ScottR

Hi All

Happy New Year!

Or not so happy from my car! I've got fuel dripping out of my flushing air pipe (i.e. the open ended pipe that comes from the charcoal canister).

Any ideas what's causing this?

Not sure if it's relevant but I always get a hiss of air when I unscrew the fuel tank cap.

Any help appreciated as not sure whether it's safe to leave the car! Or start it??

Thanks
Scott

ScottR

Hi

Giving this a little bump as I'd really appreciate some advice.

Not sure whether the charcoal canister is more commonly referred to as a the carbon canister.

Cheers
Scott

Indycam

I would try and give you some advice
but I don't know what to say .
Is the hiss of air , air going in or going out ?
How much gas is dripping out ?

jneteler

Are you sure its petrol that is coming out of the pipe? Did you touch or smell it to verify?

I'm thinking it might be water condensation from the air. Otherwise, the implication is that the cannister is flooded with petrol.

JNeteler

springer3

Don't light a match! Is it possible the fuel was over-filled recently?

tbennett017

Do you get a Check Engine light? Often that will go off if you have an issue there. I don't know a ton about this, but the Car Talk Guys are always saying that if you are getting a hiss out of the fuel tank, there must be a check valve that isn't doing its job somewhere. Do you smell fuel in the trunk area?

ScottR

Thanks all, in order:

The his of air comes out when I unscrew the fuel cap - as if pressure relief.

The petrol is coming out of the rubber hose near the rear left wheel - exits just in front of the shark fin behind the bottom skirt (door seal body bit!).

I had to take the door sill off to find it but there was a patch on the garage floor so knew it was coming from there.

I think it must leak quite a lot intially because the (dried stain) patch is quite big but the actual dripping when I found it was like a slow dripping tap.

Definitely petrol. I found it due to fact that I parked the car in the garage, came in and after a few minutes the kitchen stank of petrol where the fumes were sneaking their way in from the garage.

I was even worried about flicking on the garage light the fumes were so strong!

No, I always stop filling on the first click from the pump (unless the pump was faulty).

No warning lights.

The car has always been a little fumey up front (and inside if left for a while) but I read a lot that this is a common problem and just hadn't got around to looking at the pipes.

I read something about a check valve too on my research journey. And something that this could cause the canister to flood but I really can't find anything extensive.

I'm happy to change the canister...if I could find where it is! It's only abouot £35 so not a bad punt. Anyone know how to get to it though?

The car is my daily drive for work so I need to get it sorted ASAP so any continuing help/ideas is much appreciated.

Indycam

Ok , now I might have half a clue .
The tank needs to be vented . Old tanks were vented via the cap .
This was changed to the trap system . The vent to the outside was via a trap .
The trap grabbed and held the fuel that would have just gone out into the air .
When the engine starts the fuel trap is connected to the intake system and the trapped fuel is burnt .
Your trap valve system is not working as it should , imho .
The gas that is collected in the tank is not getting sent to the intake system .

ScottR

Yep, think you're right.

Some research suggests changing the carbon canister first as these can get old and not hold on to the fuel vapor so well but it seems odd to me that this would suddenly make a lot of fuel spill out.

Seems more likely that a valve is failing as you suggest. I'm just not sure what parts to systematically look at and/or replace.

Harry Apps

Have you got any further with this yet? I was thinking thro' your problem this pm. Because the charcoal can should only absorb vapour, it shouldn't contain fuel as such. As far as I can see, it's not directly connected (piping) to a fuel supply line. Therefore, in theory (mine), you should be able to run without the canister for a short while. Not sure where the tank vent pipe is exactly but would assume its near the top so shouldn't leak/spill.

Have you got Adrian's book - there is a schematic diagram on Page 144. If not, PM me and I will see what I can do.

Regards

H

ScottR

Hi Harry

I haven't managed to any further physical inspections as I've been away all week for work.

But I spoke to Peter at GT One - he's one of the the PGCB 964 regsiter tech advisors. He's advised I carry out the following initial checks:

- Check the flushing air pipe for blockages/correct fitment
- Check the carbon cannister is in good shape
- check the valve solenoid that controls the flow of vapours to and thro the carbon cannister is working

I'll give these a go first, hopefully this weekend unless the snow falls again and kids want to go sledging!

I'll update my findings.

Scott

PS Yes, I've got Adrian's book but it does seem to go into any detail about this part of the fuel system. I know the diagram you mean.

ScottR

I probably should't speak to soon but I think I've solved it .

The actual pipe (flushing air pipe) was blocked good and proper. Took the pipe off the canister and couldn't even blow through it.

Some flushing water and some prodding send a stone on it's way and a lot of dirt.

From what I've read about the canister and the fuel system I guess by having a blocked flushing pipe the vacuum will draw fuel from the tank rather than pull air from the outside.

The canister has thre ports - one for the flushing air pipe, one for a hose that comes from the tank and one for a hose that goes to the engine (labelled as motor - i.e. off to get burnt).

When it needs it (the vacuum and solenoid control that), the motor will draw air from the canister grappbing the vapour that has collected on the charcoal/carbon. The flushing air pipe allows air in so as not to cause a vacuum. The vapour gets in there from the expansion tank on top of the fuel tank. And there's the loop. If the flushing air pipe is blocked, the motor will try to draw the vapour, get no release from the vacuum and start pulling fuel through the expansion tank.

Well, that's my read on it anyway! From the bits of info I've managed to collect! I could be wrong with the explanation but my pipe is not clear and it doesn't seem to be leaking fuel after running the engine.

(note, the fuel only leaked when the engine was switched off because the motor is not longer drawing from the canister, but the canister is now full of fuel and it slowly drips out through the flushing air pipe by way of gravity).

Fingers crossed I've fixed the right thing!

Thanks to those that have helped on the replies and a big thanks to Peter at GT One.

Scott

Indycam

Sounds fixed to me , cool beans .

ScottR

I reckon so - drove it to work today and there's no sign of any leaking fuel

fasterlaster

i had the same problem this past week. It appears that all the rain lately caused the gunk In my drain tube to block causing the same symptoms. Cleaning the drain tube was the fix. Thanks