Xsara fuel filter

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deejay
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Xsara fuel filter

Post by deejay »

Have recently changed the fuel filter on my 110 Hdi Xsara and found some swarf in the bottom of the filter. I took it off and cleaned it out but I am concerned about this as I have read on the Forum that the in-tank pumps fail and fill the HP pump with swarf. Anybody got any suggestions? Should I panic! It has been serviced by a main dealer up till now so nuff said. The car has done 42,000 miles and is running fine, at the moment!
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AndersDK
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Post by AndersDK »

I believe that many owners aware of the HDI pump problems simply fitted an extra filter same kind into the fuel line from the tank pump.
You may fit it in an easy to reach location in the engine bay.

Thats about the cheapest insurance you can buy yourself.

Note : do not use the old & cheap type carb filters, which can not withstand the lift pump pressure. Any inline alucan petrol injection engine fuel filter will do. They are used in most PSA petrol injection cars. Cost some £10.
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deejay
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Xsara fuel filer

Post by deejay »

Thanks Anders. Do you know what sort of pressure the lift pump operates at? Will try to fit another filter in the fuel line at the back of the engine where there is some spare room. Not much room under the top cover for anything.
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AndersDK
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Post by AndersDK »

Dont worry on the pressure. Thats just the lift pressure which I presume is in the order of approx 0.8bar, as this is the working pressure for petrol lift pumps in general.

The filter type I mentioned, is the standard Citroen (PSA) petrol injection filter. Approx 2.5" dia by 3.5" lenght, with 6mm studs each end. Its also used in multipoint petrol engine systems, which runs off a 3bar lift pump pressure.
It will therefore readily withstand your HDI low pressure side fuel system pressure.

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thorter
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Post by thorter »

It is not clear whether it is possible to add an effective additional filter in the hdi fuel system. Piecing together the specifications for the fuel supply chain from odd bits of info (mostly Peugeot), I find the following.

The Tank Lift Pump output pressure limits are between 2.2 & 3.2 bar.

Pressure at the Bosch filter unit input is quoted as 2.0 to 2.5 bar.

Regulated output pressure of the Bosch filter unit is 1.0 to 1.5 bar.

The High Pressure Pump appears to have a valve that requires more than 0.8 bar before fuel is passed to the high pressure stage, otherwise injection is stopped and all the fuel is returned to the tank.

So, if a 2 to 5 micron filter is to be added (the existing Bosch filter is claimed to be 5 micron), there is not much margin for an additional pressure drop in either the pipe from the tank to the filter or the filter to HP pump line.

Has anyone successfully added such a filter?
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Post by nick »

The question really is how much of a pressure drop would be caused by a filter fitted between lift pump & original filter, under load. Personally I doubt it would be enough to cause a problem, after all the original filter is regulating the pressure down to around half what it is receiving from the lift pump. (It does this variably with a sort of spring & ball bearing arrangement, so should be able to compensate for the inlet pressure being lower)
You may find that if the extra filter begins to clog it will cause the engine to refuse to start, this may not be an entirely bad thing however !
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Post by thorter »

Yes, it is likely you would get away with an extra filter, certainly for starting or at light load, since flow rates are low. Any limitation would be at maximum flow near full load.

However, the implication of the pressure tolerance ranges is that the current filter could drop something like 0.5 bar at maximum flow. A finer filter might well drop more, and needless to say, there is little point in adding a filter worse than 5 micron.
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Post by AndersDK »

Honestly guys -

With the pricetag on a HP pump repair, whats the reason to discuss if the fuel inlet pressure would drop another 0.1-0.2 bar - even less ?
Go on and fit that filter shown (its a large filter with known large throughput). I really cant think of a cheaper insurance.

The filter should be fitted inline on the fuel line from tank to first filter - to be sure you dont introduce new swarf alone by the fitting job.
Like deejay suggests.
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deejay
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Xsara fuel filter

Post by deejay »

Thanks for all the comments gents, much appreciated. Will now go and get a filter and some jubilee clips and have a go at fitting it at the weekend. Seems like an obvious and simple solution. Will let you know how I get on!
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Post by nick »

Out of curiousity deejay, how much swarf did you find?

I've just changed the filter on my Xsara this morning and found a small quantity of tiny (just visible) metal fragments in the bottom of the filter bowl. To be honest though, no worse than I used to get in the filter of my XUD engined Xantia sometimes.
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Post by MikeT »

That's what I found when I first changed my filter - looked like a sprinkling of glitter at the bottom of the housing.

After running on cooking oil for several hundred miles I took the advice off this forum and changed the filter again but there was no swarf this time. I also dissected the filter and found it generally clean.
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Xsara fuel filter

Post by deejay »

It was a bit like MikeT's description of a 'sprinkling of glitter'. It probably covered about 50 per cent of the base of the bowl, but it was spread out, not all together. Difficult to describe really, but definitely easily visible. Where does this come from, is it the lift pump wearing, or is there another answer. If Nick found this in the filter bowl of his XUD engined Xantia, where did this come from as the XUD doesn't have a lift pump, does it? According to the service records (main dealer) the filter was changed at 32000, but can't see the garage taking the filter bowl off to clean it out though. Mileage now 42000.
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Post by MikeT »

Right from the refinery, your fuel is contaminated although it's probably filtered at certain points of transfer as well. It's been through several storage tanks before it reaches yours.

I wouldn't worry about where it comes from, I'm satisfied it remained in the housing and didn't go any further.

I would imagine all parts in the fuel system wear and deposits will be created. With Xantia's I've read it could indicate lift pumps, with VW's I've read it could indicate injectors.

As I got the opportunity to re-inspect the housing shortly after filter change (a few hundred miles) , I'm happy that whatever the glitter was, it isn't continuing to appear. I would suggest you do the same to put your own mind at rest.
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Post by nick »

It has been suggested that this can come from filling station pumps.

If it was covering 50% of the base of the bowl that does sound a bit worrying. Have you heard any strange noises from the lift pump?

Main dealers are certainly supposed to give the plastic housing a very thorough clean before the new element is fitted, I just put a complete new housing on as I'm not convinced in my own abilities to clean the old one well enough!

I had a good look at the old housing and element I took off, and it is very hard to imagine how anything other than absolutely microscopic fragments could get past the filter. 2001> HDi's do also have an improved filter housing. All I can think is if the element got very badly clogged, then it might be just possible for something to find its way past the seal between the plastic stub in the bottom of the bowl and the inside of the filter cartridge. I wonder if part of the problem is that the filter change intervals are just too long? I've always changed the diesel filter annually on my cars regardless of what the manufacturer says.

If you put an additional filter on it could be worth changing it again after 6 months or so, and opening it up to see if its caught any more fragments. I'm not sure how easy it would be to open one of these metal cannister filters without hacksawing it though?
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Post by deejay »

Have not heard any strange noises from the lift pump, it just makes a low volume hum when you turn the ignition on, but it sounds OK to me.

What happens when they pack up, do they become noisy or is it that they just stop working? I think I will run it for a few more miles and do as suggested, take it out again to see what is happening.

Will still put another filter in the fuel line though as has been recommended.
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