1977 bronco fuel selector problems

[Wilzy014]

hello everyone,

I'm having an issue with the fuel selector valve. I just installed a new 23 gallon tank as I've been using the aux tank for quite some time now. Issue is when I change the fuel selector valve to the main tank from the aux, no gas seems to be getting to the engine as it will cut off.

The gas lines running to the valve are new so do I simply need a new 3 port valve? Thank you for any insight

 

[chuckyb]

Welcome. Are you sure that you have the hoses routing correctly in and out of the valve? Are you seeing any fuel leaks at all underneath? Conventional fuel system with pump and not EFI? I rebuilt my valve and replaced the o-rings. but it’s been a while. I would think that if the handle on the valve is turning, the more likely problem would be a leaky valve rather than no fuel at all.

 

[Bronco-Brian]

I found my 77 bronco selector behaves differently than the one in my 70. The 70 selector swings 180deg to switch tanks. The 77 uses 90 deg swing to switch main to aux. I found this out having the same issue as you. A quick check is to remove the carb supply hose, and blow air back towards the tank in all 3 positions and see how it is working or not working. You can hear the air going inside the tank to ID it. One other quick note - be sure your fuel cap is vented. It must vent to allow fuel to be pulled by the mechanical fuel pump.

 

[SHX669]

As they said ^^ check how your valve is " plumbed " . Usually the inboard outlet goes to the main tank the outboard goes to the Aux and the center outlet to your fuel pump.
The " lever " usually swings 180* to change from tank to tank with the " pointy" end facing outboard for the Aux tank.
Notice I didn't say anything definitive - I've learned not to where EBs are concerned - LOL
Something else to look at/verify -- we replaced the valve in my Sons Bronco with a new one from a Vendor ( dont remember why) but it wont function properly by using the pointy end / lign up approach . His Clicks for the different positions so it has to be turned left or right until we hear a click otherwise the valve isn't fully open.

 

[Wilzy014]

thank you for the help. I know where the selector lever needs to be for the aux tank. So when i turn the lever 180 degrees to use the main tank, is it possible that I am turning it off and therefore only need to turn it 90 degrees so the lever is pointing up?

 

[Wilzy014]

conventional fuel system. no leaks

 

[Wilzy014]

 

[SHX669]

thank you for the help. I know where the selector lever needs to be for the aux tank. So when i turn the lever 180 degrees to use the main tank, is it possible that I am turning it off and therefore only need to turn it 90 degrees so the lever is pointing up?

That's possible - if someone has " plumbed " it differently . Usually turning it 90* turns it off.
The best way to tell is crawl under your Bronco and look at how the fuel lines connect