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Discussion Starter · #1 ·
i realise a lot has been said about smoking diesels already on this Forum, but does anybody have a definate answer.

my 2006 x-type 2.0d blows black smoke at about 1500rpm under load

i have fitted new ERG valve, cleaned manifold, replaced split intercooler hose & fitted new air & diesel filter problem is still there but not so bad.

any advice i would be greatfull.
 

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There's no definate answer as there's many reasons for a car to smoke.

I take it you are refering to black sooty smoke rather than blue oily smoke, if so you need to start looking at a possible air/fuel imbalance, though a puff of soot when initially accelerated is normal, when you accelerate it adds more fuel but it takes a moment (and needs the added fuel to speed the engine) for the turbo to spool up and get the air in, hence the puff.

If you're suffering heavy sooty smoke more often it's more than likely there's a fuel/air imbalance.

This could be down to a range of things.
The air is measured as it enters the intake by the MAF sensor and the ECU will fire the fuel in to match (match what it's programmed)

Blocked air intake or filter will starve the engine of air.

A fault with the MAF may give a wrong signal and too much fuel is added.

Air leaking off after the MAF, so it's leaking after it's been measured and not reaching the engine will give the appearance of over fuelling (which is in fact right fuelling, just short of air it was expecting) and soot.

Faulty EGR operation (just because it's new doesn't rule it out) can reduce the oxygen in the air that's induced, less air will give the same result as above.

Faulty or worn injectors can overfuel, too much fuel is fired in, there's not the air there to burn it completely, so it runs rich and sooty.

Faulty signal from the ECU, the ECU may just be firing in too much.
(I've a hunch the ECU is programed to allow for a little wear of injectors, say after firing X million times the ECU's programming will alter fuelling to accommodate this predicted wear, but the programming isn't quite right!)

A fault with when the fuel is fired in, to early or late and it won't get burnt properly. Cam and crank sensor issues.

Fuel pressure fault, high pressure fuel pump not producing the required pressure can alter the fuel/air mix.

Diesel Engine Smoke Explained - United Diesel, Shropshire
 
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I know I keep banging on about this BUT it may be worthwhile having your engine TerraCleaned to decoke it which will remove most of the carbon on the injectors and hopefully remove one expensive replacement option

I think Goudy covered off all the options tho - did you check the EGR hose hasn't split when you replaced the EGR?

Often it's the simple things which cause most problems so go for removing these first
 

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Discussion Starter · #4 ·
Thanks to both who replied, this is my first diesel so on a learning curb.

I have now replaced most of the items I think I can at home, including the large hose (which had a 1 inch split) that leads down to maf sensor from EGR valve which is also new.

I have noticed that the area around No2 injector is damp with diesel, can they leak, cause black smoke, and be repaired by DIY or i sit a specialist job.
 

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One or two of the unions on top of my injectors started to dribble a little also one of the unions on the fuel rail at the front.
Mop it all off with kitchen towel and nip them up with a spanner a little first then keep an eye on them, they have rattled loose or the seal in there may be shot.
Mine dried up after torquing them up a bit.

Mine also smoked a little from time to time, I don't think it was the dribbling injectors but the MAF sensor.
I fitted a Synergy 2 tuning box from here Synergy 2 from tuning-diesels.com
It has a MAF compensator, turn it off and it smokes a little more, turn it on and it's clear as a bell until it's really flogged.
The module it's self raises the fuel rail pressure, this is when I noticed the dribbling unions, though one did dribble before fitting.
 

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Discussion Starter · #6 ·
Thanks will have a look at tightning it up tomorow.

Not sure if its wishfull thinking but things seem to be improving with mileage after changing intercooler hose and filters on sunday !
 
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