Excessive Carbon Monoxide Emissions

[abelw44]

Evening all,

 

So I took the heap of blue German shite that is my A4 Avant b5 for an MoT over the weekend, which it failed miserably on emissions. 

 

 

 

So, my limited understanding of Chemistry, leads me to believe that the production of Carbon Monoxide is the result of incomplete combustion - and therefore either the engine is not getting enough air, or its getting far too much fuel.

So, I took the air filter out, and although not perfect it was restricting air in any way, and I stripped the ducting back as far as I could - no debris to be found here either.

So I think it can't be to do with air.

Saying that, however, when I read the fault codes on it, one of them was "insufficient air flow on air mass flow meter" or something along those lines. But surely insufficient air would make the car dump less fuel into the engine? 

 

If it is too much fuel being supplied, I'm struggling to think what might cause this - faulty injectors? Fuel pump? 

 

If anyone can shine any light on this, it would be much appreciated!

 

Cheers,

abelw44

[sierraman]

I'd try getting it absolutely warmed through then retry it.

[abelw44]

I'd try getting it absolutely warmed through then retry it.

 

That does seem to be the consensus elsewhere too!

In fairness, it had done nothing more than idle on my driveway before it went for the MoT....

 

Thank you, I shall give it a try!

[wuvvum]

You might get away with a thorough warming through - the second fast idle test wasn't too far above the limit.  My C4 blew a 0.45 and the tester reckoned an Italian tune-up to get the cat up to full efficiency before taking it in for the retest should do it.  Your natural idle figure looks rather high though.

[sierraman]

Either that or the time old trick of using something else for the purpose of passing the emissions.

[fordperv]

I'd try getting it absolutely warmed through then retry it.

This with an Italian tune up

[dollywobbler]

Yup, a good Italian tune up. Make sure the engine really is up to temperature too. Our Nippa struggled a couple of years ago, because the coolant sender was slightly duff, so it was over-richening the mixture slightly - just enough to cause a high reading.

[twosmoke300]

A just fail like that is either a knackered cat or cat not up to temp . As suggested above - take it back when stinking hot for a try if not it’s cat time .

Don’t get a euroflo one - they don’t even pass an mot when new

[tommotech]

To make a proper assessment you’d need to see the oxygen and carbon dioxide values on a four gas analyser. Also crankcase breather issues can cause issues with emissions testing, as said above try the Italian tune-up first.

[Junkman]

Buy something 40 years old or older and be done with that stupid nonsense once and for all.

[twosmoke300]

You cannot honestly believe that the world would be a better place with no emission controls at all ?

[Junkman]

It used to be. Then came 1986.

[MarvinsMom]

we get this every, EVERY year with the mini MPI.

 

if the emissions on it are tested last (as is usually the case) then they will be way off.

 

if the emissions are tested first, as soon as the car arrives at the test station, or, if the car has been for a blast along the bypass, then the emissions will be well within the permitted limits.

 

we find that as the car is sat on the ramps idling away to itself then the engine will be upto tempreture, while the cat is getting cold.

 

and a cold cat leads to squiffy emissions.

 

so, take the Aldi out and rag the arse off of it, get it hot, and then re-test it.

 

garanteed* to work.....

[twosmoke300]

Aren’t those mini mpis in a loophole for emissions testing ? Can’t they be done as a non cat test or something daft

[MarvinsMom]

no, we were running the car without the cat on it for a couple of years, whicch was MUCH better cos it ment that the exhaust was in 2 pieces (front pipe and then back box) while with the cat fitted its in 3 bits (front pipe, cat and then the back box) 

 

we find that the exhaust been in loads of bits means that it all hangs lower than it would otherwise do (its only supported off of the gearbox, and on 2 rubber mounts right at the back after the muffler) and that it catches on speed humps and the like. like last year when we went of a pleasent drice through Dalby Forest only to find that the Mini had beached itsself on the stupid friggin' speed hump at the "visitors centre" 

 

at least it was mid-week and there wasnt anyone else around.....

 

but i'm rambling. 

 

anyway, 2, maybe 3 years ago, VOSA or what ever they are called started to really tighten up on emmission testing, and we had to put the cat back on.

