S1 Xantia 1.9TD - Engine running very erratically

[pete the bus]

Try temporarily replacing the leak off pipe from the last injector to the pump with clear polythene pipe to see if that's where the air is coming from.

Just noticed this.
Something else I haven't tried. Will give it a go and report back.

[citroenxm]

The Return Banjo is at the end of the metal pipe that this return pipe push's onto on the side of the pump..

Remove the 17mm (or is it a 16mm) bolts in the side, recover or catch the copper "Seals" and remove the banjo..

CAUTION: when refitting, make sure a copper washer is on each side of the pipe return when you place it all over the banjo bolt. DO NOT tighten excessivly, as this can "Tear" the banjo bolt across the bore..

Theres a gause in that return...

[pete the bus]

Thanks.
Is it the gauze that can get clogged up, or the hole in the banjo itself?

[citroenxm]

Possibly both.... needs to be clear from what CitroJim has put..

[pete the bus]

Thinking about it, I guess that if I've already run a tube from the injector return into a bottle and fuel was flowing quite freely then it would suggest the banjo hole and gauze was clear?
Still, I'll have a check tomorrow, as well as putting a clear tube onto the injector to pump leak off point...

[CitroJim]

Easy Pete, remove it and blow through it. You'll see the small hole in the side of it. The return banjo may hide behind a big hex head...

Also, there should be a fine filter gauze behind it that can become choked up too...

If that fails to bring relief then you're going to have to do the ultimate test and that's to hook up a temporary test tank above the pump to eliminate once and for all fuel supply issues...

Get a container that will hold say half a gallon of diesel and arrange for that to be suspended from the bonnet with a pipe running directly to the pump inlet. Everything must be utterly scrupulously clean as you'll be running filterless.

If the engine now runs lovely then you know engine, pump and injectors are happy and your fault is with the fuel supply...

[Old-Guy]

Thinking about it, I guess that if I've already run a tube from the injector return into a bottle and fuel was flowing quite freely then it would suggest the banjo hole and gauze was clear?

In a word, no. The whole leak off system needs to be under suction from the pump to check if there's any air being sucked in. One end of the last leak off pipe pushes onto the last injector and the other onto a steel pipe which has the banjo fitting on its other end (at the pump). If you leave this open, you introduce a MASSIVE air leak

You need to do as Jim says and check the banjo and gauze are clear and that you can blow bubbles back into the tank via the main return pipe.

If you haven't already done it, check the tank filter! No apologies for repeating this - it's a well known problem and your symptoms point to a clogged tank filter. Now I've got my newly acquired VSX on the road, it too needs this checked, even though its fuel starvation (air ingress) problem has gone away - probably only temporarily.

[pete the bus]

Easy Pete, remove it and blow through it. You'll see the small hole in the side of it. The return banjo may hide behind a big hex head...

Also, there should be a fine filter gauze behind it that can become choked up too...

If that fails to bring relief then you're going to have to do the ultimate test and that's to hook up a temporary test tank above the pump to eliminate once and for all fuel supply issues...

Get a container that will hold say half a gallon of diesel and arrange for that to be suspended from the bonnet with a pipe running directly to the pump inlet. Everything must be utterly scrupulously clean as you'll be running filterless.

If the engine now runs lovely then you know engine, pump and injectors are happy and your fault is with the fuel supply...

As already stated in earlier posts I have done the 'ultimate test'! Engine still rough.
Also as previously stated I have connected a pipe to the pump banjo connector and a good amount of fuel was seen to be flowing through it, I presume therefore indicating that the gauze and hole are clear?

Assuming the pump is in good working condition, would pump timing affect the running as described?

[pete the bus]

Thinking about it, I guess that if I've already run a tube from the injector return into a bottle and fuel was flowing quite freely then it would suggest the banjo hole and gauze was clear?

In a word, no. The whole leak off system needs to be under suction from the pump to check if there's any air being sucked in. One end of the last leak off pipe pushes onto the last injector and the other onto a steel pipe which has the banjo fitting on its other end (at the pump). If you leave this open, you introduce a MASSIVE air leak

You need to do as Jim says and check the banjo and gauze are clear and that you can blow bubbles back into the tank via the main return pipe.

If you haven't already done it, check the tank filter! No apologies for repeating this - it's a well known problem and your symptoms point to a clogged tank filter. Now I've got my newly acquired VSX on the road, it too needs this checked, even though its fuel starvation (air ingress) problem has gone away - probably only temporarily.

