Failed NCT smoke emissions

polc07

X-trail 2.2 dci failed for smoke emissions at 9.999 , so i went to motor factors and they told me to use dipetane and drive hard on lower gears with high revs for a bit , NCT told me reason it failed is that it's only used for short runs , that Diesels need regular long runs , Hope this Dipetane works and brings down reading for wed , anyone have other idea's ???:)

Ronnie Beck

Put the diptane in and take it to for a very long motorway spin accelerating to the speed limit in 4 gear. Your EGR and intake are blocked from sitting at low revs. Exhaust gases are recirculated through your intake to reduce emmisions...google it;) This is one of the reasons why diesels are recomended for longer journeys.

If your anyway handy you could clean it out by hand. (Easier on some engines than others)

Edit: Replace your air filter too. Your cylinders aren't getting enough air to burn all the diesel which results in smoke.

sheehan12

i know some people put a 1/2 litre of petrol in to help with the smoke test. that with about 40 litre of diesel too

polc07

Ronnie Beck wrote: »

Put the diptane in and take it to for a very long motorway spin accelerating to the speed limit in 4 gear. Your EGR and intake are blocked from sitting at low revs. Exhaust gases are recirculated through your intake to reduce emmisions...google it;) This is one of the reasons why diesels are recomended for longer journeys.

If your anyway handy you could clean it out by hand. (Easier on some engines than others)

Edit: Replace your air filter too. Your cylinders aren't getting enough air to burn all the diesel which results in smoke.

Thanks Ronnie

I had it serviced before NCT air filter etc were changed I saw them been changed , how would u clean out by hand ?? ,

Ronnie Beck

polc07 wrote: »

Thanks Ronnie

I had it serviced before NCT air filter etc were changed I saw them been changed , how would u clean out by hand ?? ,

Not sure on your engine, but you normally just remove it (3/4 bolts) soak it overnight in diesel and clean it out in a bucket with oven cleaner. Its nasty stuff. You don't want to get it on anything you don't mind throwing out. Search the net for info. like this - http://raindefence.hubpages.com/hub/How-to-remove-clean-or-bypass-an-egr-valve-from-a-trafic-vivaro-primastar-diesel-van. That pic at the top is probably close to yours.

pic of intake here -
http://www.npoc.co.uk/forum/nissan-primera-p12-dci-egr-blanking-help-needed_topic50732.html

polc07

Thanks Ronnie , useful info

nct tester

no guarantee it will pass by using dipetaine, driving hard, cleaning out egr etc, 9.9999 is the highest reading that the machines give so the likelihood is that the actual smoke reading is higher. either get it checked in an indy garage after carrying out any recommended remedies or else book it in for retest well before the 30 days are up in case it fails again. or just get someone to stand behind it and give it a few hard revs and if the black smoke is still visible , there is something else wrong.

Ronnie Beck

polc07 wrote: »

Thanks Ronnie , useful info

Sorry i don't know one end of a nissan from the other. Maybe someone else on here will point you in the right direction.

@ nct tester. It's hard to know which is the best option there, depends on the individual situation I suppose. Agree it is very high but maybe the op just drives around a town like a nun(no offence). Would blocked injectors ,from running at low pressures all the time, together with badly caked up EGR/Intake not result in that reading?

nct tester

yeah it possibly would, im just saying there's no guarantee though when the reading is that high.

brinty

Had similar problem last week and failed NCT on it.

My wife had the car around town for a few days in advance as i work in dublin so she needed use of my car. I usually do 500-600mile a week and put something in the oil tank last night recommended by Halfords, so gonna drive her hard this evening down the motorway and hopefully clear the **** out of her.

I was also checking emissions when driving this week and doesn't seem to bad re smoke from exhaust, i'll check when i get her home. hopefully she gets through as I'm looking at trading too.

polc07

Ronnie Beck wrote: »

Sorry i don't know one end of a nissan from the other. Maybe someone else on here will point you in the right direction.

@ nct tester. It's hard to know which is the best option there, depends on the individual situation I suppose. Agree it is very high but maybe the op just drives around a town like a nun(no offence). Would blocked injectors ,from running at low pressures all the time, together with badly caked up EGR/Intake not result in that reading?

Hi All,

Just a quick update , X-trail passed at 2.450 on emissions ( below 3.0 to pass ) , thanks for all replys , Dipetane and a driving it hardish done the trick , safe for another 2 years

nct tester

delighted it was a cheap enough fix in the end.

polc07

Cheers NCT tester