Nct revving the bajasus out of car on emissions test

Chris Dowling

Just brought my car for re-test failed 3little things 1being emissions by .02% anyway mechanic sorted everything serviced new cat , now at re-test my car was rev to hell for good 3-4mins while car that came on ramp beside it a minute later was left idling for test and moved on to the next stage before mine, then the bad end that car passed mine failed only on emissions again??????

Is this normal/ right?

Nissan doctor

There would be no issue with revving a healthy engine but also no need to to carry out the test....unless your car wasn't fully up to temperature. How far was your drive to the test center?

Is the car petrol or diesel?

Voodoomelon

Can make little difference sometimes how long it takes to drive there, I was waiting a solid hour once I got there. I'm sure the lads look at the temperature before revving though.

George Dalton

The tester was probably trying their best to get your car to pass the emissions test. You should be grateful to them for making an effort to get it to pass rather than just sticking it on the machine and printing out the fail sheet.

Chris Dowling

Ok went back out test was this morning asked to get rechecked explained why and said other cars seemed treated differently so guy put it on emissions thingy and guess what came back perfect !!! Weird or what

But now I'm happy

dr.fuzzenstein

Wonder if it's possible to restrict maximum revs for the engine just for the test, i.e. have a "testmode" for the engine that revs out at 3k rpm and fuel management system would emphasise on emissions?
Could be an app for a smartphone that could connect to the ECU, select "NCT mode" for the test and select "Smoke screen mode" afterwards.

pred racer

dr.fuzzenstein wrote: »

Wonder if it's possible to restrict maximum revs for the engine just for the test, i.e. have a "testmode" for the engine that revs out at 3k rpm and fuel management system would emphasise on emissions?
Could be an app for a smartphone that could connect to the ECU, select "NCT mode" for the test and select "Smoke screen mode" afterwards.

Afaik a diesel has to be able to rev to a certain percentage of its manufactured spec to stop chancers like you:D
(i could be 100% wrong though;) )

Nissan doctor wrote: »

There would be no issue with revving a healthy engine but also no need to to carry out the test....unless your car wasn't fully up to temperature. How far was your drive to the test center?

Is the car petrol or diesel?

Just curious here, but surely revving the nuts off an engine with no load isn't good for it? Nothing to back up this claim it just feels wrong

fasttalkerchat

dr.fuzzenstein wrote: »

Wonder if it's possible to restrict maximum revs for the engine just for the test, i.e. have a "testmode" for the engine that revs out at 3k rpm and fuel management system would emphasise on emissions?
Could be an app for a smartphone that could connect to the ECU, select "NCT mode" for the test and select "Smoke screen mode" afterwards.

I've heard of people throwing a bit of oil or kero into the tank to get through.

mitchaul

fasttalkerchat wrote: »

I've heard of people throwing a bit of oil or kero into the tank to get through.

How does that work?

leeroybrown

fasttalkerchat wrote: »

I've heard of people throwing a bit of oil or kero into the tank to get through.

mitchaul wrote: »

How does that work?

Kero (paraffin) or other additive fuels with a higher burn temperature cause the extra emissions from the engine to be burned. It should also clean the injectors, etc. It's a good quick fix to get your car through a borderline test fail but it doesn't solve the problem and if you do it more than occasionally it can be bad for the engine.

Modern diesels with DPFs may not like it either.

Del2005

dr.fuzzenstein wrote: »

Wonder if it's possible to restrict maximum revs for the engine just for the test, i.e. have a "testmode" for the engine that revs out at 3k rpm and fuel management system would emphasise on emissions?
Could be an app for a smartphone that could connect to the ECU, select "NCT mode" for the test and select "Smoke screen mode" afterwards.

IIRC you sign away your engine when doing a diesel NCT. They need to rev it and there's a chance it could blow, if it blows then it failed

pred racer wrote: »

Just curious here, but surely revving the nuts off an engine with no load isn't good for it? Nothing to back up this claim it just feels wrong

Unless it's full revs and/or they are doing it for ages then a good engine won't be affected. If there's something wrong with your engine it'll do it harm.

Leonard Hofstadter

Revving an engine like that won't do it any harm once it's warmed up, has been properly maintained (serviced at the appropriate intervals all through its life) and is in good mechanical health.

In fact, giving a fully warmed up engine plenty of revs and taking them on a spirited drive is good for them now and again to clear out any builds up of carbon deposits etc.

dr.fuzzenstein

fasttalkerchat wrote: »

I've heard of people throwing a bit of oil or kero into the tank to get through.

My car actually broke down just before the NCT with an electric fault.
After fixing the fault the mechanic threw some hydraulic oil into the tank and it passed the smoke test with some very low emissions.
Need to find out exactly what he did, excessive revving was no problem for my car in any case, I heard him rev it once or twice, the guy seemed gentle enough with it, definitely not revving the nuts of it.

pred racer

captainspeed wrote: »

In fact, giving a fully warmed up engine plenty of revs and taking them on a spirited drive is good for them now and again to clear out any builds up of carbon deposits etc.

Dont worry, my car gets this, alot:D

fasttalkerchat

If anyone is trying the kerosene trick just make sure you don't get dipped on the way to the NCT centre! Its illegal.

Nissan doctor

pred racer wrote: »

Afaik a diesel has to be able to rev to a certain percentage of its manufactured spec to stop chancers like you:D
(i could be 100% wrong though;) )



Just curious here, but surely revving the nuts off an engine with no load isn't good for it? Nothing to back up this claim it just feels wrong

Revving at stand still puts much less strain on the engine components then when under load(driving). Once its fully up to operating temperature of course.

Many diagnostic test procedures are done at higher revs and believe it or not, on some older Fiats, revving from idle to the limiter 3 times resets the engine warning light once a fault has been repaired!:eek:

Senna

fasttalkerchat wrote: »

If anyone is trying the kerosene trick just make sure you don't get dipped on the way to the NCT centre! Its illegal.

I used to put €5 of petrol in diesel cars (older cars) before doing the test. I have no idea if it made any difference but none of them failed on emissions so continued doing it.

bmstuff

Revving the engine continuously, over a long period of time, like I see regularly being done by some of those immature NCT testers, is not good, period.
Especially on big engines, some of them really like to rev them up. Even in the car park, before the car starts being tested...

The engine needs a good air flow to run properly, while parked, this is not the optimal condition for the engine to run.

mickdw

Chris Dowling wrote: »

Ok went back out test was this morning asked to get rechecked explained why and said other cars seemed treated differently so guy put it on emissions thingy and guess what came back perfect !!! Weird or what

But now I'm happy

So you are saying you turned up without appointment in the afternoon having failed in the morning and the guys took your car in because you were not happy with how they tested the car earlier?

Nissan doctor

Nissan doctor wrote: »

Revving at stand still puts much less strain on the engine components then when under load(driving). Once its fully up to operating temperature of course.

Many diagnostic test procedures are done at higher revs and believe it or not, on some older Fiats, revving from idle to the limiter 3 times resets the engine warning light once a fault has been repaired!:eek:

That's a very fitting fault code reset method from people who invented Italian tune up.