Cinquecento Cinq Sporting Fuel Tank Pushing Out Fuel?!? Help!

[LewisCinquecento91]

Hiya!
This is my first post, great app on the phone... Hoping someone out there can help me with a little problem with my new car .....:

I've very recently bought a 1998 Cinquecento Sporting and I love it, apart from one problem... When I fill up at the petrol station, the fuel is contained inside the tank, however when I drive away and start the engine, the petrol starts overflowing, coming out of the tank.. It is a slow rising, but quite a lot comes out! I would say a pint full... Also when I fill up an empty tank, the petrol pump keeps clicking as if it thinks the tank is full... It appears to me that the tank thinks it's full for some reason?! The pressure could be all wrong I suppose? In addition the strong smell of fuel comes every now and then when I am driving around, usually more so after high revs.


Someone has suggested that I need to replace my Carbon Canister which I have located right at the front of the engine bay.... I know the part (dayco b460 7742973) but I don't know if this is the problem!!

Any help would be great, I'm finding it so hard to get advice for these little cinqs, but I love the car so hope it will all be worth it in the end, Thanks !!!

 

[blu73]

Well for cento advice you have found the right place now

So does it only do this spewing fuel out when the tank is full or every time you start the car.? Where does it come from, front of tank area, rear of tank area, bit further forward, somewhere in engine bay???

the clicking all the time when filling up would suggest too much back pressure which would in turn point toward a blocked breather pipe.

Can't see it being anything to do with the charcoal cannister, the pipe from it back to the tank maybe could be loose but can't see that doing what you describe - if it was loose or split or just not attached at tank end it would smell of fuel all the time. At any rate don't replace the charcoal cannister, most cinqs that have been modded at all have just removed them - they are not needed.

Like your numberplate lol.

Oh and welcome to FF!!! :wave:

 

[LewisCinquecento91]

Hi mate thanks for reply!
Ok what it does is flow out of filler cap. The tank doesn't seem to be leaking at all, nor does the filler neck... But after a fill up (not even to the max, petrol doesn't reach cap level so maybe 80-90 percent) the petrol literally flows right up to the cap and slowly but surely trickles out for minutes...... Okay so that's one symptom.

Also, when driving around (particularly just after a high rev session on any amount of fuel in the tank) it smells of petrol again for. Few minutes.... And a couple of times I've checked the cap straight away and I've seen a bit of fuel there.

I definitely think it could be something to do with pressure but not sure what. I say this because of the petrol station pump clicks all the time as well. Also worth mentioning I've checked the two floor facing pipes near the filler neck behind the wheel arch and one of them is wet. It's not the overfill pipe from the filler cap area, but the other... Which I can't identify....

Phew, thanks!!




'98 Broom Cinq Sporting

 

[LewisCinquecento91]

Also when I tap that pipe, little drops of petrol drop from it ...


'98 Broom Cinq Sporting

 

[David C]

So the same issue you posted another thread for here...:
https://www.fiatforum.com/cinquecento-seicento/345714-cinq-sporting-over-flowing-fuel-tank.html

 

[LewisCinquecento91]

Yep, that one you provided the link to is on the Cinquecento/Seicento part of the Forum so thought I would post it there instead of the Newbie Section!


'98 Broom Cinq Sporting

 

[LewisCinquecento91]

Blu73, I thought the number plate was a personalised one when I first saw it!


'98 Broom Cinq Sporting

 

[fingers99]

I think breather pipe is most likely. They get kinked, misappropriated, and generally screwed about with when people charge tanks. Imila Blue certainly slow filled after a tank change (by FIAT -- presumably one of the trainees).

I'll see if I can root out a diagram later.

 

[LewisCinquecento91]

Ok cheers, if it's the breather is that a difficult and pricey job ?


'98 Broom Cinq Sporting

 

[fingers99]

It's not a job I'd pay someone to do. You have a Cinquecento, not a Lamborghini.

 

[fingers99]

 

[LewisCinquecento91]

Haha thanks! The pipes I mentioned aren't in the pic but that is still handy to have in case it isn't the breather. Thanks for your help!


'98 Broom Cinq Sporting

 

[LewisCinquecento91]

Hang on I've just had an idea.... Where should the filler cap overflow pipe lead to? Mine just leads straight to the floor, is that normal? So when I test it by squirting water into the overflow hole near the cap, if runs down the pipe and onto the floor.... And then there is another overflow pipe right next to it also facing the floor which has petrol in it which I'm unsure about.... Is there a possibility that these two pipes should in fact be joined? And that the cap overflow pipe leads to the tank like in the pic?


'98 Broom Cinq Sporting

 

[fingers99]

The smaller one by the filler cap isn't an overflow, it's the breather pipe. It has to go back to the tank or the tank will try and vent through the main filler pipe (which will make it burp).

 

[blu73]

I think its tank breather related also - you may have to drop the tank to get at the tank end of the pipe, but there should be a pipe (number 10 on the pic fingers posted) that goes from the top but forward face of the tank upto the filler cap area. I have a feeling that if you got a pipe hanging straight down from the filler area that will be it - but sounds like someone may have been messing and it could just be blocked off at the tank end as car would stink of fuel and it would just pour out all over the place if you filled the tank until the level is below that pipe. From experience that is until you get down to about half a tank.

I would say if there is petrol leaking back past the filler cap it probably needs the seal replacing - not had to do this myself but i believe there is an o-ring that can be replaced - failing that the lock barrel can be removed from a new cap and swapped with the barrel from the existing cap. But you should investigate and fix the breather first - one thing at a time as the saying goes

PS> Don't post questions in the newb section in future - the only reason you got a response to this is because FF is magical and the cinq/sei prefix you selected means its shows in the cinq/sei section where us cinq/sei people lurk.


edit: worth mentioning as well, on the breather pipe at the tank end there should be a a rubber bit that in on the tanks metal pipe that the plastic breather clamps down onto to create a proper seal - they normally stick to the tank when you pull the pipe off and so if the tank has been changed at some point its possible the rubber bit was left on old tank and the car would have been leaking fuel and some genius thought best solution was to pull pipe off and block it to stop it leaking - just a thought

 

[LewisCinquecento91]

Morning, I drive the car for about an hour this morning with no smell, but at the end of the drive I hit around 4500 rpm and the petrol smell came back temporarily!.... Anyways Thanks so much for the help guys, about as concise as I could've asked for... I will have a play and post the outcome when I know the problem! Sooner rather than later hopefully, thanks again.




'98 Broom Cinq Sporting