I meant I had connected a pipe up from the injector PUMP, not the injector - sorry. The pipe outlet which returns fuel to the tank - it is working perfectly well.
And as I have done the 'ultimate test' (see citrojims post above) of connecting a container of fuel directly to the pump inlet, this rules out any blockage, leak, or other problems upstream of the pump.

So, it must be a pump or injector problem, or pump timing, no?

[CitroJim]

Assuming the pump is in good working condition, would pump timing affect the running as described?

It can but it would be constant...

One thing that should be made clear is that the pump relies on a very high volume of fuel to pass through it and if this volume cannot be maintained due to say, a choked strainer then the level and pressure of fuel in the pump body may fall below that required and will give rise to the problems. At all times, even though only a tiny fraction of it is ever injected, the pump body (about a pint) must be maintained completely full and at a pressure of several bars - the transfer pressure - without these conditions being met and maintained the fuel cannot efficiently fill the high pressure pumping element and give a clean, coherent delivery of fuel through the injectors. It only needs for the fuel flow through the pump to fall a little or become aerated just a little for problems to arise.

Also, the fuel transfer pressure in the pump body also drives the timing device hydraulically. If the transfer pressure is low or the fuel is full of air then the pump will not advance properly and your symptoms point to this - that it's running rather retarded.

Retarded timing will cause hard starting, smoke, poor power and a very 'quiet' running engine with absolutely no life in it.

Pete, have you tried the temporary tank as I suggested earlier? That's the real ultimate test.

[CitroJim]

And as I have done the 'ultimate test' (see citrojims post above) of connecting a container of fuel directly to the pump inlet, this rules out any blockage, leak, or other problems upstream of the pump.

So, it must be a pump or injector problem, or pump timing, no?

Pete, ignore my post above apart from any interest value it may have. I submitted it just before I saw your latest. Sorry..

Yes, if you know the return pipe is clear and the banjo is good then the pump or injectors it is. More likely the pump.

I would suspect now either a plunger spring is broken or something is badly gummed up and stuck... If it's ever run on veg or it was sitting unused for a long time on the dealers forecourt - very possible.

The pump is quite amenable to being overhauled at home. See my website...

[pete the bus]

Thanks Jim, looks like I will be needing to remove the pump, then. I understand I will need to lock the timing first as per a belt change, and I will need a special spanner to get to one of the bolts. Can someone point me to a piccy of the sort of spanner I will need please?
Also, could I fit a pump from a scrapped car (assuming it's a similar pump) without too much trouble?
Many thanks for everyone's input so far, it's all very useful learning experience.

[CitroJim]

Pete, you need a half-moon 13mm ring spanner to get the lower flange nut off tthe pump and it's fiddly evven then..

Basically lock the crank, cam and pump sprockets as if doing a cambelt but you don't actually need to remove the belt as long as you use two pins (8mm studs) in the pump sprocket.

Loosen and remove the pump sprocket nut (21mm)

Disconnect and remove the injector delivery pipes, disconnect all other pipes and cables.

Loosen the three pump flange nuts but don't remove them all just yet although you can remove two... Don't loose the special washers

Use the special puller - details later - to break the taper on the pump drive sprocket.

Loosen and remove the the back mount nut, bolt and special washers.

Stuff lots of rag around the sprocket.

Remove the last flange nut and washer. Pull the pump gently backwards, watching for the woodruff key on the drive shaft. That's why you stuff loads of rags around as it has a habit of making a bid for freedom..

You can now remove the pump.

You will need this puller:



This is the plan to make one:



This is the puller in use (engine removed for clarity):



Hope that is enough to get you going Pete...

Any more questions, just shout..

[CitroJim]

PS. Bolts for the puller can be borrowed from the gearbox!!!

[citroenxm]

If its pump removal time, then the cam belt doesn't need to come off.. and once locked, Being a bit "Ham Fisted" there is no need to make a puller either..

As for the "3rd" 13mm bolt under the pump, theres an easyer solution, If you slacken the 22mm bolt through the altinator, and then undo the upper 13mm Altinator Securing Bolts, swivel the altinator Forwards, this then releases LOADS of space for a standard spanner on the lower bolt. Theres NO need to alter the Aux belt tension either..

Once the three 13mm nuts are off, and the 4th nut from under the Injector pipe outlets on the back of th pump, I actually use a screw driver on the top of the pump between the back plate and pump, and it pops away from the pully.. Recover the key way, it may drop into the pump pully... but no further.