Fuel hard lines - why do I have three?

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TriggerFish
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Post Thu May 12, 2016 8:56 pm

Hi all,

I'm replacing all the hard lines under the car (brakes + fuel). There's the two hard lines going to/from the fuel rail, which I've got replacements for. There's also a much larger diameter third pipe that looks to terminate in the fuel tank, that runs on its own.

In the engine bay, this pipe is just hanging free - it doesn't connect to anything. What would this have been, and do I need it? I'm guessing it's maybe the charcoal canister thing? (I don't have one of those present.)

I did check the Wiki, and it only pays mention to two pipes. :?
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BHadley
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Post Thu May 12, 2016 9:22 pm

Breather hose for fuel tank so there is no unpleasant smell
Other two are flow and return
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Brianmoooore
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Post Thu May 12, 2016 10:16 pm

TriggerFish wrote: What would this have been, and do I need it? I'm guessing it's maybe the charcoal canister thing?
That's exactly what it's for, and no, it's not needed, if you don't have one, and are not one of these OE types.
You can terminate the pipe at the rear, as it was on pre facelift E30s.
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TriggerFish
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Post Thu May 12, 2016 11:05 pm

Perfect, thanks Brian.

I've got a new fuel tank on order as there was some surface rust (and a smell of petrol once poked) around the filler inlet, so I'll blank it off before refitting the new tank. I do like my OE-ness, but I'm not going to keep something unneeded for the sake of it. :)
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Brianmoooore
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Post Fri May 13, 2016 12:05 am

Whatever you do, DON'T blank it off! The end of the pipe must be left open.
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TriggerFish
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Post Fri May 13, 2016 11:16 am

Ah, OK. So I can just leave a short length of rubber tube trailing at the tank end?

The pipe is a little bit rusty (MOT advisory), so I'd rather not have it running the length of the car if it'll damage my clean sheet! :)
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Brianmoooore
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Post Fri May 13, 2016 2:15 pm

This is the early set up: http://2009.bmwfans.info/parts/catalog/ ... nk_tubing/
It's not a fuel pipe, it's an air pipe, so it's arguable whether or not it's anything to do with the MOT tester.
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TriggerFish
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Post Fri May 13, 2016 4:03 pm

Gotcha, thanks.

http://2009.bmwfans.info/parts/catalog/ ... container/

I compared it to the one above for a comparison, so I can see what's happening now.

Maybe the MOT advisory was for the actual fuel pipes then, although they don't look rusty to me (but are being replaced anyway). Either way, if it's just air, I'll leave it unterminated at the start of the hard pipe in the tank area so there's no confusion on future MOTs.

Thanks, as ever, for the help :)
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