Rear gas tank issues

[salineriverman]

Finally getting my bronco close to finished - I installed a new rear tank and hoses as well as removed front aux tank and had it cleaned. Put a new valve on as well - new floats in both tanks. Was running off rear tank and it ran out of gas - didn’t get gauges to work- so I switched to front tank. It’s been running great off the front tank . I failed to say I had to install a small electric fuel pump and left the mech. pump on as well. Then I Tried to go back to rear tank but can’t get the fuel to flow and bronco goes dead. Took gas line off at valve and gas flowed free all over me ! It’s almost like an air lock?? I removed gas cap to see if vent issue. Still didn’t pump. When I switch back to front tank electric pump picks up gas and bronco runs like a charm.
Any one had a similar issue? Thanks for advice in advance-

 

[Oldtimer]

Which model electric pump, some of them will not pull fuel very far from a tank.
Where is electric pump physically located?
Did you bypass mechanical pump, or leave it in the fuel flow?

 

[salineriverman]

I had installed two mechanical fuel pumps and neither pulled enough gas thus I installed the Eldelbrock small pump not sure of model - after the valve that switches tanks- I also have two inline fuel filters - one before electric pump and one before carb- It could be a distance thing?

 

[salineriverman]

My charcoal canisters are gone - but it ran for years without them - the canister is still in panel behind the seat with lines hooked up - some gas still makes it in it.

 

[salineriverman]

Mechanical pump is still in fuel flow.

 

[DirtDonk]

the canister is still in panel behind the seat with lines hooked up - some gas still makes it in it.

This won't help with your issue, but when you say gas gets into the recovery tank behind the seat, do you mean that you can smell it, or that you can see liquid physically getting in?
And if liquid, how often, and is it a lot?

Thanks. Sorry I don't have any insight on your current flow issue yet.

paul

 

[salineriverman]

Cannot smell it but could see it - it’s not much but it was noticeable when I was putting cover back on after paint job.

 

[salineriverman]

Which model electric pump, some of them will not pull fuel very far from a tank.
Where is electric pump physically located?
Did you bypass mechanical pump, or leave it in the fuel flow?

I think you’re onto the issue - I read where pump needs to be within a foot of gas tank - Mine is probably a foot from front tank but no way to position it to rear tank due to needing to be on out feed side of tank selection valve??? Any ideas?

 

[Oldtimer]

My mechanical pump has been pulling gas from both tanks for a least 20 years with no issues. The only filter is inline near the carb.
If you installed floats on both tanks I assume tanks are clean, and filter socks on end of pickup tube are in good shape.
You may want to start by replacing every piece of rubber fuel line in system. Check valve for air leaks. There may not be fuel leaking out, but air leaking in from pump suction will cause all kinds of grief.

 

[salineriverman]

My mechanical pump has been pulling gas from both tanks for a least 20 years with no issues. The only filter is inline near the carb.
If you installed floats on both tanks I assume tanks are clean, and filter socks on end of pickup tube are in good shape.
You may want to start by replacing every piece of rubber fuel line in system. Check valve for air leaks. There may not be fuel leaking out, but air leaking in from pump suction will cause all kinds of grief.

Thanks , I’ll check it and see.

 

[cldonley]

Is your mechanical pump working? It should pull fuel from the rear tank without any help. You might also want to make sure fuel is flowing freely after the valve when its switched to the rear tank.

 

[gnpenning]

Instead of replacing parts test them first so you know if you are fixing a problem or creating a new one. Fuel volume is one of the easiest and cheapest tests you can do.

Like cldonley said, have you checked for fuel flow on the outlet side of the switch over valve?

Always double check how you rotate the valve so it is going the right way.