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Tue Apr 28, 2015 11:44 am

Hello all, my first day here, and also a first time VW owner. So after 2 years of looking I found a 1971 Type 3 Fastback that fit my budget and condition I was looking for. Keyword there is budget, so that means time to get out the wrenches.... Being a first time VW owner I was very pleased to see my new toy came with a manual, so I am off to a good start. Besty is a pretty solid, running, mostly original (including the FI system) car.

My question is regarding the fuel system, more precisely the fuel tank. To start with I must tell you that my car may have 1970 tank and system in it, as it vents out the left drivers fender and I see no sign of a charcoal filter anywhere, and yes this all also looks to be factory. FYI Besty was built in September of 1970 so she is an early 1971.

I found that when my take got below about 5.5 US gallons of gas it would start to act as if it was out of gas. With more than 1/2 a tank it runs great. I pulled the tank figuring to find the brass sock in the tank clogged up, but actually it was in was not to bad. What I did find was a fair amount of trash in the after market fuel filter going to the new looking fuel pump. At the time it didn't seem so strange until I looked at the manual, but she had 2 fuel filters on her. 1 going to the fuel pump and the other on the line the is right beside the main fuel outlet. Looking in my manual it looks to be a return line. But would a return line go to the bottom of the tank? This and the fact that my fuel gauge does not have an E for empty, but rather an "R" like as in reserve, led me to start looking around and trying to figure out what was going on here.

When I look inside the tank I see a large round baffle that really looks like it would keep about 1/2 the fuel away from the out let....maybe? Is this part of a reserve system? If so how would I get fuel from outside the baffle? Both tubes are inside the baffle. Also the outlet tube sticks up past the bottom of the tank about 1/2 an inch or so. Is this part of a reserve system? If so then I would get my fuel from the other line which I said I thought may be a return line. Its connection is made to the tank. But it does not go to the Pump so how would it make enough pressure for my FI system?

Just a little more info to help avoid you having to ask questions. My filler tube is on the top right along with an overfill tube. then on the top left is my vent tube.

In looking my manual there should only be 1 filter between the tank and the pump. And the other line to the bottom of the tank should be un filtered and maybe a return line.

Thanks for taking the time to read this and I hope someone can explain this to me in a way i can understand how it works and what I need to do to get Besty running perfect for her whole tank of gas. BTW she also got her tank cleaned and coated while it was out.

Tue Apr 28, 2015 12:20 pm

The baffle has openings to let the fuel fully empty from the tank.

http://www.thesamba.com/vw/forum/viewtopic.php?t=569758

There is no need for any filter other than the original one between the tank and pump. Anything further is a restriction that may mess with your fuel pressure.

Tue Apr 28, 2015 1:37 pm

The purpose of the "bowl", is to make sure there is always a relatively constant supply of fuel to the pump when the level gets low in the tank and you do cornering, etc. Also, if you had the tank coated, make sure those access areas between the main tank and the "bowl" are open and haven't been clogged.

Tue Apr 28, 2015 2:37 pm

Great info thanks to both of you. What I could not see was the passage from the out side of the bowl to the inside. I thought it may act as a baffle for cornering at first, but not seeing the inlet left me concerned. Yes as far as I can tell everything is open as I could see light though both holes in the bottom.

I have put everything back together as I thought it should go (with only the 1 original filter) and she fired right up. Not to try and find out why I have smoke from the Voltage Regulator. I just installed a new generator, seems like I read something about some gens and regulators not playing nice together...I will start there.
Thanks again

Mon Oct 23, 2023 3:32 pm

I believe the bowl only works with the return line as it fills the bowl with the excess gas. If you welded up or plugged up the return line and there is no gas coming in it actually acts as a choke point and can cause problems. In this case it is a good idea to either remove the bowl by sticking a crewmen down there and cutting it out or die grinding a few vent holes in the north south east west directions. Lol what a nightmare.

Tue Oct 24, 2023 1:33 pm

andrewvwclassic wrote: I believe the bowl only works with the return line as it fills the bowl with the excess gas. If you welded up or plugged up the return line and there is no gas coming in it actually acts as a choke point and can cause problems. In this case it is a good idea to either remove the bowl by sticking a crewmen down there and cutting it out or die grinding a few vent holes in the north south east west directions. Lol what a nightmare.

Huh? That "bowl" isn't separate from the rest of the tank. There is a small opening between the bottom of the bowl wall and the bottom of the actual tank which allows gas to flow in (it's about 180 degrees of it's circumfirence). The bowl is just there to help fuel sloshing. However if the tank is really dirty/rusty, that small opening can get clogged limiting fuel flow. Lots of people run without the fuel return line hooked up to the tank.

Tue Oct 24, 2023 3:40 pm

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