Setting the timing on a late 1.9TD Xantia

[Dommo]

Hi all.

We recently had a Bosch pump refurbished on one of our Xantia's, it's a later 97 car with the pump that has the potentiometer, third injector wiring, and vacuum controlled warm idle. I was under the impression that retiming these pumps was a case of setting it til it sounded clattery, and backing it off slightly from there, but I'm not sure I'm happy with that idea. It seems to sort of set the timing itself, presumably using the third injector sensor? Without the proper tool what is the best way to time these up? Do you need to disconnect the third injector before messing with it? As it stands we've basically retimed it to precisely where it was before we took the pump off.

The issue we're finding is that it starts very strangely, it's quite sluggish to fire, taking a couple of seconds of cranking, and it's very quiet (not clattery) when it does fire. It soon picks up with the clattering after a second or so, at which point it sounds like a proper XUD again. So, is it currently set too retarded, and the pump is compensating and advancing the timing once it starts up?

What is the best course of action here, the assumption we're making is that the timing is wrong, do we all agree?

Thanks all, Dom.

[Dommo]

Sorry to 'bump' the post but we still haven't properly set the timing here. Any ideas folks? Thanks very much

[CitroJim]

I was under the impression that retiming these pumps was a case of setting it til it sounded clattery, and backing it off slightly from there, but I'm not sure I'm happy with that idea.

That's how I've always done it Dom!

It sounds like it's starting up very retarded. A dead giveaway is that it's running very quietly.

The AS3 pump naturally fails fully retarded as a failsafe if it looses its electronic control.

For good starting and cold running the pump needs to be set to cold advance. It appears this is not happening.

You need to check the third injector Needle Lift Sensor is working. disconnect it with the engine running at normal operating temperature and you should hear a distinct change in note. If no change then the Needle Lift Sensor may be duff. It should show a DC resistance of about 100 ohms.

If that's inconclusive, you will need a Lexia session to see if the pump is responding to timing commands from the ECU. Lexia may show stored faults too.

Lots more advice on offer here if needed

[RichardW]

As I recall setting the timing involves a dial test indicator, can't remember the specifics, nor how it integrates with the needle lift sensor!

[Dommo]

Thanks guys.

We've already played around with Lexia and it does seem to make all the different changes as you'd expect it to when you ask it to alter idle and timing and whatnot. So I think it's electrically working perfectly.

What we found a bit odd when trying to alter the timing is that it wasn't seeming to make a big difference to the sound it was making despite making fairly large timing adjustments with the pump, is the pump adjusting itself to combat what we were doing? What's the best way to set the timing here Jim? Do we disconnect the 3rd injector to force the pump fully retarded, and then set the timing manually there to make it as clattery as we can? Sorry for all the daft questions, we just have no experience with the auto adjusting pumps like these.

Thanks ever so much, Dom.

[CitroJim]

I will consult my documentation Dom

[CitroJim]

Indeed Dom, it sounds like the system is compensating as you rotate the pump.

It suggests that part is all in good working order and the needle lift sensor is doing its job.

As it's all been disturbed, the first checks you need to make are on cambelt timing. The symptoms are very reminiscent of being one tooth out. Lock up crank, pump and cam with index pins - don't try to do it 'by eye'.

Also, if you have had the pump sprocket off, check the woodruff key is present and correctly seated; they are very good at making a bid for freedom when the sprocket is refitted.

The electronic timing can be disabled for test purposes by disconnecting the ECU...

[Dommo]

Indeed Dom, it sounds like the system is compensating as you rotate the pump.

It suggests that part is all in good working order and the needle lift sensor is doing its job.

As it's all been disturbed, the first checks you need to make are on cambelt timing. The symptoms are very reminiscent of being one tooth out. Lock up crank, pump and cam with index pins - don't try to do it 'by eye'.

Also, if you have had the pump sprocket off, check the woodruff key is present and correctly seated; they are very good at making a bid for freedom when the sprocket is refitted.

The electronic timing can be disabled for test purposes by disconnecting the ECU...

Thanks for this Jim.

I don't *think* we have the pump timing out, but of course we can check that. The woodruff is a possibility, we have a borescope (of sorts) so hopefully we should be able to check that with the borescope and confirm the key is there, as it was a bit of a pain getting the pump refitted while keeping the woodruff key in place!

Regarding disabling the electronic timing by disconnecting the ECU, if we do this, are you ever able to somewhat set the pump timing by ear or will it always be far too retarded on timing for it to ever sound correct?

Lastly, I spotted a post of yours from a while back where you mentioned creating a timing tool for these AS3 pumps using a lathe, I don't suppose you have the information regarding that do you? Ie what needs to be made for the tool to time it the 'official' way? See this post for what I'm talking about here:

Static timing must be set as Liquid advises above. The pump should be timed by use of a Dial Test Indicator but unless you have the correct special tool or are willing to make on on a lathe it's not viable but happily you can do it by ear...

(It's the 5th post on this thread)
viewtopic.php?t=73224

Thanks Jim!

[CitroJim]

I don't *think* we have the pump timing out, but of course we can check that. The woodruff is a possibility, we have a borescope (of sorts) so hopefully we should be able to check that with the borescope and confirm the key is there, as it was a bit of a pain getting the pump refitted while keeping the woodruff key in place!

A bit of a pain is an understatement Dom! It's made difficult as the pump is just coming up onto one of its four 'compressions' at the point and it can so easily flip and send the key flying... I used to use lashings of Vaseline and stuff the surrounding area with rags to catch any errant keys...

