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Fuel tank question????


V8Freak

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So I was going too order a fuel tank today and apparently there were different options? He asked if I had 2,3 or no vent lines? [you said a naughty!] lol, so I look at opgi websites and there's two different options:

W/o EEC

3 vent w/EEC

Can anyone clarify this for me?

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I am pretty sure that the 3 vent is for non vented gas cap. The 3 vent were used in 72. The tanks with a vented cap sometimes leave a trail of gas during launch. I run the 3 vent with 2 capped off and the other vents the tank. I am going to change to a 1/2 inch vent with a roll over valve when I sump the tank.

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2 vents went to a canister behind the backseat which then had a line to charcoal canister left of the radiator & 1 vent was to the fuel pump. That's how my 71 was setup (built May 1971)

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70 had a vented tank where the vapors escaped out the vented gas cap. 71-72 had the EEC system with the tank behind the seat and a charcoal canister. If you have eliminated the canister and all the lines you can go with a 70 tank w/o EEC but make sure you use a 70 vented cap.

 

I removed all the extra stuff on mine and blocked off the extra vents and went with the vented gas cap with no issue.

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  • 1 month later...

I need some help. I have a non vented tank with a vented cap. When I open cap it is under high pressure..

This is a new tank from opgi. I had to replace it cause the original tank had a hole at the top, and when I filled up, gas fumes filled the car.

 

Side by side the tanks look the same. No vent tubes.

 

Previously, the fuel pump had to be changed. The fuel pump had only one line, but there were two lines coming from the tank. Based on other post the second line is a return line. I got a new pump with both lines. now everything is connected back up.

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Welcome to the site! 2beers

 

From what you posted, your vented cap isn't venting anything. A vented cap that's working will let the inner tank be open to the atmosphere. No pressure build up.

 

Also, there was actually 2 different systems used for 1970. The non-vented tank with the vented cap for cars delivered everywhere except CA. The California cars had a carbon canister mounted on the frame, not on the radiator support. In '71 it was moved to the support and all Montes got them. I'm not versed in how the '70 Canadian cars were equipped, but my guess is they had no canister.

 

Dan

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My 71 has all kinds of tubes and canisters and stuff. If your interested here are a few pics and a page from my 71 shop manual.

BTW, a shop manual is a great item to have!

Bruce

71 fuel tank pics

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Thx for the response. The funny thing is, is that I have 2 new vented caps, and the issue is happening on both. I guess I need to have them tested to see if they are working properly. I believe they should open up at 10psi..

 

If they test good, then I'm back to square one.

 

Joe

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Forgot to add, it's a 70 with a 72 front end.. I bought it this way a few years back. Trying to get it running again. It sat for over 10 years.

 

Non vented tank. The sending unit has two lines a supply and return.

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