Hi all, I bought a 94 F250 7.3 turbo IDI and the front fuel tank never worked. I noticed when I switched it to the front tank the fuel gauge would max out, so I bought a fuel tank selector valve and installed it. That's when I noticed the line from the front tank was full of kind of a tar substance and had the smell of real old diesel. I had to run a wire through the line back to the tank to get any fuel to come out with a fuel pump. My question is, will the tar substance eventually clean out with the diesel? I also put about 3/4 qt of type F transmission fluid in the tank to aid in cleaning. It will idle, but if I hold the throttle down about 3/4 of the way, it starts running out of fuel until I switch it back. Just idling it seem to do ok, the exh seems a little hot, but I'm not sure.

Oh, there are stickers on the back bumper saying bio diesel, so someone might have used that a while back.

What are your thoughts?

 

Honestly, with all that crud in the line and tank I would replace the line and pull the tank and clean it out. If it has that much buildup of an unknown substance it cannot be good for the IP.
It probably starts running out of fuel due to a inline restriction, you said that you had to run a wire to get anything to flow so the line is probably partially blocked.

 

I decided to go ahead and pull the tank and lines and clean everything up just to be safe. The front tank is the big tank so I really need to get it working.

 

pulled the tank and it looks real bad inside so I ordered a new one.

The pickup looks bad too, but that is real expensive, so I will try to clean it up first.

 

the factory ones are but the aftermarket are not hard to install.
https://www.ford-trucks.com/forums/9...highlight=fuel

 

The pickup, the strainer and the sending unit are separate parts. The sending unit is the expensive part. The strainer is available on Amazon. You can test the sending unit with an ohmmeter.

Gauge pegging to full does NOT indicate a bad selector valve. If anything, it indicates that it switched tanks, and thus switched sending units, properly. Pegging past full means infinite resistance, aka an open circuit. If it works correctly on one tank, but pegs on the other, most likely the sending unit in that tank has either failed, or simply been disconnected. That's the first thing to check.

 

X2 what he said, don't worry about your IP cuz your filter will protect it, just after you run a few tanks through the new tank change your filter, some have a water sensor in the bottom and a drain to remove the water periodically napa gold is 10 micron about 36 bucks.