1.9d Air in Fuel line and high idle

[Knocker1980]

I have a 2004 1.9d  Multispace that has decided to throw a bit of a wobbler just as I'm wanting to sell it.

It'll start and idle Ok but within a minute or two of setting off it'll start feeling very down on power before recovering and then doing it again and eventually cutting out.  It does tend to restart straight away but I have had to pump the primer a few times to get it going again too.  There is a clear fuel line fitted between the fuel filter housing and the pump and when this problem arises you can see a lot of air bubbles in the fuel line but I can't see where the air is getting in.

It's also worth noting that the idle is all over the place with the air in the fuel line but when the van is started from cold it idles perfectly and there are no visible bubbles in the fuel line, the problem only arises after we've set off.

I know it's an old bus but it passed it's last MOT with no advisories and isn't in bad condition so I'd prefer to sell it working.

Anyone any ideas?

[brodfather11]

Fuel filter drawing air at the top lid or the priming pump at the bottom of the filter assembly drawing air .
Common cause of air in fuel problems

[Knocker1980]

Fuel filter drawing air at the top lid or the priming pump at the bottom of the filter assembly drawing air .
Common cause of air in fuel problems

How repairable is the filter housing or is it easier to replace the entire thing and bin the old one?

[geoff]

In addition to the filter unit take a look at the diesel pipe from tank to engine bay as they can corrode and allow air ingress - happened to me a few years back.
Of course when the pipes get so bad they don't just allow air in they allow lots of diesel out and this will of course spoil your tarmac drive, you've been warned !

[brodfather11]

if you have had the fuel filter changed recently then I would try to reseal the top lid.
Its usually the diaphragm in the primer pump that goes and lets air to be sucked into the fuel line to the injector/h.p. pump as the fuel lift pump is built into the h.p. pump. A little air shouldn't cause any problems.   You could try to put a seal of silicon round the primer button  
OR the seal around the top lid starts leaking and drawing air.
 
(IIRC) I think that there is method of warming the fuel somehow that is under the filter housing. It may have something to do with the hot/cold performance.   

If you have fuel leaking out somewhere then the pipes between the filter and tank are suspect.  

Ebay has a selection of filter housings with varying prices , I'd not get a used one as it may be leaking.

[Knocker1980]

In addition to the filter unit take a look at the diesel pipe from tank to engine bay as they can corrode and allow air ingress - happened to me a few years back.
Of course when the pipes get so bad they don't just allow air in they allow lots of diesel out and this will of course spoil your tarmac drive, you've been warned !

As a bit of an update to this,

I've only just got round to looking at this over the Christmas break and I have noticed that there seems to be an awful lot of air bubbles in the fuel line leading into the filter housing, these bubbles are then being passed into the fuel pump and causing my issues.

As it appears to be drawing in air before the fuel filter housing I'm assuming this is going to be a fuel tank removal job so I can have a look at the state of the fuel line connections where they come out of the tank.

[geoff]

Save your fuel and any distress to your engine doing the ^^^^^^ won't make any difference.

[Sol]

Save your fuel and any distress to your engine doing the ^^^^^^  won't make any difference.

Yep.

[jimbo]

Doing the what?

[Sol]

Doing the what?

Geoff was referring to a post by someone, that seems to have been deleted, saying the OP should rev the nuts off the engine for a good 20 to 30 mins (from memory) - doing which is never a good idea (the revving of said engine in that manner)