Petrol fumes

[Gold 'N' Brown]

Last couple of days I've detected a slight smell of petrol after shutting off the engine on the V70. My boy's car seat is on the rear OS so I park up, switch off and in those 30 seconds it takes me to get out and open his door and get his seatbelt off, I can smell the fumes. I haven't smelled it at all with the engine running (and my wife has crazy super acute sense of smell so she would have noticed any fumes inside the car weeks before I did!). I tested it yesterday, with the engine running, I had the car seat out and the seat base folder up, pulled back the foam bit under the seat and I was sniffing away in that area and down by the wheel/sill and couldn't detect anything until the engine was shut off, then had fumes for about 30 seconds.

Questions:
1) Is there any logical reason why fumes would only be forced out (or even an actual petrol leak) in the 30 seconds after shutting off the engine?
2) What should I be checking?

I've done the obvious and had a quick look under the car at the filter and surrounding area and no sign of a leak (filter is only a few years old too). Tank was filled up a week ago, and not overfilled (just to the first click on the pump, and it took the expected amount). Fuel consumption on the computer doesn't seem any worse so pretty sure there's not an actual significant leak.

[Doingitsideways]

May be barking up the wrong tree, but I seem to remember something about the carbon canister only actually doing something when you switch off?
Maybe the return line from there?

[LeeT5]

Have your codes read as you may have a faulty Vacuum pump in the carbon canister circuit.

Have you checked under the bonnet to make sure you've no fuel leaks around the injectors and fuel rail?

[Gold 'N' Brown]

Not checked under the bonnet yet, but the smell definitely is only coming from around the rear OS/rear OS back seat (I really need to do another test to see if I can only smell it inside the car or if it's coming from outside only).

I had a read about the carbon canisters and failure of the J hose last night. The symptoms people describe are just about bang on the same as mine.I need to do handbrake cables and faff about with my back box before the MOT so I'll have a snoop around the canister while I'm under there.

[htomi]

I'd also pull up rear seats and take off the both pump and sender unit covers to see if there is any petrol on top of the units. Takes literally 2 mins. No need to take out the pump or the sender, just the metal cover which is held by 4 bolts.

[Gold 'N' Brown]

OK, pretty certain it's not coming from inside the car. Had a full car last night - 2 kids, wife and MIL - and none of us could smell anything inside whilst driving. I stopped and we all sat there breathing in deeply and still couldn't smell anything. Got out and could smell it around the back of the car, then it quickly disperses. I think based on what I've read that a problem with the carbon canister system seems most likely, so I'll get under and check it soon.

[Dangerous Dave]

My V70 (P1) had a similar issue, could smell petrol.

Turned out to be the fuel filter (which wasn't very old) had corroded around its bracket and was letting a tiny amount of fuel out which wasn't noticeable until it was removed.

[LeeT5]

My V70 (P1) had a similar issue, could smell petrol.

Turned out to be the fuel filter (which wasn't very old) had corroded around its bracket and was letting a tiny amount of fuel out which wasn't noticeable until it was removed.

Leave the ignition 'ON' (engine off) and reinspect the fuel filter again. Undo the bracket and check the whole filter. :B_thumb:

[Harvey]

There's a alloy vent pipe next to the main filler that can corrode have a good look in the wheel well to see if there's any staining.

[Gold 'N' Brown]

The smell seems to have disappeared as the tank has run down (I'm now down to the last 1/4 and haven't smelled it all recently). Although I did undo the cap and poke the flap in, around about the time I first posted this thread, just in case of a vapour lock.

I had a snoop underneath yesterday. My god that carbon canister is well hidden! I don't fancy having to do any maintenance on that! But all the hoses to it appear OK. I checked the J pipe that apparently is common to split and that is fine. No sign of any leaks or corrosion up under the filler and down to the tank. I did forget to inspect the filter again so I'll do that next.

[LeeT5]

The smell seems to have disappeared as the tank has run down (I'm now down to the last 1/4 and haven't smelled it all recently). Although I did undo the cap and poke the flap in, around about the time I first posted this thread, just in case of a vapour lock.

I had a snoop underneath yesterday. My god that carbon canister is well hidden! I don't fancy having to do any maintenance on that! But all the hoses to it appear OK. I checked the J pipe that apparently is common to split and that is fine. No sign of any leaks or corrosion up under the filler and down to the tank. I did forget to inspect the filter again so I'll do that next.

Mate, the first thing I'd replace is the filler cap! I replaced mine as the seal was very hard and cracking.
They're not expensive and come with the rubber seal. Then refill the tank to the first click and see how it goes.

[Gold 'N' Brown]

That's a really good point Lee, can't believe I overlooked that!