Zx Diesel - Smoking

[joss]

My ZX 1.9D is producing increasing amounts of thick black smoke and reducing power under load.

This happened a couple of months ago, to the point where it would not run at all, this was diagnosed as a blocked cat, which I had replaced with one from GSF. The car had been standing for two years before I got it so some buildup of soot was not that surprising.

 

Afterwards the car ran brilliantly with no smoke - for a while. Surely it can't be the same thing again. It is not as bad (yet) - could it be there is a buildup of soot elsewhere in the system? Should I have changed the backbox too (it had been one of the most recent new parts on the car when I got it so I thought it would be ok)?

 

Any ideas?

[techbod]

that's a difficult one because many things can cause that but most common would be injection timing which is electronically controlled

 

Black Smoke

This is due to a air to fuel ratio imbalance, either the fuel system is delivering too much fuel into the engine or there is not enough clean air (oxygen ) a few things to look for :

 

Faulty injectors (injectors need attention at about 100.000 to 120 000 miles)

Faulty injector pump

Dirty air cleaner

Turbocharger or intercooler faulty

Problems within cylinder head, valves clogged up due to faulty EGR (exhaust gas recycling unit)

[joss]

Thanks for the reply, maybe we can eliminate some things:

 

the car is a 97 model if that makes any difference - non-turbo

mileage - car has done less than 60k

injectors - I have tried a dose of injector cleaner, made no difference

I have changed air filter, old one looked ok too, also did fuel filter

fuel consumption is higher than I would have expected

engine sounds like it is running ok (to my diesel-ignorant ears)

starting is ok, in fact less smoke when cold (this points to a cumulative air problem?)

 

TIA

[techbod]

cumulative air problem or blocked EGR valve/ pipes,

 

im not into the diesels so I can only point to known problems ;)