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Fuel smell elimination


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Had some great fun in the car today :-)

Still running through the snag-list..

Trying to nail down the fuel smell in the car and would welcome a few pointers please folks.

I think this diagram is the right one for my '74 (73 built)

I have identified that the fuel cap has no rubber seal! So that's one item 41 ticked off and probably the major cause.

Also the connecting hose smells- item 38

  1. I am not sure how filler (45) is fitted to the neck (40). Is there potential there?

Also noticed the breather hose going to the inner wing bulkhead had a loose jubilee clip. Have not checked the expansion tank (50) under the wing yet.

What is item 43?

Fuel sender (59) seems to be smell free.

Any tips appreciated.

R

 

911_1973_2_01_201-05.jpg

Edited by Rocketcar
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18 hours ago, mean in green said:

Definitely do, mine also stank of fuel before replacing the swan neck. 

Ok will remove at the weekend. 

Item 50 is the rubber shroud so there is no other potential leak path from the filler cap item 42 until item 38.

Be great to get this sorted, Fuel smell in the cabin is nasty!

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  • 1 month later...

Have now replaced the fuel cap seal and the rubber hose that joins the tank to the neck. The neck is not rusty. 

On to the breathing system I have found the next issue where the fuel smell is coming from! There is no hose connected to the small tube just below the fuel filler cap area so its open to atmosphere..

Please can anyone explain the routing of the fuel breathing system?

Looking at the parts diagram for cars up to 1974 mine should have this type, is that right? I am not sure how this is configured in the actual car?

I think it's been changed to a later type with the expansion tank behind the LH wing or should it have that too.

 

 

911_1977_2_01_201-25-1.jpg

Edited by Rocketcar
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Anyone? :unsure:

Is this the correct configuration for the breather?

If yes can anyone help with the actual routing?

Looks like there must be a line from the T item 55 which goes up to the filler neck 

 

911_1973_2_01_201-05.jpg.95ebc47ce7f9fbbd48d8f29ad7d3b0f4.jpg

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I have a 3.2, so probably not in the best position to give advice. However, I found that the tubes leading to the expansion tank under the front wheel arch were rotted, and so are well worth replacing. This will give off fuel vapour if they are holed or split. The 3.2 expansion tank then connects to the carbon canister in the opposite rear wheel arch. I found the tubes to the canister were also rotted. 

The diagram below explains the various components - but I'm not sure if it's applicable to your car. Do you have an expansion tank under the front wheel arch (hoses are probably rotted) and canister under the opposite rear wheel arch?

IMG_0421.JPG

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Hi Mobydick,

Thanks for that.

I need to check. I think my system may be earlier type but I have no idea at the moment.

Need to find someone with an early IB EU car for help, I might call a couple of the specialists as they might be able to answer this very easily and quickly.

R

 

 

 

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  • 2 weeks later...

Found out some more info last night -  thanks to Guy W for the help :-)

The breathing system is as per this diagram below (but not the upper section as this is for US cars)

Does anyone else have the breather tube just below the filler cap and can take photos of this how it's routed to the bulkhead fitting in the wheel well by the brake reservoir?

I am not sure if the hose is supposed to travel though the rubber gator on the fuel neck or if it originally went through the body work on the original wing

Also I need pics how the breather is routed in the luggage compartment via the Y piece item 9.

Thanks

 

 

 

 

 

911_1977_2_01_201-25.jpg.c5a2892b70a411e98e892f0af2328f11.jpg

 

 

 

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The filler on mine is like this with the breather pointing down rather than sideways. Doing a good search both types come up as 1974 and only 1 part number 91120104902 in that period. Unless sometimes people bent them sideways 

Porsche-911-Gas-Filler-Neck-Early-91120104902-221886256717-500x500-1.jpg

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I know you've had to answer your own questions, but good work for sticking with it and posting the outcome! 

 

I'm guessing in the yellow picture the vent tube should pass through the aperature in the wing?

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4 hours ago, Nige said:

I know you've had to answer your own questions, but good work for sticking with it and posting the outcome! 

 

I'm guessing in the yellow picture the vent tube should pass through the aperature in the wing?

Thanks Nige. Yes I am not one to give up..

The tube should indeed pass through the aperture in the wing. I think the swan neck is not positioned correctly on that car. It needs to be moved slightly towards the front of the vehicle so that the vent tube will be in line with the hole. 

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