Mk7 2.4 rwd won’t start

[J4se]

Hi all, firstly thanks for all of the great info on here, has been really helpful over the years!

Little bit stuck this time though and hope someone can help.
I’ve a mk7 rwd jumbo 140bhp that won’t start at all cold unless with easystart. It will start hot but only straight after it’s turned off and not every time.

I’ve changed: both batteries, fuel filter, egr, prv, svc and swapped relays around.

It originally had an egr fault, got to the point where it was stuck and wouldn’t start, changed it and solved the problem initially. It then started to only start second turn no matter how long you cranked. Now to no starting unless bumped or easy start. When I changed the prv it had failed but still made no difference.

Cranks fine, and I’ve even installed a temporary primer ball valve to stop fuel flowing back.

No codes now, and crank/cam sync showing ok. Immobiliser light goes out as it should .

Any ideas??!! Please!!!!

Thanks In advance

Jason

[loot]

Have you put the 2 left pipes at the filter head into a bottle of fresh clean fuel? If not give that a try just to discount it.

[J4se]

It seems more likely something electrical as the priming valve that I fitted stays solid?

[loot]

The fuel is sucked to the fuel pump then pressurised to the injectors. It is known for the filter head to fail allowing air to pass.
It has been known for the tank pipes to leak or be blocked, and the injector leak off o rings to fail. All of this results in fuel leaking back to the tank and turning the key takes ages and probably more that it takes to draw the fuel.

My old van when I bought it would not start at all in its own, I changed the filter head and never had a problem since.

Of course this might not be your problem but it is a free and easy check. It bypasses the tank and lines and filter.
I appreciate that your printer bulb stays solid but if once you get it going on easy start in guessing that it stays running which will be on the fuel then? That's the impression I get from your post.

[bambi mk 1]

Have you tried an ign switch

[J4se]

Had another look at it today, bypassed the fuel tank altogether and ran it from a can- still wouldn’t start without easystart.
Used a clear pipe and discovered air bubbles, so bypassed the filter head by connecting a second clear pipe to the return and putting in the can but there are still lots of air bubbles. When cranking the fuel seems to just return straight away from the pump- is this normal if air is present? A mate has a spare set of leak off pipes so going to give them a try tomorrow as the tiny o ring on number 2 doesn’t look too clever... is it possible for the air to be coming from the pump return? Driving me nuts now as it runs great as soon as it’s started!

[J4se]

Have you tried an ign switch

Thought the ignition switch was to do with the immobiliser not switching off?
Red lights go off as usual and cranks ok...?
And will start on the key again once running if straight after turned off (within 30secs)
So I think it’s a fuel problem and air getting in somewhere