High sulfer content in the fuel is what does them in, it can corrode the shaft on the pump as well according to the ford dealer.

 

There was a rash of failures associated with high sulfur gas:

Excessive Sulfur Halts Gas Sales | North America > United States from AllBusiness.com

 

Bayou,
I'm still interested in that sender unit.
From my previous post here is the p/n that I currently have: 5C3U-9H307 AF
I stopped by Ford today and got the following numbers: pump assy 6C3Z-9H307-BA and the sender 6C3Z-9A299-B

Any of you electrical gurus know about in tank wiring? I want to replace section of my wiring prior to putting everything back in. I'm afraid there is some kind corrosion inside the wire that I can't see. Also want to drop a bit of solder on the connectors so they have no chance of moving around while sloshing about in the tank. Can I use regular copper wire and 60/40 solder or is their something better to use for a "in fuel" application. I'm guessing that I do not have to re-shrhrink wrap the connections since there is other exposed wires farther down the line anyway.

 

I would not try to repair electrical parts or circuits that will be submerged in the fuel tank, and kind of weak connection can cause a spark or heat enough to ignite the fuel, that is a really bad idea. I think if you have designs on doing something like that you would be better off just replacing the harness in whole with a new nos part.

 

OK, here is my "I fixed it" post.

Have now run a several tanks of gas through and everything seems fine.

I was convinced that there was something bad in the wiring inside the tank. I think it was the connectors that had somehow put a break in continuity but was afraid it could have been somewher in the wiring. Did not want to do this all again. So I put a bit of solder on the connectors to rule out that possibility. Soldered another wire from the board on the sender all the way up to the last connector. So I now have another path for current to flow if the original wiring was bad somewhere. Routed the wires so that everything clears and movement from the fuel sloshing around is minimized. Resistance readings at diferent float positions all checked out.
Before I did this I talked with a mechanic who said it was ok to run wires in the tank as long as everything is soldered well.

So far so good.

Additional notes: I decided to raise the bed and go in to the tank from the top.
Tip #1: you can get bedliner junk out of the bolt head by taking a razor knife and cutting a circle around the outside of the bolt head. Then pry the bedliner off and the rest comes clean out of the T-50 bolt recess.

Tip #2: Before you get ready to pull the bed make sure the bolts all break loose at least one turn. It took 2 minutes to loosen 7 of them and 4 hours of cussing and grief to get the 8th one out. If I would have known about the rusted mess of that bolt I would have dropped the tank. Used much penetrant and broke 2 T-50 sockets until I gave up and drilled the head and chiseled it off.

Tip #3: Keep a shop vac handy when taking the fuel pump ring off the top of the tank....way too much garbage that will drop into your tank if you dont keep things clean. My tank was spotless inside, which was a relief.

Tip#4: If you have an 05 and have the slow fill problem at the gas station remove the filter box back by the tank and flush all the dirt out with water. Dry it well. Have not had the pump kick off at all since doing this.

Thanks to all the advice on this problem.

 

Dan,

Thanks for getting back to us.

This more and more fill in my "kit" for understanding wiring / electrical issues.

Another problem with bad connectors / wiring.

It is sounding depressingly familiar.

 

bayou:

You are generally right - especially with gasoline.

With diesel, there is a bit more leeway.

However, that is not to say it cannot happen.

TWA lost a 747 that was suspected of being caused by bad wiring.


My theory is --- if you are going to do it, make sure you are up to OEM specs for the same job.

 

You mentioned a pickup sock on the pump in the fuel tank. My2000 7.3 F250 is acting like that sock is plugged up and not letting the fuel flow properly. Is it like a filter sock?
Del

 

My 06 had the same code and CEL on, and would drop to empty sporadically. I replaced the Fuel Level Sending unit (from Partstrain.com) part # MIPS193 Motorcraft part, costs $283.30. Dropped the tank, replaced just this part, and now it has worked fine for 4 months. I know you have tried other fixes, but just thought I would share this. My local dealership and even an independent mechanic quoted me over $500 just for the part. This part was identical to the OEM part removed, so the fix was fairly simple other than having to drop the tank.

 

This guy's truck seems to be a v-10 gasser, I still would not have any confidence in a wire repair submerged in fuel I don't care what the circumstance. I'll be watching the news for a truck exploding in traffic on the expressway.

 

As the mechanic who has worked inside many tanks told me, just make sure your connections are secured by solder.
I feel better about the condition now, than when the stock connectors were obviosly making sporadic continuity. If the stock connectors were faulty that could have caused the spark you guys mention. I now have no chance of a connector arcing because I soldered them together, plus added another wire just as a backup.
Also, note that the OEM setup has the wire soldered to a pin on the board in the sender. This wire has a small amount of copper exposed and also is open to the fuel in the tank. If that connection were to break loose you would think a spark could cross the gap. I'm thinking that is not likely since Ford does not have anything in there to better secure the soldered connection.

Zillions of tanks with OEM wiring out there and there surely have been more than one wire break loose. I don't plan on being involved in any explosions

 

Don't worry about explosion. It takes fuel and air for it. Our tanks are sealed, so there is no air in them.
I had a situation with different brand, that had pump inside the tank. The pump draws 4 amps in normal operations and it overheated and than burned out the riveted connection inside the tank. I have picture of it somewhere.
Bottom line -even with whole connector and wires badly burned there was no explosion on gasoline tank. I hear about more incidents like that -all with no explosion.
Strange at first, but true.

 

With a fuel bladder you might not have much air in a fuel tank, but our tanks are rigid and when the fuel goes out it is replaced with AIR! There is filters on both gas and diesel tanks to limit the amount of fumes that escape to the atmosphere, but there is air in the tank when it less than totally full. Thinking you can't have an explosion of fire because there is no air is simply wrong. Don't beleive it!! Geez, what happens when you take the cap off? If you don't fill it all the way, what's in the tank? Old mechanics will weld a fuel tank only if it's filled with water (with a little air space where the weld is), so they don't blow themselves up.

Sorry to get on a high horse, but I don't want to see anyone hurt. Take care, Mike

 

I have personally seen gas tanks welded full of gasoline by routing the exhaust of another vehicle into the tank to displace the oxygen. I worked on many sending units in gasoline tanks with spade connectors and soldering as needed. Diesel fuel is not generally ignited by spark and I would never be afraid to solder, spice, or connect anything in a diesel tank at 12 vdc. Can anyone give reference to an automobile blowing up due to a connection in the fuel tank?????

 

gauge moves up when key is turned on to E line then falls back low fuel light on. bought motorcraft PS238 for 142"WB. ($288) Tried unit out of tank still the same. Ran ground to sending unit from frame - gauge went to full. Whatt current should be at sending unit? Checked both wires to ground with key off - getting 10.5 volts ???? Do I need to reset computer as I saw in this thread?? and how??