[Bruckner]

Here's something I've wondered about ever since I got my 968. When fueling up, I never insert the pump nozzle all the way inside the filler neck, otherwise the flow will be interrupted after a few seconds, I always attributed this to the shape of gaz pump nozzles having changed over time and never seem to quite seat nicely in the 968 filler neck as it does on modern cars. But a friend having pointed out to me that there is a slight fuel smell in the car when driving with the windows open, now I think maybe there is more to it than I thought. I'm suspecting a blockage in the venting system. Do charcoal canisters or lines leading to it ever get blocked? Or is my thinking completely off?

 

Thanks!

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[Waylander]

The simple answer is yes they do, I have seen pictures of a 968 tank sucked almost flat due to blocked breathers


The charcoal canister has foam, and gauze separating the charcoal from the pipes, over time the foam and filter gauze break down and the charcoal drains through and fills the pipe from the rear to the canister, this pipe is not part of the normal fuel lines

It runs under the drivers side floor and is plastic

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[Bruckner]

Thanks for that. How does one go about testing for blockage?

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[Waylander]

I would suggest jacking it up drivers side, popping out the arch liner, you can then see the canister, disconnect it and check the pipe back to the tank, you should be able to blow through it, and give the canister a shake, if bits fall out, you need a new one

 

 

 

If you ant and need to replace the line its not expensive but its a real challenge to get done

Coupe 944 201 737 01 $37

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[Bruckner]

Thanks! I'll be testing in the coming days.

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[Bruckner]

I would suggest jacking it up drivers side, popping out the arch liner, you can then see the canister, disconnect it and check the pipe back to the tank, you should be able to blow through it, and give the canister a shake, if bits fall out, you need a new one

 

 

 

If you ant and need to replace the line its not expensive but its a real challenge to get done

Coupe 944 201 737 01 $37

That vent line doesn't actually connect to the tank, looks to me like it vents to atmosphere at the rear of the car?

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[Waylander]

Thats correct,

 

But it does breath in as well as out

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[Bruckner]

I pulled the rear portion of the inner fender to access the lower hose, it flows nicely without restriction, no problem there. Looking upward, the top mounted hoses seem fine, but I didn't enquire further.


I guess now the next steps will be to test the vacuum and solenoid valves on the hose going from canister to intake.


Regarding the hose that runs from the tank to the canister, I see a shut-off valve on the parts diagram, is this valve accessible without dropping the tank? Is it a one-way valve designed to prevent air to circulate from the canister to tank, or keep fuel from from the tank entering the hose?


Finally, when filling up, is the air venting to atmosphere or routed to the canister?


Thanks!

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[Bruckner]

I notice that one of the possible fault codes (blink test) is "43 Tank ventilation relay", anybody knows where that relay actually is?

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[unknown4u]

That shut off valve is near the booster from the brakes.
In the enginebay on the driverside at the top of the innerfender

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[Bruckner]

Thanks. So it is the actual solenoid valve.

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[Waylander]

Yes and its also vacuum controlled

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