C5 2.0 DOHC (2006) - Diesel failing to feed in to engine

[quincam]

Hi!

First time Citroen (and diesel) owner here. My 2006 C5 2.0 HDi 16 (with the DOHC) was recently failing to start. Called out roadside, and they traced it to a short on the lift pump. Ordered a new one, fitted it, and drove to the shops, a mile or two away.

On the way home, lost power, engine cut out. I could hear the lift pump making pump noises, but I could only get engine to turn over and start briefly, and any use of accelerator would cause it to stop again, and eventually, it wouldn't start. Next day, after reading in Haynes manual about how I should have used the priming bulb, I walked back to the car.

Squeezed the bulb and diesel squirted out of a hole in the side.

Eventually obtained a near-match part, and fitted it. Primed away for the next minute or so. On trying to start the car- the battery being a bit flat by this point I should add - the bulb swelled up to twice the normal size, maybe even more. Alarming.

Tried a few tests. Firstly, when detached from the fuel filter (I have this one: http://www.sogefifilterdivision.com/cat ... href=FC582 ), I can "prime" diesel all over the floor. I examined the filter- it looks quite clean. But anyway, tried to bypass it by connecting the bulb-side hose to the filter output hose. No difference. Still swells up like I do when left alone with ice cream.

I think this explains the hole in the original bulb, it simply over pressurised, and burst.

What's next, would you fine folks recommend? Is there anything upstream of the filter other than the high pressure pump? That's a pricey part considering I didn't even pay a grand for my comfy grey tank.

Apologies in advance if I'm not providing the right kinds of information. Let me know, I will investigate and report back. I have a very basic ODB-II reader available, but no Lexia or the like. I'm going to charge the battery so that if any solenoids or similar are failing to operate due to weak voltage, hopefully that'll solve things.

Also, on no diagrams- including the manufacturer's ones, can I see what the electrical connector is for on top of the fuel filter housing. Is it sensing for fuel/air, to check if the filter is primed?

Huge thanks for any advice!
QC

[Hell Razor5543]

Hello, and to the Forum.

I am NOT certain if this will help, but there is, I believe, a pressure regulator on the high pressure pump. It is not unknown for this regulator to, over time, get blocked. This would stop fuel getting into the engine.

Something else I would check (but make VERY certain not to let anything fall into it) is the fuel filter housing. If you find any tiny brass fragments in there clean out the filter housing very carefully. This brass bits will have come from the lift pump, as it started to fail (they are a clear indicator of such).

I would also suggest looking on the following link for any Forum members near to you who have a Lexia, and are willing to help out. It could give you more information;

https://www.frenchcarforum.co.uk/forum/ ... 19&t=56452

[Paul-R]

I thought that hand primer bulbs were only fitted to engines that didn't have a lift pump and relied upon the high pressure pump to provide all the suck. Or was that only early cars?

[wheeler]

I thought that hand primer bulbs were only fitted to engines that didn't have a lift pump and relied upon the high pressure pump to provide all the suck. Or was that only early cars?

Correct, if it has a hand primer bulb it shouldn't have a in tank lift pump, beware though it will be wired up to have one so it will work if you fit a pump, normally it blows the hand primer after a few days/weeks.
Seen it loads on 2.0 HDI Xsaras with siemens systems when the non existent LP pump is misdiagnosed as being faulty.