XM Fettling - Bubble Trouble

[wesacosa]

1 minute ago, grogee said:

You can do it @wesacosa! You're already braver than 75% of so-called 'mechanics' by owning, driving and fixing an old Citroen.

Methodical, take time, take pictures, label or write down fixings. 

A man (or woman) made it, so another man can repair it. 

cheers. if it was any other component with that level of change I'd have done it already but HP diesel pumps give me the chills 

[N Dentressangle]

3 hours ago, grogee said:

Methodical, take time, take pictures, label or write down fixings. 

The way a mobile phone allows you to take pics as you go has saved my bacon on many occasions. These days I take as many pics as poss - it's amazing how useful they are when you realise that thing you removed could go back the other way round.

[wesacosa]

Back on the XM today after it wouldn't start the day of the South East meet-up last month.  As suspected it was a combination of a slightly low battery and the crappy negative earth connector. I cut the connector off and fitted a new one as I had previously the positive lead. Its not so easy as the cables are really thick and there are multiple ones but managed to find a suitable one.  Few pumps of the primer bulb and as usual it fired up first time 

I decided look so start clearing around the pump area to have a look at replacing the faulty O rings but the leak I described previously on the top solenoid doesn't seem to be the main one. Something is dripping out of sight and running down the pump body. There is a weep from the top solenoid when running but when not running and when I squeeze the primer bulb there is a bigger leak somewhere else

Its running down where the yellow marker is but it's not coming from the valve above as first though 

It could be from seal 606  suppose but I think more likely 607/690 as it's coming from high I think and I guess 606 would likely drip lower down

The trouble is I'm not sure how easy it is to get to 607/690 with the pump in situ due to the loom connector and some plastic covers which don't seem to be removable without disconnecting the feed pipes on the pump

So next steps? Well as I'd feared the pump probably does need to come off. I don't know how easy this is. It can be removed without disturbing the cambelt. Haynes does say the aux belt and mount need disconnecting but I can't see why as on mine at least the front cover around the pump sprocket is a separate piece and thats the only reason I would imagine you'd need to remove those bits

The trouble is I just don't know if I can be bothered anymore. Given its a running, driving, MOTd concern at the moment and there is a chance after my cack handed interventions at least two of those may no longer be true I wonder if its better to just leave well alone and let the next owner have a go. According to the French car forum it's not too bad a job to do the seals and much easier than a mechanical pump. 

Its not even as if I am going to use it once it's fixed due to ULEZ and too many other cars. 

So whilst I think what next I might be amenable to slightly derisory offers so long as they are not too derisory 

 

[wesacosa]

I didn't get the Panda finished in time for an MOT so had to press the XM back into service for the Super Touring Power pre 2000s car parking at Brands over the weekend. To be honest it probably was more appropriate for an event celebrating 90s saloon cars anyway 

I have only driven it twice since August, once for its MOT in Feb then a week later to work when there was a car problem elsewhere 

A few pumps on the hand primer and it fired instantly and rose up to height.  I had been stressing all night about driving it, as seems to be the way with me at the moment given a number of FTPs across the rest of the fleet, but all was well

The fluctuations in revs that had come on my last two drives in August and again in Feb seem to be quite consistent now. They happen about 5 mins into a journey and last for about a minute then clear. I suspect that the leak on the pump must be somewhere that becomes critical at the point of maybe going from a cold fuel pump strategy to a warm one .

The XM did get a few nice comments but no response to my advert in the window as of yet, although I wasn't expecting too much on that front as it was very half arsed

It has inspired me to put the advert back up on Facebook/club XM and french car forum though 

A pleasant sunny weekend with the car celebrating my favourite period of Motorsport would be a really fitting way for my custodianship to come to an end

[wesacosa]

Someone replied to my Facebook for sale advert to say they had a similar issue as mine on their Lucas EPIC pump Peugeot (revs hunting) and it was the coolant temperature sensor. I looked on some of the Citroen forums and a few other people had it too.  Not getting too hopeful just yet but the rev hunting symptoms did come a fair while after the fuel weeping so maybe something in it.  I've ordered a new one so lets see

[wesacosa]

having not really driven the XM since last August its now been to its second show in a few weeks with the FotU this weekend 

As per the previous post I was tipped off that the rev hunting may be due to the coolant temperature sensor which does provide the reading for the EPIC pump control on these.  I fitted a new one last weekend. Drove it around the block on Thursday night and then on some longer test runs on Friday and no sign of issues so bit the bullet and took it the on the 240 mile round trip yesterday. Thats now 5 journeys where its not exhibited the issue now (The last 8 journies it did it on 6).  The reason I'm not yet calling it fixed is that it seems to be quite specific time in the jouney it does it and only when you come off throttle or are at idle so maybe I missed the window but the odds suggest its at worst "improved" and at best "fixed"

