Failed NCT Smoke Test - BMW 320D (E46)

friendface

Hey,

I've just had my E46 320D fail the NCT smoke test. Reading was 3.900/m with a limit of 2.500/m. After a hoard of other problems recently, I'm fairly skint at the minute. I'm just wondering would this be an easy DIY fix or would it need to be taken down the garage to be looked at.

I've read other people just putting a small amount of petrol in the tank and then revving the car up to help clean out any sooty residue. I don't want to cause more problems with the car though. The guy at the NCT said it may be a matter of cleaning out the injectors.

I'm pretty good when it comes to any DIY jobs on the car and wouldn't mind attempting any work myself. However, I need to have this done by next Saturday to avail of a cheaper re-test.

Would really appreciate any advice if anyone else has had this issue. Thanks

muckeyw

How are you I'm around naas and work for a BMW garage id check your egr valve and clean that out first and go from there could also be a problem with injectors to or vacuum.I'm hear to help anyway

barneygumble99

the limit should have been 3.000 for a turbo diesel car anyway. 2.5 is for non turbo's

voxpop

Throw in some injector cleaner for a diesel and give it a good run - reving it to near the red. Then when going to the test, drive enthusiastically.

I wouldnt put petrol or parafin in a modern diesel - fine in the old diesels.

richardsheil

Dipetane is good. I have had good results with it in similar circumstances.

irelandspurs

richardsheil wrote: »

Dipetane is good. I have had good results with it in similar circumstances.

This get dipetane

friendface

Thanks for the replies everyone. Just to let ye know, I got Dipetane and mixed half a bottle of the stuff with a full tank of Diesel, then took her out the M6 and drove near the red-line for about 20 miles

Had the NCT last Saturday and passed with plenty room to spare. Had a reading of around 1.200 this time around, down almost 70% in the space of a week. So I can definitely recommend Dipetane and a bit of enthusiastic driving.

challengemaster

What year E46?

I know you got it through with the dipetane but that doesn't mean there might not be a problem.

friendface

challengemaster wrote: »

What year E46?

I know you got it through with the dipetane but that doesn't mean there might not be a problem.

It's a 2001. I do a lot of city driving, short stop-start journeys of under 3-4 miles. I'm guessing that's what caused a build-up in the first place. The car does get a run down the motorway every 4 weeks or so but I don't generally drive it very hard anyway.

Is there a common problem on certain e46's which may have led to this?

challengemaster

There can be a lot of turbo issues, from pipes wearing over time and forming holes leading to some power loss, turbos failing, or even worse, swirl flaps being ingested by the engine - basically goodbye car.

If the turbo was banjaxed there'd be a lot of smoke and very little power above 2k rpm

friendface

challengemaster wrote: »

There can be a lot of turbo issues, from pipes wearing over time and forming holes leading to some power loss, turbos failing, or even worse, swirl flaps being ingested by the engine - basically goodbye car.

If the turbo was banjaxed there'd be a lot of smoke and very little power above 2k rpm

Don't think she's losing power. Noticed a slight dip in power for less than a second while accelerating once a few months ago but haven't noticed any problems since. I know the 2003-> 150bhp model had a common turbo problem with the swirl flaps being ingested as you mentioned.

When I took it out on the motorway last week I drove it in 4th gear on the motorway around 3-4k rpm and it was very responsive. I wouldn't ever drive anywhere near that range normally though. Can't say I've noticed any other issues so fingers crossed I won't encounter any of the problems you mentioned. In fairness, the engine itself has been no trouble since I bought the car, can't say the same for brakes/suspension/bushings though.

challengemaster

Yeah, those are the other feckers

Hopefully tis nothing serious anyway