I drove it as usual till it needed gas. When I filled the tank, gauge went to full like it should. Thanks bunches Austin, I sure didn't want to drop that tank.. So tell your buddy at the dealer it does work. Once agian Thanks Vapor..

 

Glad to hear it worked for you Vaporloc, my dealer told me it had worked for other people also. I bought one of the bottles that treats 20 gallons and am waiting on my 37 gal. tank to get to about 1/2 full before adding. I don't drive my F150 every day so it sometimes takes me a little time to get some miles on the unit.

Austin