Citroen C5 Mk1 (Jan 2004), 3.0 V6 starting issue

[citroenesque]

Hi all,
It's been a while!
I've got myself a sweet ex-Citroen UK C5 V6 and she's great. But recently developed a fault I would like an opinion as to what could be causing it.

If left over night (or even a couple of hours) the car will turn over fine but won't catch. Turning the key short of starting the car, leaving it about 8 seconds and repeating a three of four times cures it and it usually fires up no problem after that. Once running it goes perfectly. And if I stop, and return within a few minutes, it'll start fine too.

Sounds like a fuelling issue to me. Though I might be wrong.... Any thoughts (and suggested process in tracing and curing the fault)?

FYI it happens no matter what the fuel (currently 98RON) the fuel level (I usually keep it above 1/3 tank), outside temperature....

Cheers!
Phil Chidlow

[myglaren]

Small leak in the fuel pipe from the tank allowing air in and thus the fuel to drain back into the tank but not large enough to let fuel leak out. Takes the pump a while to drag the fuel through.

[citroenesque]

Ahha. Sound likely. I'll need to get it looked at asap. Don't want it getting worse.

[myglaren]

The usual trick recommended on here is to put a piece of transparent fuel pipe near the HP pump where it is easily seen and check for bubbles, indicating air ingress.

[citroenesque]

Thanks

[Kees]

There is no hp pomp on a v6 3.0/24!
The pressure is around 3.5 bar, it's possible, that the pressure regulator is bad, and release the pressure.

[wheeler]

Yes this will be a petrol V6?
Can you hear the fuel pump priming when the ignition is switched on?
Once it eventually starts does it run normally?
Really want to have a look at live data whilst its not starting & see if you can see engine RPM.

[citroenesque]

I have a replacement fuel pressure regulator.
The pump does prime, yes. And it runs perfectly normally once it fires up.