Black Sooty Smoke

1996 2.1td 150K

Well it smokes, black sooty smoke when under load or booting it. It scraped through the emmisions because I accidently left the air filter at home ;-)

Anyway according to my feeble brain black smoke is caused by too much fuel or too little air. So with a brand new air filter it must be the fuel.

Mr Haynes tells me that its all singing and dancing ECU controled fuel injection so dont fiddle with using spanners, hammers etc

It all points to the injectors. Question is, before I spend £120 ish at GSF do you all agree with my diagnosis?

TIA

Mark

Mark,

I'm no diesel expert (my 2.5TD is my first diesel car) bu tyour diagnosis sounds about right. The colour of the smoke tells you a lot about the problem. Black, brown and white all point to separate dignoses. There are a few websites that cover this in detail. I'm at work at the moment so I don't have acces to the URL's but a quick search for 'diesel' and 'smoke' on google yields thousands of hits. There are even some dedicated forums on the subject.

However, before going spending lots of dosh on new injectors consider the possibility of refurbishing them. I used a local diesel indy who relaced just the nozzles (the part which wears) and tested them all in my presence for £19 each. His name is Gordon and the company name is Paragon Diesels in Denny, Scotland. Tel 01324 825523. He may even consider doing them by post if you can afford the downtime.

A separate diagnosis put the blame for my 'melted' piston nightmare on a faulty injector producing the wrong spray pattern and/or the wrong fuel injection rate compared with the other three cylinders. The moral being - don't underestimate the importance of properly working injectors. I'd hate to have paid a garage for all the work I did to repair the faulty piston.

Cheers

Norrie

Black smoke sometimes isn't black smoke, its soot that has accumulated in the exhaust system over a period of gentle driving. If you give it a good thrash at high revs on the way to the MOT you will likely find that it doesn't smoke when you get there.

Peter.N.

Cheers PeterN

As Ive just dropped down from a 2.5 to a 2.1 Ive been thrashing it anyway just to try and get somewhere near the performance.

Ive had this car for about 40K / 3 years although it was laid up for one of those years and its always been a bit on the sooty side. However, as the roads round this way beg for XMs to fly Ive not experianced gentle driving for a good many years.

Ive phoned the local derv specialists and he seems to think it may be the injectors but could not say for sure. Strangly enough it was a weird conversation

ME: Could black soot be duff injectors?
HIM: Could be what sort of car do you have?
ME: A Citroen XM 2.1td
HIM: Bloody Hell! do you now
ME: Yes I do
HIM: Mmmm
ME: Good cars but not many on the road now
HIM: I bloody know that Ive got one

Nearly a hour phone call ensued

A fellow green blood! drives 1990 2.1td left hooker, no toys, 150K and only now had its first major fault - losing water thru the head. His second car 1.7td BX (like I used to have)

Im going to see him soon but feel I may need to set aside a few hours nattering time.

Cheers

mark

Well finally got around to taking it in.

As its the all singing all dancing epic electronic system they could rig it for a fault code reading.

The problem (so they / laptop) says

Faulty needle lift injector - This has been giving duff info to the ECU, which in turn has sent duff info to the pump and overfuelling the chambers. Results lots and lots of unburnt derv and the performance of a tractor, but without the torque.

New needle lift injector £86 plus Vat Citroen only. Add to that the recon of the remaining injectors plus the code reading and its been an expensive excercise.

Needle lift injector on order, not off the shelf of course, but should only be a day or so.

They also said that the epic pumps do give up the ghost at high miles.. so thats something nice to look forward to.

TTFN

Mark

black smoke could be just low compression

Well, had it back for nearly a week now and all I can say is

Why the hell didnt I have them done earlier!!!

It would now give my 2.5 a run for its money, goes like brown smelly stuff off a large scooping spade.

Black smoke only when foot hard to floor but this blows out and is then gone - Confirms Peter Ns comments.

Slight "fog" in following car lights at night but cleaner than any derv Ive ever had.

All Im left to do now is
Speed sensor
Clutch cable
Drop links
Binding brake
rear window
non locking boot

and then Im done................................

Mark