NCT smoke fail

Under His Eye

The auld lads diesel jeep was in for the test and failed the smoke test. Reading was 6 instead of the allowed 3.


Is there anyway to get this down easily?

Rows Grower

Under His Eye wrote: »

The auld lads diesel jeep was in for the test and failed the smoke test. Reading was 6 instead of the allowed 3.


Is there anyway to get this down easily?

You can get a product made by Wurth, I think it's called Dieselcure.

Add it to the fuel tank a couple of hundred km's before the retest and again about 50km before the retest and it should help.

I'm sure someone else will have more knowledge of exact way to use it for best results.

derra_121

Under His Eye wrote: »

The auld lads diesel jeep was in for the test and failed the smoke test. Reading was 6 instead of the allowed 3.


Is there anyway to get this down easily?

Rev the absolute ****e out of it and drive for approx 30 min constant (motorway or so) to get the engine up to temperature directly before you drive to the centre.

Hotter your diesel engine the better the chance of passing.

Littlehorny

Put a fiver's worth of petrol with twenty quids worth of diesel into an old Peugeot that had failed before, drove the stones out of it and it passed on the re-exam.

Del2005

Get the thing fixed properly and stop pumping noxious fumes into the atmosphere.

Rows Grower

Del2005 wrote: »

Get the thing fixed properly and stop pumping noxious fumes into the atmosphere.

You must have very little to worry about that you take the time to chastise someone looking for advice.

mgbgt1978

Basically much the same advice as already given. Try dipetane, a fivers worth of petrol with around €50 of diesel ( not much less). Drive it along a decent road for about 4/5 miles at around 60/70 mph in 3rd gear just prior to the test.
Above everything else do not let it idle outside the NCT Centre for more than a 30 seconds or so when you get there.

StereoSound

Del2005 wrote: »

Get the thing fixed properly and stop pumping noxious fumes into the atmosphere.

Everyone loves a cheap or free solution before paying a fortune.

I say rev the shoite out of it until kingdom come, then put it through again when the engine is hotter then the fires of hell in damnation!

Del2005

Rows Grower wrote: »

You must have very little to worry about that you take the time to chastise someone looking for advice.

I worry about people sticking plasters over major issues. If a car is putting out too much smoke then it's faulty and needs to be fixed. But people will try everything possible then to fix it.

There's a reason why we have limits on the noxious emissions.

George Dalton

In the vast majority of cases where an older (pre-DPF) diesel fails on emissions there is actually nothing wrong with the car. A lot of people’s driving style means the engine never reaches high revs or sustained peak load under normal driving. This means there is a certain amount of soot sitting in the exhaust. Then the vehicle goes for NCT/CVRT and the engine is revved to the limiter and all the crap comes out of the exhaust and causes a fail. A good Italian tuneup is all that is required to ensure a pass.

mgbgt1978

....and many well-meaning NCT Receptionists will often tell Diesel Owners to let the Engine run while waiting to be tested "to make sure it's warm".
Probably the worst thing you can do just before the Smoke Test.

pablo128

mgbgt1978 wrote: »

....and many well-meaning NCT Receptionists will often tell Diesel Owners to let the Engine run while waiting to be tested "to make sure it's warm".
Probably the worst thing you can do just before the Smoke Test.

I have never gotten that in over 10 years continuously driving diesels. In fact they tell you not to leave the keys in the car while waiting to be tested.

mgbgt1978

I have..... twice.

Rows Grower

pablo128 wrote: »

I have never gotten that in over 10 years continuously driving diesels. In fact they tell you not to leave the keys in the car while waiting to be tested.

Now that you mention it, I often had to go back out and get the keys for the receptionist.

demanufactured

OP,
To get the smoke opacity down, a good run prior to the test should help.

You havnt stated what make and model of jeep it is.
I'm assuming it's an older vehicle?

If a good run doesn't sort it, I'd be speaking with a diesel mechanic before using any additives.

It's could be down to a faulty fuel pump or bad injectors.

pablo128

demanufactured wrote: »

OP,
To get the smoke opacity down, a good run prior to the test should help.

You havnt stated what make and model of jeep it is.
I'm assuming it's an older vehicle?

If a good run doesn't sort it, I'd be speaking with a diesel mechanic before using any additives.

It's could be down to a faulty fuel pump or bad injectors.

Or simply burning lots of oil too.

