So my cinq failed its emissions (1242 8v).. Results below.

Engine temperature 83.0°C

Fast Idle Test:
Engine Speed: 2450 – 2950 rpm - not checked
CO: max 0.300% 1.441 FAIL
HC: max 20ppm 60 PASS
Lambda: 0.97 – 1.03 0.979 PASS

Second Fast Idle Test:
Engine Speed: 2450 – 2950 rpm - not checked
CO: max 0.300% 2.515 FAIL
HC: max 20ppm 100 PASS
Lambda: 0.97 – 1.03 0.941 FAIL

Natural Idle Test:
Engine Speed: 750 - 950 rpm - not checked
CO: max 0.500% 0.404 PASS

Now, not really sure what to do about this other than give the car a good thrash on the way there. Oil & filter are good, air filter is clean, exhaust is ok. Car runs perfect. Thought i would turn down fuel pressure but then thought thats not gonna do anything is it on an injection car? I was thinking if i restrict the amount of air getting through the air filter would that result in ecu chucking in less fuel and thus bringing it down a tad.

Car has quite old petrol in it (with some injector cleaner in it), would that effect the emissions at all?

I just noticed that its down on the test sheet as 1108 not a 1242, would the limits be any different?

Got til Wednesday to sort it - chuck me some opinions.

edit: car has been sat for approx 3 years, i did do about 10 miles thrash on way to MOT.

I'd change the fuel then give a really good run out

How old is the oil?

I'd give it a really, really. good thrash, but change the plugs just before it goes in.

Mmm, i was afraid someone would say that.. has over half a tank in it lol. Is prob worth it though i guess

edit: its got fresh plugs and oil. I'm not sure how old the leads are, but they are uprated bosch ones and look to be a good condition - but completely unsure of age.

You reckon its worth swapping the lambda for a known good one?

You could always stick the old petrol in one of the many cars on your drive!

May as well change the lambda -- can't do any harm -- if it comes out!

ah have faith.. Will just steal the one out the seiT. They'll come out fine.

tbh, i always put high octane fuel in the seiT and the PGT so i don't want to stick it in them - isn't it true petrol loses an octane rating or 2 every year its sat in a tank? Or is that just an old wives tale? I know someone that'll take it though I have convinced my mate that he needs multiple cars like me so he always needs petrol now haha

you got any leaks from the system?

could be anything really, check exhuast leaks if any lambda then maybe cat, try some fuel treatment called forte.

They say all kinds of stuff about Petrol. Trouble is, it changes all the time, so none of the info is particularly reliable.

the exhaust is kinda cobbled together and is all welded. The guy let me under the car at the garage, neither of us could find any leaks at all - to change it would involve cutting and welding which i can't do, i'm 99% the exhaust is ok.

My mate is getting dressed now and bringing one his cars over to put petrol in. Shall i get some high octane stuff to go back in or just get the normal stuff?

High octane won't do any harm (probably won't do any good, either, but you never know!). Just a couple of gallons.

High lambda reading DOES NOT MEAN THE LAMBDA SENSOR IS FAULTY. Lambda is the AFR (with 1 being stoich) and for an MOT is measured at the tailpipe. All your lambda reading is telling you is that there is too much o2 at the tailpipe.

Changing the fuel can't hurt but I'd be checking the exhaust system again. Cover the tailpipe and check for leaks again. If it was poor fuel then I'd expect to see less of it burning, giving you more HC.

i know it passed HC but aren't they a bit high anyway?

edit: if stoich is 1... is under 1 lean or rich?

ok scratch that.. its rich as i thought.. so more air or less fuel or both.

Under 1 is rich. By the looks of it I would say that your lambda is not working at all, or knackered. What you should have done (not sure if that was an option) was to stop the engine, unplug the lambda sensor from the plug, restart the engine, let it warm up and see if it would be any different. This would at least give you some diagnostics.

On top of this I would say your CAT is not working at full capacity. And the fueling has only little to do with that, your CO to is excessive, I had similar figures with no CAT at all. With a healthy CAT you should have 10% of the max allowed.

In NL the max figures would be the same for 1.1 and 1.2 (and the same as you quote, this is actually EU wide I think).

Last option is that your engine was not hot enough (water temp. is kind of irrelevant) for the CAT to work at full capacity (not sure where yours is mounted, but by default it is very far from the engine), happened to me last MOT here in NL, the bastards were too lazy to wait for the fan to kick in at least three times, called me telling me emissions are excessive, when I arrived I asked them to keep the car idling for 15 minutes at least, and guess what, CO was down at almost 0 again

Well i have a known working lambda sensor and a gas analyzer so i can swap them about and see what difference it makes.. The car was properly upto temp, had been idling in there with the fan turning on and off for a while before he did the emission test. The CAT is stock in the original place, but i doubt thats it - most of my cars don't have a CAT and emissions has never been an issue (unless its actually damaged inside).

Was just after some pointers before i went to mess with the car, no point just swapping things at random i never had an issue with emissions before

blu73 said:

...The car was properly upto temp, had been idling in there with the fan turning on and off for a while before he did the emission test.

Click to expand...

That will have allowed the Cat to cool down though.
The ideal time for the emission test would have been straight after your 10-mile thrash.

ah right, i get ya.. well i have a 20 odd miles trip to the testers planned so i will give it some and ask him to do that first.

My bad, I've read it as a high lambda value. It's not, it's just rich - which ties in with high CO, fuel not burning properly. I don't think the exhaust is leaking anymore!

New fuel, and trash it :slayer:

right, just been siphoning petrol out of it, my face is on fire and mrs is shouting at me coz house stinks of petrol.. Had 15 litres in it. This mate is lending me a unused pipercross cone filter just for the MOT which should help a bit too.

Dont worry about putting too much fresh petrol in, ill be filling it up when i get my hands on it