One day, I noticed that after driving my truck on the front tank for a few days, the gas gauge hadn't gone down. The pump and sender are only about two years old, so I didn't think the sender had busted. I switched to the rear tank and noticed that the gas gauge has gone down some. I thought this was really strange, since I have the switch set to run off the front tank, and I can hear that the front tank pump is running (it is noisy unlike the rear pump). The switch works properly and I can hear it switch fuel pumps properly. I cant find any sign of fuel returning to the non-operating fuel tank, as in overflowing through the vent. The truck, however, always done the typical thing when you run off the back tank, the return goes to the front tank. So, all in all, the only thing I can think of that could be wrong is with the selector valve. I wondered though, if the engine could run off the rear tank using only the framerail pump (apparently it can) since the fuel pump switching circuit seems to be working properly. Also, where would that gas that is being sucked out by the front in-tank pump going? Here's the quick summary: Framerail and front tank fuel pump are running, fuel is being drawn and returned to/from the rear tank. Has anyone ever had their fuel tank selector valve fail, and if so, were the symptoms similar to those above? I'll do some further diagnosis this weekend, but right now, I just want to know if anyone has had a similar experience and if I'm looking in the right direction.

 

You could have a bad front pump or bad selector valve.
Yes it will run OK off the back with the back pump not running unless you run out of fuel or go up a steep hill.
The selector valve stay selected to the last tank that was selected until it gets fuel supplied to it from another tank.

 

Alright, that's kind of what I figured. The selector valve is the only thing I havent replaced aft of the fuel rail, other than the lines and front tank. The front tank pump is an only 2.5 year old bosch unit, so I don't think it's bad, especially since I can hear it running. Thanks for the help.

 

Also, has anyone actually found a fuel tank selector valve? All the stores carry universal ones and list them as the proper replacement part. Is the only place to get the real deal going to be the dealer. Oh well, maybe I can pull the recall card...

 

None of the auto parts stores sell the selector valve, just the dealer and they will have to order it in.

 

I actually found an earlier post when searching for the part number and there was a link to the site www.directfordparts.com. They had the damn thing listed for $66 dollars versus $125 MSRP. Just thought I'd put that out there, cause that's the best deal I could find.