fuel sensor in forward tank failing?

[Allen McCready]

When the forward gas tank first read empty, yet still had plenty of gas, it turned out that the cylindrical 2"x1" float was filled with gas due to a hole that the suspension bracket had worn in it.

Eventually, I ended up replacing the whole fuel pump assembly, which includes the float, with a new assembly. That worked for a week or two then the gauge started rapidly wandering anywhere from full to empty. After a few days of this it stayed on empty, but still pumped gas for many days. So, it's not the pump. The gauge works fine when I switch the fuel system to the rear gas tank, so it's not the gauge.

When, I removed the fuel assembly from the tank, plugged in the electrical connector, turned the ignition to "accessories", switched the fuel system to the forward tank, and manually moved the float to the full position, the gauge read a steady full. As I manually moved the float, the gauge moved accurately with it. Then, I unsuccessfully tried moving the wires, tapping on the connector, etc. to get the sensor to fail.

As a result, the float and sensor have worked outside the tank, but not in it.

ANYBODY HAVE ANY IDEAS?

My only action plan is:
1. Put the assembly back into the tank, as is and try it again.
2. If it fails again, try a replacement under the lifetime guarantee from Advance Auto Parts.

This was the fourth time I removed the assembly from the fool tank.

[mrfixit64857]

sometimes those infernal floats, even the new ones, have pinholes and perforations in them. as you say, it is time to cash in on their guarantee and get a good one.... this may sound silly to ask, but is it installed facing the same way as the last one? so it's not hanging up on baffles or vents or reserves? seems to me they made this less possible in recent years, but ya never know

[Allen McCready]

Originally Posted by mrfixit64857

sometimes those infernal floats, even the new ones, have pinholes and perforations in them. as you say, it is time to cash in on their guarantee and get a good one.... this may sound silly to ask, but is it installed facing the same way as the last one? so it's not hanging up on baffles or vents or reserves? seems to me they made this less possible in recent years, but ya never know

Thanks. I will double check the float when I take the assembly out of the tank to see if it has any gas in it. I had a spare new float that I got from the dealer and used it the last time I re-installed the new assembly, but the guage still read empty. I checked the picture for the assembly before I put it back in the tank the last time. There was nothing in the way, e.g., baffle, that I could see with the assembly out of the tank. However, there is an extreme possibility that the float is somehow catching on the very shallow strengthening ribs in the tank. I will check that again, as well as the alignment of the float, before re-installing the next assembly. I left one of the good floats floating in my lawnmower gas can overnight, but it didn't sink. I realize that is not the same as being weighted down by the sensor lever.

Incidentally, after I wrote the above message, I put the assembly back in the tank and used a coat hanger to reach in and move the float up and down with the electrical plug connected. The gauge worked fine. However, when I put five gallons of gas in the 17 gallon tank, the gauge still read completely empty.

Could my gas tank be haunted? After all Ford van is nav drof spelled backwards, which makes as much sense as what has been happening.

[mrfixit64857]

Using those letters you can also say it is:
No Nova Nor Road Rod roan of a van....
when you put the 5 gallons in, was it back in the vegical? (misspell intentional) It may be a broken wire in your harness that breaks connection in the installed position; grasping at straws here...

[Allen McCready]

FYI:

I returned the forward tank fuel pump assembly to Advance Auto Parts, got a replacement under the warranty, and installed it. The fuel gauge now works for that tank.

When I installed the replacement, I shoved the rubber plugs for each of the wires as far as possible into the electrical connector to the fuel pump assembly. The rubber plug for the wire for the gauge may have been out too far, and may have caused the wire to disconnect intermittently, if that is possible. Otherwise, the problem was the sensor on the assembly.