Regarding disabling the electronic timing by disconnecting the ECU, if we do this, are you ever able to somewhat set the pump timing by ear or will it always be far too retarded on timing for it to ever sound correct?

Yes, the pump will be fully retarded and you could try setting it so that the engine note is very soft and with the absolute absence of any diesel knock. Then reconnect and see it if then sounds about right...

Always disconnect/reconnect with the battery disconnected...

Lastly, I spotted a post of yours from a while back where you mentioned creating a timing tool for these AS3 pumps using a lathe, I don't suppose you have the information regarding that do you? Ie what needs to be made for the tool to time it the 'official' way? See this post for what I'm talking about here:

Static timing must be set as Liquid advises above. The pump should be timed by use of a Dial Test Indicator but unless you have the correct special tool or are willing to make on on a lathe it's not viable but happily you can do it by ear...

(It's the 5th post on this thread)
viewtopic.php?t=73224

Thanks Jim!

Hang on in there Dom, I'll go and do a bit of re-familiarisation - it's been a while since I've done anything in this area and I need to get back up to speed

[CitroJim]

Lastly, I spotted a post of yours from a while back where you mentioned creating a timing tool for these AS3 pumps using a lathe, I don't suppose you have the information regarding that do you?

This may well help Dom:

This is the Laser Tools DTI Timing Kit:

It shows quite nicely how they are made and includes brief notes on how to use it. The guidance is NOT specific to an XUD 1.9TD but rather generic for any engine having a VE type pump.

Indeed, It would not be hard for a competent engineer to knock one up on a lathe... They would need a pump by their side to do so though...

Making one 'blind' would be tricky...

And this is is quite a comprehensive procedure from the XUD Diesel Engine BoL to time a 1.9TD using a DTI:

The setting should be around 0.66mm

You might need to do a bit of zooming on those images to make them fully readable

Hope that helps a bit...

[Dommo]

Sorry to resurrect an old post here but we are having new issues with the pump now!

For seemingly no reason the car started idling correctly. We’d set the timing somewhat in the middle of the adjustment range and found that it would fire up perfectly and ran beautifully. We took it for an MOT and it passed so that was great news. When we got back we found the AC pump had failed and was partially stuck on, despite no gas, so as an aside we need to get a new AC pump… this meant the car was parked in our garage for another month.

Fast forward to today, now the car barely starts again and runs very badly but luckily for us it threw a check engine light. This showed up a permanent adjustment of motion fault (which switched to intermittent when we turned the car off and on again).

Any thoughts on what we should try here ?

Last time we checked the belt timing was fine, so we are assuming no change here.

Thanks all, Dom.

[CitroJim]

Fast forward to today, now the car barely starts again and runs very badly but luckily for us it threw a check engine light. This showed up a permanent adjustment of motion fault (which switched to intermittent when we turned the car off and on again).

Any thoughts on what we should try here ?

Hi Dom, pleased the car MoT'd and was OK bar the A/C pump

Yes! Been here a few times before... The timing adjustment relies upon enough fuel pressure being available in the pump to operate the mechanism. The pump uses its own diesel under pressure generated by the low pressure pump as a hydraulic medium to position the timing cam...

The usual cause of this fault being raised is fuel starvation due to either air leaks in the pipes between tank/filter/pump or blockages/obstructions. The latter can be caused by a plugged fuel filter or a blocked fuel strainer in the bottom of the fuel tank... They often, over time, grow and impressive coat of slime which restricts the flow considerably...

The strainer can be got at by lifting the back seat, removing the big rubber bung above the tank, unscrewing the big collar around the top of the fuel gauge sender unit and lifting it out. The strainer is a plastic mesh bag attached to the bottom of it...

Also check the integrity of the leakoff pipes...

[Dommo]

Fast forward to today, now the car barely starts again and runs very badly but luckily for us it threw a check engine light. This showed up a permanent adjustment of motion fault (which switched to intermittent when we turned the car off and on again).

Any thoughts on what we should try here ?

Hi Dom, pleased the car MoT'd and was OK bar the A/C pump

Yes! Been here a few times before... The timing adjustment relies upon enough fuel pressure being available in the pump to operate the mechanism. The pump uses its own diesel under pressure generated by the low pressure pump as a hydraulic medium to position the timing cam...

The usual cause of this fault being raised is fuel starvation due to either air leaks in the pipes between tank/filter/pump or blockages/obstructions. The latter can be caused by a plugged fuel filter or a blocked fuel strainer in the bottom of the fuel tank... They often, over time, grow and impressive coat of slime which restricts the flow considerably...

The strainer can be got at by lifting the back seat, removing the big rubber bung above the tank, unscrewing the big collar around the top of the fuel gauge sender unit and lifting it out. The strainer is a plastic mesh bag attached to the bottom of it...

Also check the integrity of the leakoff pipes...

Brilliant, thank you Jim.

We'll get onto that this coming week hopefully then! It's had a new fuel filter recently as it happens, so potentially a bad seal with the housing, or at the very least a potential bad filter. It was an OE one mind you so you'd hope it was decent. But the problematic running does tally up with a recent filter change.

Any suggestions on air con compressor refurbishers? Unlikely but worth an ask!!

Thanks again, Dom.

[CitroJim]

Any suggestions on air con compressor refurbishers? Unlikely but worth an ask!!

'Fraid not Dom although I do hope someone can advise

[mickthemaverick]

You could try these guys Dom, they did one for my neighbour and it was fine: https://automotivecompressor.co.uk/