Xantia - odd starting

[Jaf]

Just wondering if this rings any bell? Fred starts much, much easier when the fuel tank is full. With even a half full tank I have to use the fuel primer bulb, though not if the engine has been started that day. Also hates starting on a slope.

It's not really a problem, just weird and plays on my mind.

[MattBLancs]

Fuel running back to the tank sounds like the symptom.

I was quite surprised to find on my C5 (X7) that the fuel pickup point cap doesn't seem to be the highest point of the tank, when more than about half full it's above the level of the opening with said cap removed.

So, hypothetically, say the pipe connectors on top of this connection weren't sealing properly, perhaps that is a route for air to enter, allowing the fuel to drain back (but perhaps only when the fuel tank level is below the level of these connectors?

Perhaps my hypothesis is well off the mark, but definitely sounds like fuel drawing back slowly.

Fuel filter housing is also relatively frequently accessed, so perhaps another (easy to access on an XUD!) Thing to investigate?

[CitroJim]

Hi Jaf

Matt, you're not off the mark at all

This almost invariably points to a very small air leak in the fuel system somewhere... Just a tiny one right now...

First suspects will be the leakoff pipes and the little 'dead-end' plug on the last injector and then the fuel filter body, specifically a little air leak around the white 'crosshead' with the star washer on the side... This is the end of the fuel thermostat and a known cause

Lots of threads on here about it

[moizeau]

As above ^^. Does it start better if parked on a slope facing the other way?

[aerodynamica]

Hi Jaf

Matt, you're not off the mark at all

This almost invariably points to a very small air leak in the fuel system somewhere... Just a tiny one right now...

First suspects will be the leakoff pipes and the little 'dead-end' plug on the last injector and then the fuel filter body, specifically a little air leak around the white 'crosshead' with the star washer on the side... This is the end of the fuel thermostat and a known cause

Lots of threads on here about it

Hi Jim, this is what was the cause was in my 1.9td Xantia. Firstly it was the leak off pipes and then I had the usual leak at the white plug at the bottom of the black diesel filter housing.

[Jaf]

Ahhh! I knew that one of you would know. Bit of a design flaw if you ask me, like the coolant header tank.

I did glue the fuel filter, oh years ago. I keep meaning to redo it.

Lottie cat, supervisor.

[MattBLancs]

Bit of a design flaw if you ask me, like the coolant header tank.

Is that like the 306 one - fine so long as you can just reverse gravity briefly whilst bleeding the thing? (header not the highest point, hence needs water to flow up hill)

[MattBLancs]

P s. Didn't think of leak off pipes, but yes that's a very good shout

[CitroJim]

Loving your cat Jaf