318iS Emissions

[Dave_M3]

things never seem to go my way these days.

Failed the NCT today on emission as well as a few other stupid things like a damaged iS lip, which the tester proceeded to knock off breaking all but two clips when going onto the brake testing machine.
But that's another days work...

It failed on emission for Hydro-carbons, Showed 1000 and something.
750 is the maximum value permissible?

Anybody able to shoot a few things that I could check?
Suppose the first is to make sure the AFM is right and that it's not running too rich and maybe putting new plugs in again.

Worst part is that a month ago when I checked it the emssions were way under the threshold. The tester reving the sh!te out of my poor little M42 while testing it didn't help either

[neilofla]

Aye, the limit for NCT is 750 parts per million hydrocarbons for cars registered before 1993 I think

Right enough its supposed to be revved to 2500 for a few seconds, then tested at idle, the tester shouldn't have been revving it too hard.

I have my NCT in a couple months, I have a sneaky suspicion I'll have a problem with HC because there's a right whiff of petrol from my exhaust at all times.

I'm thinking replace coolant temp sensor, and check AFM?
Mine doesn't have O2 sensor or cat, but does yours? O2 sensor could be a problem

[Dave_M3]

No, no Cat or anything.

Chipped and re-mapped, heater plate removed and those kinda things, also Inlet Cam advanced 6 degrees alright.

But tha shouldn't matter, last time it was tested was on a right cold morning and it was only around .2 CO2 and 500 HC ppm, could have been less even since I can't really remember.

Coolant sensor should be ok since the car holds a perfect temp and warms up nice and quick.

More than likelt is my AFM or plugs I think. There is a nice wiff of petrol off it alright and only gets around 25-26mpg since christmas. Very strange the HC doubled in just one month though
Has to be due to him reving it up, when it's on cam at 7100rpm, I'm sure the HC wouldn't be too good, lol

[neilofla]

Mine gets 26 - 28 mpg, doesn't look good for my NCT....

HC doubling is strange. I wonder what MOT results are for hydrocarbons, anyone?

Dave, look at the parts for sale, I think I saw someone offering an AFM at a good price in case u want to swap it out

[neilofla]

20 nicker for AFM

http://www.e30zone.net/modules.php?name ... ic&t=98438

(us fenians have to look out for each other u know...)

[Dave_M3]

Ya, I was actually looking at that thread the other day , didn't think it was the AFM I would be needing though

I'll probably just swap it with the one in my track car first to see if it will make a difference, then if it does I'll pick one up

[kevin316i]

Got HC = 275ppm at my last NCT for my iS. Limit is 750ppm on the sheet. After I imported the car from the UK (with a full MOT...) I found out it had a major emissions issue and the fault turned out to be a misfitted intake manifold gasket, so you should give your car a good check to verify there are no vacuum leaks.

[pacerpete]

High hydrocarbons equates to poor combustion. Usual causes are intake air leaks/incorrect timing/ bent or burnt valves . A good running engine , even a sad old IS should not have any more than 200 ppms. If it has , there are issues

[Dave_M3]

Hmmm, I must check what it actually got the first time round, I might have got it mixed up.

1048 is just a joke altogether though...

I don't like the idea of bent valves
Leaking gaskets or vacum hoses are likely alright since I'm planning on changing them soon. Suppose bringing back the inlet cam for the test might be a good idea too...

[Weeman]

I've just smashed the cat of my euro one, Dutch MOT (APK) is in a few weeks, its fingers crossed time, as i too have an old school petrol smell, friendly tester and an extra ten euros should suffice LOL

[Dave_M3]

Ahhh, The first time I put it throught the test it was showing 242 ppm HC.
Now 1048
Some increase!!!

My Lecturer in college was telling me best thing to do is mess around with the AFM after putting in new plugs and any vaccum pipes in that might need replacing.

He reckons, it shouldn't be anything serious internally since the car is running ok...

[monkey]

have you compression tested it as it sounds like you may have a valve gone .

[Dave_M3]

It did take a very long time to fire last Sunday, but think that was a lazy fuel pump...

If it was a valve gone, it would be running like a bag of nails though, wouldn't it???

[tomtomtom]

leaky pipes? i had just this trouble with my iS and it was perished pipes and throttle body gasket

[Dave_M3]

First I'll swap over the AFM and put new plugs in and see what difference it makes at a mates garage where he can test it for nasties.
Then I think I'll change all the manifold gaskets now and pipes.
Paint up the rocker cover and plenum nice and shiny then

Failing that, I'll just drop in another M42, lol.
A strong spare will be handy anyway