Fuel pump hissssssss

[NCred02]

Let me start by saying I do a search before heading here to absorb the massive knowledge here. And thank you for all the help!!!

When we turn the key to ignition on, but not start, the pump sounds like a tire thats letting air out. When I remove the gas cap there is a lot of pressure built up.

The car also takes three tries to crank it over and you have to have your foot on the gas pedal.

The three lines , two on the pump, and the other one that runs to? What is that?

Have a good weekend!!!

 

 

[GTSBoy]

There is a breather system, via the charcoal canister in the engine bay, to a vacuum source on the inlet manifold. This is an emmission control to prevent fuel vapours escaping to atmosphere. They are caught in thee charcoal canister and burnt off when the engine is running. This system should be plumbed up properly and working because it doesn't hurt anything and is good for the environment.

If it is not plumbed up and working properly, then it could cause all sorts of odd behaviours. But I would be very surprised if it could interfere with starting. A pressurised tank would not make it hard to start. Should make it easier to prime the fuel rail, if anything.

If it is pressurised, then that could just be from warm fuel, but, if some numpty has plumbed it up wrong, it could be boost, which would be bad, and bad. You could pop the tank in the most extreme outcome imaginable.

[Duncan]

do you have any way to get a fuel pressure gauge on the system? my guess is the pump is simply dying. if you don't have something any decent mechanic should be able to check static fuel pressure for you.

re releasing pressure when you open the cap, this is normal and fine. The cap should be vented to allow both air in as the tank empties and air out if the tank heats up and the fuel expands, which you might notice most during spring as the weather gets warmer (not that I know if it is spring where you are, there is no location on your profile :))

[NCred02]

@GTSBoy  @Duncan

 

Found the issue. The hose on the fuel pump was oversized and had a small split.

Still getting a lot of pressure when removing the cap and when fueling the pump shuts as full multiple times.

I'm thinking vent line on tank either blocked or pinched