pressure from fuel cap?

ScoobyDoo69 · 4 Apr 2006 at 12:58

for some strange reason recently, when I go to fill up the car, i remove the fuel cap, and it makes a dumpvalve like noise PCCCHT type of thing, where pressure is being released... It's not normal I would imagine, but what could cause it? :confused:

Ta

ScoobyDoo69

happytechie · 4 Apr 2006 at 12:59

it means that as the engine draws the fuel out of the tank the air can't get in to replace it fast enough. I guess there should be a breather pipe somewhere that might be blocked, don't worry about it

HT

ScoobyDoo69 · 4 Apr 2006 at 13:03

that's quite worrying...

Sputnik II · 4 Apr 2006 at 13:04

A friend of mine had same type of problem with his Honda Civic some years ago. It would actually build up pressure in the tank, He took it back to the dealer a few times but, I dont ever recall him saying it was cured.
As already said it must be a blocked tank vent I would have thought.

L0rdMike · 4 Apr 2006 at 13:06

Is it not air being sucked in rather than out though?

Firestar_3x · 4 Apr 2006 at 13:06

Nothing wrong at all, fuel injected cars need a pressurised fuel tank, your just releasing the pressure in the system, my MX does the same thing

ScoobyDoo69 · 4 Apr 2006 at 13:07

L0rdMike said:
Is it not air being sucked in rather than out though?

not a clue... lol

I've read somewhere before that there is something called a carbon catcher.. or was it canister? that fills up, so just empty it, but I honestly have no idea about that!

Firestar_3x · 4 Apr 2006 at 13:09

Nope thats just for the car to come in line with new enviromental standards, if your getting enough fuel in that you have serious problems it, should be tiny amounts.

Capt Doufos · 4 Apr 2006 at 13:09

My MX5 does it occasionally as well.

Firestar_3x · 4 Apr 2006 at 13:11

In a car with electronic fuel injection, the injectors squirt fuel into each cylinder. Fuel in this type of system is kept highly pressurized with the help of a pressure regulator. Due to the high-pressure system, the fuel lines must be made of metal. Sometimes the fuel filter in a high-pressure fuel injected system is placed in a low-pressure section, and may be connected to rubber hoses with hose clamps, much like in a carbureted system. However, the fuel filter in a high-pressure fuel injected system is usually equipped with a threaded fitting on each end that screws into the fuel lines on either side.

Like i said nothing wrong

Thats why when changing the fuel filter you should take the fuse out for the fuel pump crank the engine, this will stop petrol spraying all over the place when you take the fuel line off

TONY · 4 Apr 2006 at 13:12

My Audi TT does it everytime I fill up and has never given me any problems.

ScoobyDoo69 · 4 Apr 2006 at 13:13

nice one Firestar_3x

Ukadder · 4 Apr 2006 at 13:14

Calibra use to do it and the BMW does it as well, never noticed anything bad comeing from it.

Phantom · 4 Apr 2006 at 13:15

mine does it too, is it going to blow up?

Firestar_3x · 4 Apr 2006 at 13:18

Phantom said:
mine does it too, is it going to blow up?

Yes just make sure your in a field full of children at the time.

Enfield · 4 Apr 2006 at 13:41

I don't think it's anything to worry about mate. Mine does it too.

Phantom · 4 Apr 2006 at 13:50

Enfield said:
I don't think it's anything to worry about mate. Mine does it too.

you need to find a field full of children asap too then

Mickey_D · 4 Apr 2006 at 13:50

It's actually caused by oxygenated/methanol mixed fuel being shaken. When shaken these type of fuels "foam" and give off vapors. It happens all the time over here as ALL fuels are either oxygenated or methanol mixed or both.

It's nothing to worry about and is a normal condition for these fuels.

Fishman · 4 Apr 2006 at 15:06

I seem to have more pressure released the closer to empty my tank is.

thedazman67 · 4 Apr 2006 at 15:15

Happens in my car normal according the the owners manual.

thedazman