New Fuel Pump fitted...takes a while to start first time

[TomD 0]

Hi all, fitted a new fuel pump the other day. It seems to work absolutely perfectly, only the first time I start it for after a good few hours (first thing in morning or after work) It won't start first time, just turns over. If you prime it a few times it will start fine though.

 

I spoke to a knowledgable mate who said that it might have air/air lock in the fuel lines/injector rail, which could cause it.

 

He also said that there's a bleed valve like a house radiator on one end of the fuel rail, which I think I remember seeing.

 

But how do I bleed it? I'm guessing the fuel pump needs to be running to do to get it to fill with fuel.

 

Any help welcome!

Cheers in advance,

Tom

[dr_mat 0]

Could also be a leaky fuel pressure regulator.

[Storm Monkey 0]

Just speculation, but there isnt a missing one way valve that stops the fuel draining back to tank is there?

[carpy25 0]

Could also be a leaky fuel pressure regulator.

 

this or maybe just hose connections not tight but it sounds like its not holding pressure

 

Rob

[Kevin Bacon 5]

The non return valve is a sprung ball valve inside the pump itself and can sometimes jam open or not quite have a perfect seal. You would be unlucky if a new pump has this problem, but it's not unheard of!

 

You could try bleeding the rail, but the fact the engine does actually fire and run kind of outrules that tbh. Just sounds like you're losing pressure over time, which could be the pump or a slight fuel leak in the pressure side somewhere.

 

My VR did the same when it's pump was on the way out.....used to take ages to start if left for more than an hour, but was fine if started inside an hour.

[TomD 0]

Ah Ok, so its losing pressure over time. When I get a spare few hours I'll pull it apart and have a good look at it.

 

Cheers for your help guys! :)

[Supercharged 2]

Is the pump running on ok?

[TomD 0]

Is the pump running on ok?

 

 

Yeah It feels as good as it ever did before, if not better. The car itself is great, pulls like an absolute train and goes round corners fantasticly, its just all the annoying niggly things that I spend so long trying to fix! Like the exhaust has now developed a leak somewhere, but only when the exhaust warms up, and then it starts to idle roughly! and then there's the knocking...

 

:)

 

I'll whip it apart next weekend when I've got a minute and check all the hoses and that its seated properly.