Fuel tank breathers

[liftlid]

Mine had a white plastic tube thingo on it that filled with mud, that caused the fuel not to suck through to the pump and lack of power and surging. If you open the filler cap and get a whoosh of air the tanks not breathing

[sooty_10]

Mine had a white plastic tube thingo on it that filled with mud, that caused the fuel not to suck through to the pump and lack of power and surging. If you open the filler cap and get a whoosh of air the tanks not breathing

Yeah that's what my cab-chassis had too, until it fell off and got lost.

[04OFF]

I thought all fuel expansion vapours are supposed to go through the charcoal canister as per emission control ADRs on all cars since about 1976 ?

[Clunk]

For those that don't know where to look, rear wheel arch (and yes mine needs a wash)
1407723550353.jpg


edit: Sorry, forgot to mention that this is on TD42 GQ, will have a look later to see if the TB42E is the same

[MudRunnerTD]

Perfect pic clunk.

[liftlid]

I thought all fuel expansion vapours are supposed to go through the charcoal canister as per emission control ADRs on all cars since about 1976 ?

Has a one way valve on it air can go in but not out

[04OFF]

Has a one way valve on it air can go in but not out

Yes correct so you dont have a vacuum in the fuel tank, also air may be mixed with the stored fuel vapour (from the charcoal canister) to be burned in the combustion process.

Fuel vapour should never vent to atmosphere, the whole point of having the charcoal canister is to prevent this from happening.

[mudnut]

Well this is a very interesting topic, because my Old Trol's fuel tank has always been under vacuum pressure when I take the cap off. I had a look under the plastic shield and found that the breather is just connected to the top of the filler. There are only three other hoses connected to the tank: Fuel out, fuel return and the breather hose. Sometimes, after a long drive, there is a weird noise, like a valve opening and air being sucked slowly through a pipe. I will have to search deeper to find out if this is normal for a petrol Patrol. The picture is of the back of the filler pipe where the breather joins it.

Edit: Just clarify it further, this picture is not the breather, but part of the filler system as noted in E.T's reply below.

[AB]

Bloody hell Winnie we must have the worst memories...lol

Look at the picture that clunk put up. Do you remember we saw that when doing the aux tanks and figured it was the breather.

Do you remember I had to bend mine a bit as it was rubbing against the dual neck?

Hopeless, absolutely hopeless!!!!

[the evil twin]

The confusion in this thread is because the -ve pressure breather is in different places on different models.

The pic that Mudnut has posted is not the tank breather... on a GU anyway.
That pipe is part of the filler neck assy and is there to stop hydraulic locks and blow back when you are filling the tank
It allows air to leave the tank as fuel flows down the filler and doesn't serve any other purpose.

In many of the early GU variants the breather is just beside the Fuel Tank Sender Unit.
It's a small placcy doover about the size of a small inline fuel filter.
They have their own pipe to the tank and are held in place by a small bracket.

There is a good piccy of the location on page FE 24 of the factory manual.
It isn't labelled in the pic or referred to in the Fuel System Chapter.

In other models it is up where Clunk has posted his pic.

I can't be arrsed looking up all the references for later models/variants but they have to have one somewhere as others have mentioned

PS... please don't ask me why the fuel caps have a +ve and -Ve pressure release as well... I don't know.
Perhaps it's a belt and braces thing.

PPS ... as I acknowledged to Mudnut... GQ's may be different, I'm not sure how they are plumbed.