Occasional smell of raw fuel

[Juan]

Hi all , I took my VZ to Sydney yesterday . On the way down on two occasions I smelt raw fuel inside the car.
I stopped the car straight away. Looked under the hood no smell of fuel.
Looked in the boot no smell of fuel . Looked under the car no smell or any sign of dripping fuel.
I did fill up with fuel just before starting out and found the fuel cap was not quite tight. Tightened as much as I could.
On the way home just after negotiating a roundabout it happened again.
At home I looked at every thing that I could see with a torch in and under the car and can't smell or see anything leaking. Ran the engine while inspecting it.
Its got me beat what it could be.
The only thing I did find was some rat droppings on the left side chassie member that is right beside the engine.

However as far as I can tell I can't see any damaged wires or hoses of any kind.
How do I remove the black plastic side covers from the engine top so I can see better?

[danja]

Alloytec or V8?

[Juan]

Alloytec or V8?

Sorry I should have said . Alloytech.

[boofis]

Hi Juan,

There's been a few discussions on this in the past. More often than not, it seems to lead to the fuel cap not sealing correctly... I get the same thing in my VZ occasionaly (not often). I've been meaning to replace the fuel cap under warranty but haven't got around to it yet.

Have a quick read of this thread, and see if you can find some others (there is somewhere, but I can't seem to find them at the moment :P)

petrol smell with ac on????

[baracuda]

i had the same(and sometimes it comes back) its the fuel cap and /or the filler neck on the petrol tank. i had the tank replaced as the filler neck is all moulded into 1 unit,luckley was all warranty at the time. and had like 3 new caps during the time too. i find after i fuelled up and put the cap back on i need to squeeze the cap a lil and just make it click like 2-3 times and its firm. i dont hold the cap by the handle as its then garanteed to come lose.
if i fuel the car up in the morning i check the cap again when its been sitting all day at work (more paranoid then anything i think lol)

[Juan]

Thanks boofis & barracuda . I went and checked the filler neck and did find some small ridges in the plastic on the sealing surface. After some polishing with 600 wet and dry it is nice and smooth now.
The cap seal seems ok and not damaged.
I tightened it a bit extra than I have been doing and took it for a 1 hour test drive . Hammered it all around these steep hills and tight curves and rammed the brakes on quite a bit. No fuel smell has returned this time out.

I did find a rubber hose at the back of the engine that I think is the fuel line.
It connects to a circular boss extending out from the fuel injection area.
It is loose on both ends as it goes over a metal pipe. It will not pull off but swivels around the pipe with ease . Does this sound normal?

If fuel fumes are escaping at the filler cap then they could be finding their way into the body work via the hinge assembly cut out of the filler cap cover.
The cover does not allow any ventilation to the outside as far as I can work out but may allow ventilation to the inner body works.
Not sure I like this at all. Maybe I am wrong on this.

[andyman]

I did find a rubber hose at the back of the engine that I think is the fuel line.
It connects to a circular boss extending out from the fuel injection area.
It is loose on both ends as it goes over a metal pipe. It will not pull off but swivels around the pipe with ease . Does this sound normal?

If fuel fumes are escaping at the filler cap then they could be finding their way into the body work via the hinge assembly cut out of the filler cap cover.
The cover does not allow any ventilation to the outside as far as I can work out but may allow ventilation to the inner body works.
Not sure I like this at all. Maybe I am wrong on this.

yes fuel supply line is normal,

filler neck shouldn't breathe at all due to the fact the charcoal canister is meant to look after this

[Juan]

Thanks "andyman".
Where would I find the open end of the charcoal canister breather pipe ?

[andyman]

Thanks "andyman".
Where would I find the open end of the charcoal canister breather pipe ?

funnily enough, there is a breather cable tied to the top of the filler neck, but the main vent for fuel vapor get sucked into the engines intake as part of the evaporative emissions control system,,


how full do you fill the car? i recommend stopping at the first or second click, if you overfill the tank you run the risk of fuel running into and filling the chaocoal canister up with fuel, this may be a source of smell

[Juan]

I usually stop as soon as the fuel pump clicks off and I insert the nozzel all the way.
However I filled up in a station I don't usually use so it may have still over filled it .
On the way home from Sydney the tank was only 2/3 full and it happened again just after I changed the aircon vent from fresh air to recyle.
However at that stage I was not tightening my cap as much as I do now.
As stated above a susequent test drive has not shown up any more fuel smell with an extra tight cap.
I think any fumes that are excaping from where ever are entering through the rear vents. Would it be practical to seal up the rear vent near the right hand side ?
It is due for a service soon anyway so I will get them to check all the pipes and hoses .

[baracuda]

with the loose cap i noticed the fuel fumes were going through to the boot then from there into the car.

[Torquative]

dont forget the fuel system is pressurised so if the caps not sealing 100% as it loses fuel it creates a vacuum which works against the cap as well, which will alow the scent to escape.