I wasn't with the car much at FotU as there was so much to see but every time I passed it there were people looking at it which was nice.  Still nobody seems to want to buy the fecker though 😂

 

[wesacosa]

I decided to have a further look at the where the air might be getting into the fuel system as I am coming around to the idea that the O rings, whilst leading to small fuel weeping especially in winter, are perhaps not the source of the other running issues.  Having already seemingly improved/fixed (?) the rev fluctuation with the temperature sensor I thought I'd take a look at where the air bubbles in the fuel are coming from 

from this video after a 2 day lay up you can see it starts easily and quickly but there are bubbles in the clear pipe from top of the filter to the pump, but also less frequent but bigger bubbles in the lower clear pipe which is part of the pipework from tank to fuel filter/lift pump (post priming bulb) so air is getting in somewhere from tank to that clear inlet pipe 

Today, after leaving it for 2 weeks, I took the rubber hoses from the bulkhead inlet pipe , through the primer and to the plastic joiner where the rubber hose meets the clear inlet hose (marked with the red arrow) and everything to the left/tank side/downstream of the arrow was bone dry, and everything to the right/pump side/upstream of the red arrow had fuel in, so clearly fuel is draining back down to the tank from the red arrow backwards.  As I understood it the bulb should have a one way valve in so that maybe isn't working but I guess there is maybe another issue somewhere to.  Not hugely up on how it all works but I thought the lift pump pulled fuel up under vacuum and then that vacuum keeps fuel in the pipes when the engine is off but I guess maybe there is an air leak somewhere downstream of the red arrow meaning that section doesn't hold vacuum.  As to why the upstream pipes dont lose fuel, maybe it's the shape of the first rubber pipe downsteam of the red arrow ?  The Citroen pipe is a preformed S bend pipe which turns sharply out of the plastic connector and runs flat to the primer but this had a hole when I bought the car so.with just a straight section of hose all I could do was have the high gradually up and down bend to the primer 

 

 

[wesacosa]

got around to putting the clear pipes on over the weekend

So as well as the bubbles in the factory clear pipes we have this

 

 

There seems to be a big air bubble trapped post primer alongside the smaller bubbles, there are also a collection of bubbles at the entrance to the plunger

 

As soon as the engine goes off you can see the fuel draining back down from the tank side of the primer

Not sure if the cluster of bubbles is due to the fitment of the plastic pipes and clips but they did seem tight but does suggest an air leak somewhere from tank to engine bay 

[richardmorris]

I’m not up to speed on this thread, but have you replaced the fuel filter holder / primer? My turbo diesel CX was sucking in air and it took a long time  to find out where. First replaced all the pipes, then cut out the pre-heat block unit, then finally the primer.

[wesacosa]

28 minutes ago, richardmorris said:

I’m not up to speed on this thread, but have you replaced the fuel filter holder / primer? My turbo diesel CX was sucking in air and it took a long time  to find out where. First replaced all the pipes, then cut out the pre-heat block unit, then finally the primer.

These are the later ones with the remote primer bulb which apparently are not as troublesome, plus I think the air is getting in downstream/tank side of the fuel filter as there are bubbles in the factory fitted clear pipe downsteam of the filter housing..

[richardmorris]

16 minutes ago, wesacosa said:

These are the later ones with the remote primer bulb which apparently are not as troublesome, plus I think the air is getting in downstream/tank side of the fuel filter as there are bubbles in the factory fitted clear pipe downsteam of the filter housing.. Downstream suggests the problem is higher up?

[wesacosa]

20 minutes ago, richardmorris said:

37 minutes ago, wesacosa said:

These are the later ones with the remote primer bulb which apparently are not as troublesome, plus I think the air is getting in downstream/tank side of the fuel filter as there are bubbles in the factory fitted clear pipe downsteam of the filter housing.. Downstream suggests the problem is higher up?

never sure of my ups and downstreams.  I think the issue is between the filter housing and tank not the filter housing and engine 

[Noel Tidybeard]

are there any jubilee clips? that should be your 1st call- they're not fit for pyrpose on a diesel fuel system

[wesacosa]

5 minutes ago, Noel Tidybeard said:

are there any jubilee clips? that should be your 1st call- they're not fit for pyrpose on a diesel fuel system

The proper pipes have R clips but the clear hoses I fitted for testing have the fuel pipe clamps not jubilee clip

[Lankytim]

I’m also not up to speed on this thread but leaks on the pump in my 2.5TD were caused by air in the diesel entering the pump. Don’t ask me why but stopping air getting in via leaky pipes stopped the leaks.