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D2 - Fuel and Exhausts Everything to do with getting fuel into the engine, and fumes back out again

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  #11  
Old 12th November 2020, 07:28 PM
HPsauce HPsauce is offline
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Quote:
Originally Posted by MikkiJayne View Post
It could be disconnected from either side tbh. I might try that before I get out the parts cannon
That was in line with my thinking, disconnecting a single pipe at one end or the other would hopefully be a lot easier than removing a unit, but just as useful for diagnosis.

Follows my basic diagnosis rule: only change one thing at a time..... (unless you're very very clever)
__________________
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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  #12  
Old 12th November 2020, 08:40 PM
MikkiJayne MikkiJayne is offline
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These are some pics I took of the pipework. They actually doesn't help at all with understanding how the vent system works, or indeed what the problem might be, but maybe someone else will be inspired...

The vent lines from the top of the tank. The small one is the front right, medium (blue stripe) is the front left and front upper combined, and the large (blue and yellow stripes) is the upper rear.



This is what Elsawin calls the 'expansion unit', shown roughly in the orientation it is in the car. The fitting to the top right of the pic is the top surface and is horizontal. This contains the gravity valve, and feeds to the valve for the vent release in the filler neck. The upper of the hoses to the left is the one which goes to the charcoal can.



In this view you can see that the upper rear tank vent goes straight to the top of the filler neck.



Top three go to the tank, to blue/yellow, black, and blue in top-to-bottom order.



Hose for the charcoal can



This is the pipework from the charcoal can. Top right is the line going forward to the N80 valve. Lower middle is from the filler neck assembly.



Closer view. Right is the pipe to the filler neck. Left is the vent to air from the can. This is a closed system with no openings other than these three pipes.



Given that the main tank vent goes straight to the top of the filler neck I don't see how that can be the cause unless the hose has collapsed. Any filling solution (petrol pump or gallon can) is putting fuel in below where this pipe attaches

If the charcoal can is blocked then that could block the lower tank from venting via the expansion unit, but the top of the expension unit can vent in to the filler neck through the vent valve so its still a mystery.

I think I need to burn some fuel off and then pull the driver's side arch liner out and check all the hoses are intact. If they are then I'll disconnect the charcoal can in there and see what happens.

Alternative suggestions welcome though...
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  #13  
Old 12th November 2020, 10:11 PM
HPsauce HPsauce is offline
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That's not logical, captain...…
Either you've misunderstood what you have in front of you. Or it was installed incorrectly, or (something else)….
It doesn't make sense for the top of the tank to vent directly to the filler tube, it surely must go via the charcoal canister?
Surely the whole point of all this complexity is vapour recovery?

Although on second thoughts it must need to vent quickly somehow during filling? I know there are some types of fuel fillers that include vapour capture.
__________________
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; 13th November 2020 at 10:17 AM.
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  #14  
Old 13th November 2020, 01:08 PM
HPsauce HPsauce is offline
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Quote:
Originally Posted by HPsauce View Post
That's not logical, captain...…
Or more likely it is and it's me that's confused.

So I've just been reading up on the general principles around the canister, something I knew nothing about before....
They collect vapour given off by the fuel that might otherwise be vented to the atmosphere at any time, typically through temperature changes while parked.
So they are in line to a pressure release valve and vent de-vapoured air, in this case presumably via the pipe noted as 5 on the earlier diagram. I'd guess the pressure valve is incorporated into the cylinder unit somehow.

When the engine is running and reaches certain conditions another valve opens and air is sucked in through the canister (presumably also via pipe 5) to purge the vapour from the carbon into the engine air intake.

I struggle to see how any of that could cause an airlock blocking 2 gallons of fuel entering the tank.

Though I'm still not clear about pipe 9 and the vent into the filler tube. Most vapour will be coming up pipe 9 so that needs to vent when under pressure via the canister. I guess when the filler cap is open it just passes by the canister and into the filler tube; when not fuelling that will be sealed to the outside so it can somehow route back to the canister.
Quote:
This contains the gravity valve
what does this do?

I'm wondering if you dare connect an air line (if physically possible) to the vent into the filler tube and blow back down it?
__________________
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; 13th November 2020 at 01:44 PM.
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  #15  
Old 13th November 2020, 07:00 PM
MikkiJayne MikkiJayne is offline
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Quote:
Originally Posted by HPsauce View Post
I struggle to see how any of that could cause an airlock blocking 2 gallons of fuel entering the tank.
Likewise, now I have also looked in to how its working

Quote:
Originally Posted by HPsauce View Post
Though I'm still not clear about pipe 9 and the vent into the filler tube. Most vapour will be coming up pipe 9 so that needs to vent when under pressure via the canister. I guess when the filler cap is open it just passes by the canister and into the filler tube; when not fuelling that will be sealed to the outside so it can somehow route back to the canister.
what does this do?

