Is this terminal?

rory_perrett · Unread post by **rory_perrett** » 07 May 2006, 21:16

My beloved Xantia 2.1TD Exclusive is not well. Citroen electrical gremlins stuck yesterday meaning the cooling fans didn’t come on while stuck in traffic. Water temp hit 120 deg and the oil temp probably that and a bit more. Seemed OK once on the move and the temps came down. However afetr it had been standing for a few hours all does not seem well.

The symptoms are

– sounds really clattery, very dieselly, like an old transit van.
– Its down on power, particularly noticeable on hills when it won’t pull as normal especially from low revs, better once the range at which the turbo comes in , will maintain 70mph on motorway
– Significant black smoke out of the back, seems to be especially when under load and at lower revs 1500 – 2000rpm.
– No water loss, no obvious emulsion in oil
– Seems to be running slightly hotter, particularly the oil temp, only a few deg.

Any suggestions guys?

Dave Burns · Unread post by **Dave Burns** » 07 May 2006, 22:12

Could be that the ecu's temp sensor has let go in the heat, you need to know what its doing against what it should be doing.

Can you feel any hunting even the slightest, if so it could mean head gasket cylinder to oilway failure.

Dave

rory_perrett · Unread post by **rory_perrett** » 07 May 2006, 22:20

Dave

No, no hunting - the tick-over is steady it is noisier and there is possibly slightly more engine vibration.

Unread post by **Peter.N.** » 07 May 2006, 22:23

The usual problem with XUD engines overheating is failure of the head gasket or the head itself, but the 2.1 has a completely redesigned head with the main aim of improving the cooling efficiency and I havn't heard of one that has failed yet! So thats the good news.

If its not blowing water out of the overflow or has water in the oil or oil in the water the head should be OK. I believe yours is ECU controlled, I have only had experience with it in the XM and they have all had mechanical injection.

If it does have an ECU it could be as Dave says a sensor thats packed up. If its mechanical it sounds like a timing problem, is it possible that the cam belt has slipped a tooth under the very hot conditions

Ian Fearn · Unread post by **Ian Fearn** » 07 May 2006, 22:24

This sounds to me more like a sensor failure and the engine is no longer running within the conditions of the ECU.

Do you have an extra lights on your dash?

rory_perrett · Unread post by **rory_perrett** » 07 May 2006, 22:35

Well if nothing else I'm feeling a bit happier.

It is ECU/ fly by wire so I was kind of hoping it might be a sensor. The engine systems warning light is not on on the dash.

The timing being slightly out could explain why it sounds more dieselly and the black smoke suggests over fueling which again could be the result of a confused ECU.

So do I go to a diesel specialist or is it a trip to a Citroen dealer so they can plug in their diagnostic kit?

deian · Unread post by **deian** » 07 May 2006, 22:40

I have the same engine in my xantia, so i'll be following this thread.
Don't Forget: to fix the cause of the problem once you've established why it's running badly, hopefully it's a sensor, but next time it could wreck havoc. Good luck.

rory_perrett · Unread post by **rory_perrett** » 07 May 2006, 22:50

Yep! Got one of the fans working already but I suspect the other needs a bit of a rewire. The fault is with the 3 relays that sit between the 2 fans. The 2 realys that are for the fans (I assume the other switches them between series and parallel to give the different speeds) and the holders they plug into just do not appear to me up to the job. There are clear signs of overheating (deformed and melted plastic and blackened contacts).

Not sure how long they haven't been working as the car rarely spends any time in traffic.

Check yours still work before summer.

deian · Unread post by **deian** » 07 May 2006, 22:57

aye mine definately work, i changed the coolant last weekend and the big test was seeing if the fans stabilise the car, and they came on no problem, so i'm all set for the summer now,

it's horrible having a car overheat, it happened to my old escort on a hot summers day on a motorway, i was NOT impressed, thankfully i was in a motorway works area and i got a free breakdown towtruck, and they guy was nice enough to jump my fan connections, and wire a switch through the window so i can swith it on if it goes too high, 8)

NiSk · Unread post by **NiSk** » 07 May 2006, 23:05

Try just disconnecting the battery for a few minutes (afer checking that you have the code for the stereo!) and see if the EECU resets itself.

//NiSk

AndersDK · Unread post by **AndersDK** » 07 May 2006, 23:26

I've had a look on Citroen PR-net on the XUD11TE on the thermostat housing carrying the fuel filter.
Apparantly there are a few options for sensor fittings according to a/c or not and some other options I'm not familiar with.
But 3 sensors are possible to be fitted to the thermostat housing :
1 by itself (inwards towards engine) - and/or 2 side by side on the other side of the filter housing.
One sensor should be blue. This would be a 2-pole temp sensor.

Check it out by unplugging it - and then shortcircuit the plug (on the cable). This will signal the ECU that the engine is hot. And then the diesel engine clatter should clearly calm down as the ECU corrects the injection timing from cold to hot running condition.
If this checks positive - then the blue sensor is defective (disrupted). its only some $15'ish from your dealer.

Richard Gallagher · Unread post by **Richard Gallagher** » 08 May 2006, 06:30

Take a look at the following link for info on how the relays are wired. Whilst its listed as for a Pug 306, Xantia fans are the same. www.peugeotlogic.com/workshop/base/workshop.htm
Then at the top of the screen click on electrical, then to the left, 306 cooling fans basic principal of operation.

rory_perrett · Unread post by **rory_perrett** » 08 May 2006, 07:45

Thanks one an all.

Nisk - disconnected batter for 5 mins, unfortunately didn't do the trick.

Richard - that's is a really useful link

Anders - I've got aircon, if I remember rightly there is a blue and and a brown connector obvious on the top of the thermostat housing . The brown is the biton (or some similar name). Will have a go at shorting out the blue on later.

rory_perrett · Unread post by **rory_perrett** » 08 May 2006, 10:38

Tried shorting across the blue plug, unfortunately no change/improvement.

Clogzz · Unread post by **Clogzz** » 08 May 2006, 12:50

If it gets hot, pull the wire off the brown sensor.
That will send whatever working fan to the high speed.
Stories here:

http://www.frenchcarforum.co.uk/forum/v ... hp?t=18871

http://www.frenchcarforum.co.uk/forum/v ... hp?t=18965

http://www.frenchcarforum.co.uk/forum/v ... hp?t=17012