Bulldawg44
New member
Hi All, I am looking for details, knowledge or basic been-there
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Just recently did this same set up with Pollack ) port and external fuel pumps. Problem: when I am switched to main tank and run bronco, after about 5 minutes, gas starts spewing out of the gas cap of the front auxiliary tank. Is this some type of vent tube issue or plumbed incorrectly?The manual tank selector valve is under the driver seat on the face of the riser. If there was originally an aux. tank in there, then you should either see a plate covering up where it used to be or the valve. It would be right between your legs if you are sitting in the pilots seat.
For EFI, you have to run both a supply & return line, and if you are going to incorporate the aux. tank into the system, you have to get an electronic tank selector valve. Any auto parts store should have those, they are anywhere from $25-100. They will have 4 ports on one side & 2 on the other, often you can call them a 6-port gas valve & the parts guy should be able to help you. The next thing you will have to have is an electric pump close to the tank. Elec. pumps (and EFI in particular) were designed for pushing fuel, not pulling it, so the closer to the tank, the better. You will have to run the supply lines from both tanks to the new selector valve & then a single line to the engine supply line. Same with the return lines. You want to make sure that the return line & supply line from the same tank are correctly hooked up or you will have some serious overflow/leaking problems when you run the larger tank.
You would use the same sending unit & you could use a vent line port on the aux tank for a return line. Look at the way that the EFI tank is run right now & just mimic it to the 6-port valve.
Here is a rough sketch of what your EFI should look something like & what original fuel lines look like. You are going to have to look close because the color didn't come through on my scanner, but the EFI drawing has both return lines & supply lines. The return lines don't go through the fuel pumps
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