 

so the Mini is subject to all the emission limits applicable for a car built in 1997.

[scaryoldcortina]

Aren’t those mini mpis in a loophole for emissions testing ? Can’t they be done as a non cat test or something daft

yeah, more or less.

[New POD]

You cannot honestly believe that the world would be a better place with no emission controls at all ?

 

Bring back Lead in Petrol and 2 strokes with a bit too much 2 stroke oil in the petrol. It never did me any harm.

[danthecapriman]

Buy something 40 years old or older and be done with that stupid nonsense once and for all.

Amen brother!

Not long to go now either.

[danthecapriman]

Bring back Lead in Petrol and 2 strokes with a bit too much 2 stroke oil in the petrol. It never did me any harm.

Yes! Now that’s the kind of thinking we need.

And while we’re at it bring back fuck off huge cars with big fuck off V8’s and no cat’s.

[forddeliveryboy]

You cannot honestly believe that the world would be a better place with no emission controls at all ?

 

That's a very interesting question, if by emission control you mean the gubbins bolted to a modern car to allow it to pass government targets. Governments are more interested in raising revenues than preventing lung disease any more than can be gotten away with.

 

There is an argument which says all we've done with emission control is sweep the problem under the carpet by picking off the low-hanging fruit, to create a far worse situation and allow us to continue to smoke around burning hydrocarbons at an extortionate rate without having to come up with a solution.

[Junkman]

Did someone say smoking?

 

Do away with that stupid smoking ban as well, while I'm at it.

[Guest]

Looking at those figures, it's overfuelling at idle, which has contaminated the cat. Lambda is OK on fast idle so it's clearing itself on throttle. Is the thermostat OK? Does the car get up to 80 odd degrees, and if so I'd be looking at the coolant temp sensor. Get it on a diagnostic and make sure the ECU is seeing the temp is correct and not just taking a flatline reading. IIRC the gauge has a different sensor on these. Get that sorted then give it a good hard run to try and clear the Cat, hopefully it can burn off.

 

Oh, and make sure the MOT man actually takes the oil temp, and doesn't just stick the probe in his coffee.. Ahem.

[Guest]

The idle limit for the spi Mini was 0.75% CO. Some testers may not check this..

[chatsharris]

Bottle of Cataclean and an italian tune up got me another year out of the Civic. Recommend.

[Junkman]

We conclude:

 

Emission controlled cars that are ever so just about jiggery-pokeried through an annual test,

but at all other times emit a metric shitload, make this world a better place.

[wuvvum]

You might get away with a thorough warming through - the second fast idle test wasn't too far above the limit.  My C4 blew a 0.45 and the tester reckoned an Italian tune-up to get the cat up to full efficiency before taking it in for the retest should do it.  Your natural idle figure looks rather high though.

It didn't work . Got down to 0.38 but wouldnae go any lower. So near yet so far.

[martc]

VAG product and a high emission reading? Quelle surprise as they would say at Renault. Were the monkeys lying?

[abelw44]

Evening all,

 

First of all, thanks to everyone who replied!

 

I decided that before I just ragged the tits of the poor thing, I'd run a fault code scan again, and see what I could learn.

Having done so, I've discovered that the Intake Manifold Valve is Open Circuit. My limited understanding and what I could find from a Google trawl tell me that this controls a valve that decides whether air goes in the intake or elsewhere. Assuming thus us correct, could the valve potentially be stuck in the wrong position and therefore not supplying enough air to the engine?

 

 

Also, would the broken O2 sensor skew the car's readings and make it think it's running lean? Because if there's one thing it isn't...

 

Thanks,

abelw44

[Stanky]

Can you clear all of those, then take it for another run? Some could be ancient and suggesting issues which are no longer present?

[abelw44]

VAG product and a high emission reading? Quelle surprise as they would say at Renault. Were the monkeys lying?

 

Ooooooff! Right in the feels...

 

 

Can you clear all of those, then take it for another run? Some could be ancient and suggesting issues which are no longer present?

 

I went out today and cleared the codes, before starting it up again and they all came back - 'fraid I'm too much of a wimp to take it for a run with no MoT or Tax...