Fuel Tank switching valve questions

[reklund]

Is it possible for the switching valve to fail so that only the return side of ONE tank is blocked?

I'm beginning to think my fuel leak problems at the injector caps may be caused by the switchover valve. I only notice the smell and see the leaks when I'm running on the front tank after a fillup. When the rear tank is used, I haven't noticed the problem.

Any chance that can happen?

Ryan

 

[duaneboggs]

Is it possible you have a piece of debris stuck in the valve?

I just went through this with mine, but I had sucked up a piece of the plastic strainer that tends to disintegrate in the tank. I ended up taking the the suction line off of the supply pump and blowing air back into the tanks in order to get the valve working again.

Maybe you could pull the return lines off the valve and then off the return fitting at the back of the engine and then blow air through the valve and see if you get anything out.

Duane

 

[RLDSL]

You bet. Any imaginable combination of failures can happen with those rotten things, and they usually do.

 

[towcat]

Is it possible for the switching valve to fail so that only the return side of ONE tank is blocked?

I'm beginning to think my fuel leak problems at the injector caps may be caused by the switchover valve. I only notice the smell and see the leaks when I'm running on the front tank after a fillup. When the rear tank is used, I haven't noticed the problem.

Any chance that can happen?

Ryan

one of the first tests I did on my '85 was top off both tanks when I started suspecting the fuel switching valve. YUP......it's bad. Now I get to drain the tanks to avoid getting a shower as I am changing the valve.

 

[MIDNIGHT RIDER]

You bet. Any imaginable combination of failures can happen with those rotten things, and they usually do.

X 2 ^^^ What he said ^^^.

one of the first tests I did on my '85 was top off both tanks when I started suspecting the fuel switching valve. YUP......it's bad. Now I get to drain the tanks to avoid getting a shower as I am changing the valve.

I figured a smart man like you would know this --- simply dis-connect the lines at the tank outlets, all four of them, and the fuel will remain in the tanks.

The only fuel that pours out will be that trapped within the lines.

Take the opportunity to install cut-off valves on all lines somewhere ahead of the valve and handy to access for later such adventures.


On a Ford tank, a return-line will siphon fuel just as quick as a draw-line.

 

[towcat]

X 2 ^^^ What he said ^^^.





I figured a smart man like you would know this --- simply dis-connect the lines at the tank outlets, all four of them, and the fuel will remain in the tanks.

The only fuel that pours out will be that trapped within the lines.

Take the opportunity to install cut-off valves on all lines somewhere ahead of the valve and handy to access for later such adventures.


On a Ford tank, a return-line will siphon fuel just as quick as a draw-line.

I'm open to suggestion on how to disconnect the rear tank lines at the tank without partially dropping the rear tank.

 

[MIDNIGHT RIDER]

I'm open to suggestion on how to disconnect the rear tank lines at the tank without partially dropping the rear tank.

You must have a pick-up bed; I tend to forget they exist on anything except old 1/2-ton gas-burners.

If so, were it mine, I would do some careful measuring and cut myself a useful trap-door over each tank.

This can be carefully done with an abrasive cut-off wheel or a nibbler and probably not cut anything important.


Or, take out the bed-bolts and raise the bed, then cut the trap-doors.