Injection pump bleed screw Xantia 1.9TD '94

Wishy · Unread post by **Wishy** » 14 Dec 2006, 20:07

Sorry for the stupid question but where on earth is this bit?

Just got the car and pretty sure I have air ingress problems from reading other threads on here. Please bear in mind that I've been trying to find it in the dark with a torch so a photo of where it is would be much appreciated.

My Haynes manual shows the one from the 2.1TD which bears no ressemblance to my car.

Any help would be much appreciated.

P.S. I am not the most clued up person with regard to engines so no laughing please.

Unread post by **CitroJim** » 14 Dec 2006, 22:13

Not a silly question at all.

Welcome to the forum Wishy!

They do not have a bleed valve and nor does it really need it. Bosch Pumps, unlike Lucas CAV pumps, are self-bleeding to an extent. Turn on the ignition, pump the primer bulb and fuel will flow right through the pump even when not rotating.

This does make them very sensitive to air leaks though, especially in the leakoff pipes, the filter housing and the priming bulb. There are some excellent Posts on this forum dealing with the subject extensively.

Wishy · Unread post by **Wishy** » 14 Dec 2006, 22:32

That would explain why I couldn't see it then

Ta

The other options I'm looking at this weekend (when it's light) are the ones you mentioned.

Cheers

jeremy · Unread post by **jeremy** » 14 Dec 2006, 23:47

Many older systems had basically 2 separate fuel systems - the tank to the pump circuit incorporated an engine driven lift pump and generally it was necessary to bleed this circuit if the fuel ran out. This was often acomplished by loosening one or two screws on the injection pump while the lift pump was operated.

Having accomplished this it was then necessary to bleed the high pressure system by loosening one or more injector tubes. Usually the engine would start after one or two had been done.

The pumps used on the XUD incorporate lift pumps and are simply primed by operating the inbuilt priming pump. The high pressure bit seems to look after itself.

Unread post by **Peter.N.** » 15 Dec 2006, 14:45

Just to add ... The older systems didn't have a return pipe to the tank, the leak off fuel was fed back to the filter. The modern systems are 'full flow' in other words the fuel is constantly being pumped through the pump and back to the tank. If you only get a few air bubbles they will pass through the pump with out incident, on the old system they would have stopped the engine, you need a lot of air to do that now.

jeremy · Unread post by **jeremy** » 15 Dec 2006, 16:15

BMC 2.2 and Land Rover diesels had tank return pipes to the tank - wished the BMC didn't - as I wouldn't have had to fit the thing when I put one in a petrol Land Rover.

These would have been Late 50's - mid 60's components.

Unread post by **Peter.N.** » 15 Dec 2006, 21:11

I'm thinking more of Perkins 4/108s. Used quite a number of those in conversions.