1972 emissions?

[exc911ence]

I was speaking to the past owner of my car yesterday and he had asked if I'd had any trouble with a gas smell in the car. He told me that if I filled the tank right to the top with fuel, it would smell inside for weeks as apparently there's a emissions canister located under the cowl with a leaky hose. I guess I'm lucky that I've never topped it up that high!

Anyone know what emissions equipment my 72 911T would have and where the parts would be located?

[javadog]

Follow any small hoses you see that lead from the top of the fuel tank or the filler pipe. Porsche has put the vapor recovery/charcoal cannisters in several places over the years. There also usually a tank for fuel expansion. The typical locations for such things were in front of the trunk, in the trunk in front of the dash sheet metal, in the left front fender above the windshield washer fluid reservoir and in the engine compartment.

I forget exactly what a '72T has, and where.

JR

[RSTarga]

Charcoal canister next to the drivers side battery, expansion tank behind headlight same side. Make sure the canister is still there and everything is connected. There is also a little breather around the heater fan.

[David E. Clark]

Here is a diagram of the important emissions systems in your car.


Here is the key:
1. Expansion chamber
2. Vent chamber
3. Charcoal canister
4. Engine fan shroud (under air cleaner)
5. Hose from fan to charcoal canister
6. Purge line from charcoal canister to air cleaner

[exc911ence]

That's an excellent diagram, thanks!

[Joe Bob]

They tend to get staurated/full and then have "pass thru" issues after a number of years. They would then need to be replaced.

[exc911ence]

I'm leaning towards just removing all of the emissions nonsense since cars this old are exempt from testing anyway. That stuff would be better boxed up on my garage shelf I think.

I did a quick peek around the fuel tank and found the line from the tank to item #2 in the diagram had been disconnected. That seems a perfect place for raw fuel to escape when the tank is over-full or when cornering enthusiastically. If not raw fuel then vapour anyway.

[RSTarga]

That is your problem, you can't take this stuff off without changing or modifying your fuel tank. It is a very simple and effective system. I'm running the original charcoal canister on my 73. Just make sure all the hoses are ok and connected and that your fuel filler cap has the seal intact or just get a new cap.

[Zeke]

FWIW, I never filled my '77 "to the top" after learning that the 911 of that vintage didn't like it. No smell from then on.

[47silver]

Re-opening this thread
Does it matter on which side of the cannister the air lines connect too?

[E Sully]

It would appear that the side with the single nipple goes to the intake.

[eastbay]

I will add that I have refilled the charcoal canisters with fresh on 2 cars now to eliminate the gas smell. The old stuff just gets saturated.

[47silver]

Thanks for the diagram

[47silver]

Update
I had the piping to the charcoal cannister mixed up. After i put the piping as shown above the gas smell was reduced

[cmcfaul]

I put a one way valve (one man brake bleeder) into the hose leading to 2 (tank in the fender, as it was cracked). This allowed air into the tank as gas was consumed and did not allow gas to exit the tank by any other means. The one man brake bleeder fit perfectly into the hose and solved the problem.

Even with half a tank, a hard right turn would cause gas to flow into the tank in the left fender. Again, this solved it.

Chris,
73 911 E