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D2 - Engine Bay Everything under the bonnet

View Poll Results: Is the tube is supposed to be in the Engine bay somewhere?
Yes 1 50.00%
No 1 50.00%
Voters: 2. You may not vote on this poll

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  #1  
Old 27th December 2019, 07:29 AM
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Default Should this mystery tube be under the bonnet? **UPDATE - MYSTERY SOLVED**



While I was cleaning up the plastic covers when investigating an oil leak yesterday, I came upon a mystery tube. It looks like the straw on an aerosol can.

Should it be there? I pulled on it gently and it moves upwards several centimeters but I did not want to pull too hard just in case. It looks a little random to be where it is. Has it come off something engine related or is it an OOOP?

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Thanks,

Paul

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Last edited by C4R 100N; 29th December 2019 at 02:02 AM. Reason: added picture of plastic covers
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  #2  
Old 27th December 2019, 09:15 AM
MikkiJayne MikkiJayne is offline
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I'm going with 'no' because that's not an OEM part I recall ever seeing before. What's it connected to? It looks like its just stuck in beween the wiring harness and the end of the inlet manifold. There's nothing interesting in that exact location iirc.
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Old 28th December 2019, 02:36 PM
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Quote:
Originally Posted by MikkiJayne View Post
... What's it connected to? It looks like its just stuck in beween the wiring harness and the end of the inlet manifold. There's nothing interesting in that exact location iirc.
Well...! I had a quick squiz in the dark tonight because this tube was nagging at my curiosity. Encouraged by your belief that it was not supposed to be there, I gave an even harder and more persistent tug at the tube tonight but it would not budge.

I could not see where the tube went; into the nether regions behind the back of the engine? So I positioned myself on the other (left hand) side of the engine, and gave another tug and shone a light from my phone towards the approximate place where the tube should be visible if it went to that side of the engine.

I discovered that the tube is attached to a rubber breather? hose which is attached to the side of the engine. I've got no idea and I can't see the part in ETKA. I drew a red arrow pointing towards the other end of the tube where it connects to the rubber elbow which, in turn, seems to be plugged into the side of the engine (don't know what to call that bit where it plugs in).

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There is a wider view attached to this post.
Any ideas?
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  #4  
Old 28th December 2019, 04:16 PM
MikkiJayne MikkiJayne is offline
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oh wait, is that the vacuum supply to the fuel pressure regulator? The regulator is the cylinder in your second pic of the first post. It should have a vacuum line connected to the opposite end to the fuel pipe.
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Old 28th December 2019, 04:43 PM
HPsauce HPsauce is offline
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I'm sure I replaced my FPR a while ago and don't remember anything like that.
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2003 D2 FL S8. Irish Green Pearl/Beige. Solar sunroof, auto-dim mirrors, electric rear seat functions, ski hatch retrofit; extended leather. Aftermarket DVB-T, reversing camera and full XCarlink (Bluetooth etc.).
2016 Volvo V40 T5 Cross Country (4WD) with ALL the toys including adaptive cruise etc. etc. Osmium Grey with Blonde/Charcoal leather interior. Polestar performance "optimisation". (A much rarer model than a D2 S8 by the way!) Oh, and a brand new engine at just under 30,000 miles on the factory one!
Finally: gone, but not forgotten.....
1998 D2 PF S8. AgateGrey/Platinum. Every option (I think) except electric rear seats, tiptronic steering wheel, ski hatch, towbar & dimming door mirrors.
e.g. Cruise control, NavPlus/TV, Bose, GSM, Xenons, Solar roof, Parking sensors, Alcantara/leather everywhere of course. (internal dimming mirror added later)
1998 (very early) Ford Focus 1.8 Zetec; ABS/TCS, Heated screen/mirrors, Aircon, Auto-dim mirror, Leather, Trip computer, Cruise control, OEM Ford SatNav with CD changer.
And before that a lot of Rover 800s, a few oddities, a lovely Triumph Dolomite 1850HL with Overdrive and way back in my schooldays an Austin Seven aka Mini 850!
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Old 28th December 2019, 05:02 PM
MikkiJayne MikkiJayne is offline
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This is a standard Bosch regulator as used in the D2:



The o-rings go in the housing in the fuel rail and the manifold vacuum connects to the port on the top.
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Old 28th December 2019, 05:05 PM
HPsauce HPsauce is offline
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Looks extremely familiar and I'm pretty sure mine had an anonymous black vacuum hose.
(Though having just done a search, it was actually over 5 years ago so my memory may be faulty...)
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2003 D2 FL S8. Irish Green Pearl/Beige. Solar sunroof, auto-dim mirrors, electric rear seat functions, ski hatch retrofit; extended leather. Aftermarket DVB-T, reversing camera and full XCarlink (Bluetooth etc.).
2016 Volvo V40 T5 Cross Country (4WD) with ALL the toys including adaptive cruise etc. etc. Osmium Grey with Blonde/Charcoal leather interior. Polestar performance "optimisation". (A much rarer model than a D2 S8 by the way!) Oh, and a brand new engine at just under 30,000 miles on the factory one!
Finally: gone, but not forgotten.....
1998 D2 PF S8. AgateGrey/Platinum. Every option (I think) except electric rear seats, tiptronic steering wheel, ski hatch, towbar & dimming door mirrors.
e.g. Cruise control, NavPlus/TV, Bose, GSM, Xenons, Solar roof, Parking sensors, Alcantara/leather everywhere of course. (internal dimming mirror added later)
1998 (very early) Ford Focus 1.8 Zetec; ABS/TCS, Heated screen/mirrors, Aircon, Auto-dim mirror, Leather, Trip computer, Cruise control, OEM Ford SatNav with CD changer.
And before that a lot of Rover 800s, a few oddities, a lovely Triumph Dolomite 1850HL with Overdrive and way back in my schooldays an Austin Seven aka Mini 850!

Last edited by HPsauce; 28th December 2019 at 05:14 PM.
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  #8  
Old 28th December 2019, 11:26 PM
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Quote:
Originally Posted by MikkiJayne View Post
oh wait, is that the vacuum supply to the fuel pressure regulator? The regulator is the cylinder in your second pic of the first post. It should have a vacuum line connected to the opposite end to the fuel pipe.
Of Course! Thank you!

That will explain the strong fuel smell that I have been getting - mostly on cold starts. Is it normal for fuel to dribble out of there? I remember replacing the FPR on my A6 sedan and it was leaking out of that top tube pretty badly.

I think that I can go hook that up as I believe that I have some of that tubing laying around, what with owning 3 C4’s.

**EDIT - UPDATE - MYSTERY SOLVED**

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It turns out that the rubber elbow was still installed on the FPR so I just needed to insert the wayward tube into the elbow and all is as it should be. I did not notice (obviously) that nothing was connected to the other end of the elbow on the FPR.

On my C4's this connection was by way of rubber braided hose and was only a very short trip to the manifold. I have never seen the the hard plastic tube on my other cars. Perhaps it lasts longer or something?
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Last edited by C4R 100N; 29th December 2019 at 02:05 AM.
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  #9  
Old 29th December 2019, 10:35 AM
MikkiJayne MikkiJayne is offline
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Quote:
Originally Posted by C4R 100N View Post
Is it normal for fuel to dribble out of there? I remember replacing the FPR on my A6 sedan and it was leaking out of that top tube pretty badly.
No, it shouldn't leak fuel from there. If it does, the internal diaphragm is split or perished and it should be replaced. Manifold vacuum acts on the back of the diaphragm in conjunction with the spring to ensure that there is a constant 4 bar across the injectors relative to the inlet manifold, rather than atmosphere (1 bar already).

I get easily mixed up about how it goes wrong without it connected - I think it runs lean, but I'd have to look it up to be sure. The ecu can compensate to an extent with the O2 sensors.
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Old 29th December 2019, 11:01 AM
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Quote:
Originally Posted by MikkiJayne View Post
No, it shouldn't leak fuel from there. If it does, the internal diaphragm is split or perished and it should be replaced.
Oh well. It won't hurt me to take the covers off again. I will be expert at that soon! I did not check whether the fuel was leaking out of the top port, but I can definitely say that there is no fuel smell after having reconnected the vacuum to the FPR. That probably means that it is leaking from there and that I will have to get a new FPR. I will check that tomorrow.

Quote:
Manifold vacuum acts on the back of the diaphragm in conjunction with the spring to ensure that there is a constant 4 bar across the injectors relative to the inlet manifold, rather than atmosphere (1 bar already).

I get easily mixed up about how it goes wrong without it connected - I think it runs lean, but I'd have to look it up to be sure. The ecu can compensate to an extent with the O2 sensors.
Thanks for the extra information. Always learning something new! I took the car for a good drive this afternoon (about 100km). Hopefully the ECU will have readjusted to the reconnected port. I can't say that I noticed any difference to how it performed on the drive.

I've put about 2,500km on the clock since I've owned the vehicle - mostly joy riding - and it certainly has been a joy! Some of the most enjoyable km's that I have ever driven in a vehicle! I am loving this S8!!
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