I'm wondering if you dare connect an air line (if physically possible) to the vent into the filler tube and blow back down it?
This is pipe 9:



It comes out in the filler neck here:



The other two vents go through the expansion unit, through the gravity valve (which seals the vent system if the car turns over) and then in to the filler neck through vent valve thing.

Normally if you press this valve with the fuel nozzle it'll hiss a little and allow you to get another gallon of fuel in. It doesn't appear to have any effect on Big Red.

At the moment the lower connections on these lines should be full of fuel so I will wait until I've burned some off and then investigate. If there is no obvious damage to them then I probably will blow the air line down them and see what happens. If one of them is blocked it has to be from some sort of debris in the tank, since there's no way anything else can get in there.

Failing that, I will probably swap the expansion unit and see what happens.

Its a pain troubleshooting the last 2 gallons from a full tank when I do 4 miles a day
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  #16  
Old 13th November 2020, 08:31 PM
HPsauce HPsauce is offline
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Ah, great explanation. I looked into my filler pipe but couldn't understand how the 2 different connections were made. And the gravity valve is just a crash safety item.

If pipe 9 is blocked wouldn't it also slow down normal refuelling throughout as that's presumably a (or the) main way of air leaving the tank as fuel flows in?
Did you notice that at all?

And is that little nipple thing from the expansion tank pipe a valve of some sort?
__________________
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; 13th November 2020 at 08:34 PM.
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  #17  
Old 13th November 2020, 10:35 PM
MikkiJayne MikkiJayne is offline
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In normal filling the displaced air will just come up the filler neck past the stream of fuel. There are no issues with that. I'm fairly sure the problem happens when the fuel level goes past the level of the filler neck entry to the tank and because the vents aren't working, the displaced air then has nowhere to go. Parking on a slope allows the air to escape up the filler neck again hence why there is room for two more gallons.

Re the nipple thing, that operates a valve which is connected to both the top of the expansion unit and the charcoal can, and it's just occurred to me that it is probably operated by the fuel cap, given its location. I use it a lot in my A6 as when I press it with the filler nozzle I can get an extra gallon of fuel in the tank.

I wonder if it connects the expansion unit to the filler neck when the cap is off, but to the charcoal can when the cap is on? I can test that with compressed air tomorrow.

Last edited by MikkiJayne; 13th November 2020 at 10:38 PM.
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  #18  
Old 13th November 2020, 11:20 PM
HPsauce HPsauce is offline
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Now this might sound really stupid, but part of the D2 S8 specification, IIRC, is an extra 10 litres or so (2 gallons roughly) fuel capacity.
I wonder if that's not a physically bigger tank but actually a cleverer venting system, combined with a different fuel sender/gauge?
And you've got a problem on Big Red that means it's reverted to "standard" fill but with an S8 measuring system?

Or maybe it is a physically bigger tank (at the top) with extra venting so it can be used? Does ETKA or similar help identify the fuel tanks and venting systems S8 vs A8?
This my S8:
0M6 Fuel tank
1E1 Activated carbon canister
1Z5 Increase in initial standard fuel filling

If that little valve is operated by the fuel cap (as well as a filler nozzle?) it surely (if like your A6) can only open up the vent. It appears to have a small shield to prevent it being pushed in too far or damaged.
Not sure that would do anything at all with the fuel cap on as it will just connect the top end of two pipes already connected at the bottom? Maybe just allow the fuel in the vent pipe to flow down smoothly as the level in the tank drops with use, a clever detail avoiding gurgling? Might have a look at the geometry tomorrow.
I assume, maybe not correctly, that as fuel level drops air enters the system from the top through a valve in the filler cap.
__________________
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; 13th November 2020 at 11:37 PM.
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  #19  
Old 14th November 2020, 09:36 AM
MikkiJayne MikkiJayne is offline
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Funnily enough, I wondered about the tank size when I got the car as there was a hint in Elsawin that the 2.8 / FWD models got the 80 litre and the V8 / quattro models got the 90, but I spoke to Maria about it and she confirmed UK cars all got the 90 litre. The 80 litre is a different, smaller tank. I would guess its shorter at the front, since the fuel level senders are the same.
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  #20  
Old 14th November 2020, 11:36 AM
HPsauce HPsauce is offline
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Quote:
Originally Posted by HPsauce View Post
If that little valve is operated by the fuel cap (as well as a filler nozzle?) it surely (if like your A6) can only open up the vent. It appears to have a small shield to prevent it being pushed in too far or damaged.
Just had a look and it is a small lever that is pushed down into the tube when the filler cap is fully screwed in. So presumably is designed to open to allow air in to the very top of the tank as fuel is consumed.
Or if it's the other way round, why? Is there an easy way to test with the units MJ has off the car?

It has a shield around it that is probably designed to actually prevent a filler nozzle touching/moving/damaging it.
__________________
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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