Electric Fuel Tank Selector Valve- Troubleshoot

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Bfix "What's a Bronco?"
Bfix "What's a Bronco?"
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Electric Fuel Tank Selector Valve- Troubleshoot

Post by B-man » Mon May 04, 2015 2:32 pm

Is there a way to troubleshoot this part?

I have a 73' Bronco. The previous owner removed the mechanical fuel switch and installed the Tank Selector Valve.

Now, I believe the valve has gone bad. It won't switch to the Aux tank. For the past 10-12 years, the rig ran fine, both tanks worked. This is a new problem.

Can this valve be cleaned out? With compressed air? Or, is it in my best interest just to purchase another?

Thanks in advance for any info or help.
1973 Bronco. 302, mild cam, C4 Auto, Posi front and rear, HEI Dizzy, Edelbrock intake and 4 barrel Carb, 33X10.5 wheels/tires.

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Post by DirtDonk » Wed May 27, 2015 9:27 pm

did you get this sorted B-man? Sorry the forum has been so slow. I couldn't even log on for awhile and I have to admit I even stopped trying.
Is this the single terminal, 3-port solenoid style valve? Or the 6-port Pollack type with a fancy Weatherpack type connector?

Easiest way to test a solenoid type is to first test for voltage (should be full battery voltage, or close to it) at the wire. Should be power in only one position of the switch, but no way to know which one until you test both with the key on.
If you don't find any power, you need to check the switch itself. They often go bad.
Then check the wiring to make sure it's kosher. I know you said it worked fine for years, so chances are the wiring is correct, but it could still be "bad" from age.

If you've got voltage and you don't hear any clicking of the solenoid, make sure the unit is well grounded to the frame, and that the frame is well grounded to the battery. If it is, and you get no clicky, then the valve it likely bad.

If you get a click, then it's time to dig into the hoses. Disconnect them and make sure there is gas at both Main and Aux sources. Blow some light compressed air (about 10 lbs should be fine) through the ports with the dash switch in each position to see if air does go through.
If it does, then on to plan-B

Hoses can leak air, causing erratic behavior.
Solenoids can wear out.
Switches can die (and often do!)
Crap can get into the hoses and ports, but is usually easy to clean out.
The filters can clog. Make sure that the PO didn't install too many inline filters and check the "sock" filters in the tank for deterioration. While not an accurate test, some light compressed air reversed into the tank will at least let you hear if it's flowing or not.
Wires can deteriorate too, so verify full voltage. Any loss means either a break or pinch or corroded connection.

Good luck. Usually simple, but can take time to track down.

And if you figured it out, post up here even nobody answered until now.

'71 Bronco - 302 4v
3.5" WH/Skyjacker Lift
33 x 11.50 x15 Thornbirds on 15x7 Enkei's
Kayline soft top
Hanson bumpers
Dual batteries, Large 1G alt.


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