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post #16 of 27 (permalink) Old 14th May 2007 Thread Starter
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Hi all. Just an update to my still 'smokey' Laguna.

I have been trying to sort this out for ages and still with no success. The lack of power was sorted, this was the turbo pressure sensor, only 30 quid from renault.

I have put a new EGR valve in. I had to remove the inlet manifold in order to drill the old EGR out as it was jammed in.

Car still smoked, I have since put a new Airmass, Turbo air pressure sensor, I have removed and checked the intercooler, have checked all the intercooler pipes, all ok. Checked wiring from airmass to all sensors, all ok. Camshaft timing has been checked and is aligned up perfectly. I have carried out a compression test and got 30-31 bar on all cylinders.

I have just about tried everything and the car still smokes, I have also put a new cat on it..

The car drives superbly, pulls excellently starts on the button and still it smokes... The smoke is black and not blue, the engine doesn't burn any oil at all and its had a new turbo a few months ago.

The only thing I haven't done are the injectors.. I have to get these reconditioned in order to eliminate them, then pressure regulator or this first, but then I don't know I would have gone through everything..

The only other thing is the ECU ???? could this be overfueling or could this have be remapped in any way????

Would I be able to get one from another car to test or would I need the keys for the ECU also????

I will get there in the end I'm determined to sort it out.. When I see other 1.9dci's on the road, they don't seem to put any smoke out..

If all fails, i'm gonna have to take the head off and take a look, although I have high compression, this proves my rings are ok, but does not give a full condition of the valves???

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post #17 of 27 (permalink) Old 21st May 2007
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Smokey heap of junk

Hi Merky,

Got the same problem with my dci , failed again today your info is invaluable, if you find anything else could you let me/us know, and i will do the same , my car is going into a diesel specialist on thurs so if anything comes up i will let you know,

Cheers, 1 ****ed off Laguna owner !!!!
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post #18 of 27 (permalink) Old 21st May 2007
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Hi Merky - as you say the smoke is black and that is a sign of over-fueling or not enough air - have you checked the fuel pressure sensor on the injector rail. The best way is to get the pressure going to the rail checked out before going for the injectors. The best injectors in the world won't work right if the fuel pressure is wrong. Most good diesel specialists can check the pressure. In my experience dodgy injectors tend to give out white smoke continously and black smoke is a pump or pressure or air supply problem.
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post #19 of 27 (permalink) Old 21st May 2007
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A lot of soot tends to accumulate in the back box of the dci engine. In non fap equipped cars it doesn't really get burnt off. Even a decent italian tune will not completley get rid of the soot.
Tap the underside of the exhuast system, not too hard but reasonably hard, this will help to dislodge the soot. Then take the car for a drive and floor it - you will see plenty of black smoke then, after a while it will almost disappear to normal "diesel smoke" when accelerated hard.

This worked on ours, it was getting a bit smoky, no other probs,drove perfectly. We do reasonable long journeys in it as well. Mentioned it to the garage ( Renault Independant specialist) at the 36k servcie, they did the above trick & appears to have worked.

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post #20 of 27 (permalink) Old 24th May 2007
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Black smoke and mot failure

Just had mine looked at by a diesel specialist, emisions down from 3.6 to 2.1, hooray, cause of fault was the turbo wastegate vacuum pipe had come adrift, not uncommon said the mechanic, so have a look !
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diesel , emissions , engine , failure , laguna , renault

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