Basically roast the engine before bringing it for the test. If it still fails on smoke, get it looked at. But I'd spend nothing first. I wouldn't even put in an additive as it can mask an issue.

Macdarack

Rev the stones out of it the day before the test. It's that simple.

Under His Eye

It is an 05 Hyundai Santa Fe. 120K km on the clock. It has never given him bother till now. Not burning oil at all.

The auld chap is a very sedate driver so getting him to red line it could be interesting.

Macdarack

Under His Eye wrote: »

It is an 05 Hyundai Santa Fe. 120K km on the clock. It has never given him bother till now. Not burning oil at all.

The auld chap is a very sedate driver so getting him to red line it could be interesting.

Sedate driving is the cause of this issue, carbon/sut build up in the exhaust, when the tester revs the stones out of it the carbon gets blown out and it fails.
Grab a hold of the yoke and rev her up, no need for any snake oil diesel treatments.

demanufactured

Under His Eye wrote: »

It is an 05 Hyundai Santa Fe. 120K km on the clock. It has never given him bother till now. Not burning oil at all.

The auld chap is a very sedate driver so getting him to red line it could be interesting.

There's part of the issue then.
It needs to be given a good burst of high revs every now and again.

Doctors room ghost

Redline the fcuker and give her a spin with plenty of punishment.up through the gears plenty of revs.knock out the old cobwebs.then a good dose of dipethene or the stp treatment bottles and test it hot.leave her ticking over before it goes in the door

Dartz

Del2005 wrote: »

Get the thing fixed properly and stop pumping noxious fumes into the atmosphere.

A good shoieing is a proper fix if it's only smoking because it's bone cold, or has filled itself with carbon from dozens of cold runs.





Now if you'll excuse me, I've got some icecaps to melt.

doolox

I rarely put my bus above 2,000 rpm and delight in getting from A to B with apparently little effort in comparison to the many small petrols which I revved the sh"""t of to get moving at all. That is my problem. I have NCT on next saturday so I will be revving the absolute sh££"455t6te out of the car before that test......

pablo128

doolox wrote: »

I rarely put my bus above 2,000 rpm and delight in getting from A to B with apparently little effort in comparison to the many small petrols which I revved the sh"""t of to get moving at all. That is my problem. I have NCT on next saturday so I will be revving the absolute sh££"455t6te out of the car before that test......

Absolutely. It will do it no harm at all.

Pkiernan

The night before the test, leave it in neutral with the engine running and a block on the accelerator pedal.

Hopefully this will blow your engine.

zilog_jones

Under His Eye wrote: »

It is an 05 Hyundai Santa Fe. 120K km on the clock. It has never given him bother till now. Not burning oil at all.

The auld chap is a very sedate driver so getting him to red line it could be interesting.

My only concern before driving it hard would be if the timing belt is in good shape, if it has one. If it's overdue due to age or mileage I wouldn't risk it. I'm not familiar with these engines though.

CJhaughey

zilog_jones wrote: »

My only concern before driving it hard would be if the timing belt is in good shape, if it has one. If it's overdue due to age or mileage I wouldn't risk it. I'm not familiar with these engines though.

They have been known to lose timing, fortunately they have finger rockers that should break before there is too much damage done.

Under His Eye

Passed. No problems. Thanks for the helpful advice.

Neilw

Under His Eye wrote: »

Passed. No problems. Thanks for the helpful advice.

What did you do to get it to pass?

Mine is failing too, I think the test result was 8.something.

lawred2

Rows Grower wrote: »

You must have very little to worry about that you take the time to chastise someone looking for advice.

To be fair, fixing the actual problem is great advice

Under His Eye

Italian tune up worked for me. Floored it for the last few days and drove all the gunk out of it. Result went from 6.0 to 1.1.

joywalker

My sons 161 fiesta has failed its NCT and 3 subsequent retests after on emissions… he has spent a fortune on it ( literally) . Even an new ECU, if it fails again .. any suggestions apart from pushing it off a cliff 😭

https://www.boards.ie/discussion/comment/119437003#Comment_119437003

You'll need to provide more information than that. What are the results? What fixes were attempted? No one is going to respond to such a vague opener ..

mikeecho

Petrol/ diesel ? (I presume diesel)

Mileage?

What were the results of the 1st, 2nd 3rd tests.?

What was done after each test?

Did any of the "fix's" improve the situation any bit?