MOT failurer on emissions, HELP!

[OrangeCorradoVR6 10]

Hello all, first post on here but here goes.

 

My Corrado failed its MOT today on a couple things, the one I am concerned about most and need help with is the emissions. It was on the emission hydrocarbon test where it required 0.3% to pass and it had a reading of 4.0, I ran a cleaner through and it only got it down to 3.8. What else can I do? It's a vr6 with a custom exhaust with a sports CAT recently added in as it's L reg. Only things I can think of is buying an original exhaust with CAT and changing the air filter (It's a K&N currently) or possibly getting it remapped. Oh and it only has 61000 miles on it so its not as if its a high mileage engine :/

 

Any ideas? :scratch:

[VAG-hag 0]

What make is the cat? Thats probably the source of your probs mate

[OrangeCorradoVR6 10]

It's a turborevs sports cat to fit the 2.5" custom piping (running a stainless tubular manifold too if that helps?)

[Kevin Bacon 5]

4% is very very rich. Lambda probe I reckon.

[OrangeCorradoVR6 10]

I had a new lambda probe fitted when the Cat was fitted last week :( The place where I bought the lambda has now changed the listing saying that the probe is for 2.0l vw/seat engines and below... Would that make a bit of a difference?

[Kevin Bacon 5]

The VR6 can be quite picky with lambdas. I've heard of a few not running right with ebay probes. How much are they from the stealers these days?

[Jon_vr6 1]

£160 odd quid last time i checked

[OrangeCorradoVR6 10]

I got the probe for £23.50 and yeah it was from ebay :D Where would you recommend I get one from for the VR6?

[VAG-hag 0]

Wanted ad on here?

[vw rule 19]

Hello OrangeCorrado,

 

yeah like the other guys have said it'll be your catalytic converter or the lambda sensor.

 

On the original cat the honey cone with in it will have small wholes,

so the exhaust fumes will pass through the honey cone at a slower rate.

Normally you have 10 to 15% reduced power due to the original cat.

 

Compared to the sports cat the fumes may well pass through at a much faster rate due to the larger honey cone,

in which case the exhaust fumes will have less time to be converted in to less harmful gases.

 

But like Kev has said I would replace your Lambda sensor first and go from there.

 

Have you scanned the ECU to see if it is holding a error code for a worn lambda sensor or air flow sensor ??

 

Your K&N air filter should be ok.

 

Have you put uprated cams in it or had any other mods done to it ??

 

Changing your engine oil and oil filter can reduce your emissions by 0.2 to 0.3%

 

 

Hope this helps

 

Si :thumbleft:

[OrangeCorradoVR6 10]

Nope the engines internals are completely unchanged, stock engine other than the exhaust and air filter, the oil and filter were changed only a coupe hundred miles or so ago, I will try and get the ECU scanned this weekend to see if it has picked up and fault codes, Yeah I think the lambda seems to be the best bet for now! :)

I'll have a look at the ad's on here for a lambda probe as soon as possible.

I'll post back when I get it re-MOT'D and say what I managed to get it reduced to, or if any other problems arise.

Thanks very much for the help! :D

[vw rule 19]

Hello mate,

 

if you can try to purchase a Bosch lambda sensor as these I believe are close to the original one,

I think new they are around £70.00 to £85.00

 

Something like this http://www.ebay.co.uk/itm/LS3829-Bosch-Lambda-Oxygen-Sensor-CAT-VW-Corrado-2-9-50-ABV-08-91-07-95-/181124437423?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2a2bdb95af

 

But from the main dealer they are a lot more.

 

Yeah or like you say unless someone on here has got a good new one ?

 

But yeah I would do a scan first of the ECU just to see what fault codes it is holding if any ?

 

 

Hope you get it all sorted out.

 

Si

 

---------- Post added at 11:16 PM ---------- Previous post was at 11:03 PM ----------

 

The only other thing regarding your K&N air filter.

 

Is it just a replacement filter in the original air filter box,

or is it a K&N cone filter which has replaced the original air filter box.

 

I'm just thinking of the breather hose / hoses ?

 

Because if you leave a breather hose off or some times a vacuum hose it can course the emissions to shoot up.

 

 

Si

[Roger Blassberg 0]

Is the blue temperature sensor faulty - could be overdoing mixture enrichment even when up to temperature. How's the idle and fuel consumption?

 

Best wishes

 

RB

[CorradoWannabe 1]

I had a similar issue on a previous MoT and a replacement lambda sensor from GSF did the trick

[Critical_Mass 10]

ive got a genuine second hand lambda FS if required. Ive never used it, got it as a spare off Fla from here. ;)

[OrangeCorradoVR6 10]

Thanks for all the replies, its a K&N cone filter so I'll check to see if any pipes have been left unconnected.

The idle is good and steady and the fuel consumption is average, not sure about the blue temperature sensor but it does tend to run cool then heat up very quick in traffic so I was wondering if a sensor could be faulty.

Also I had a look at the GSF one, seems to be good value will try and see if I can get a hold of a genuine one first :)

 

Critical_Mass would you be interested in selling the lambda probe? If so how much would you want for it?

[Critical_Mass 10]

Thanks for all the replies, its a K&N cone filter so I'll check to see if any pipes have been left unconnected.

The idle is good and steady and the fuel consumption is average, not sure about the blue temperature sensor but it does tend to run cool then heat up very quick in traffic so I was wondering if a sensor could be faulty.

Also I had a look at the GSF one, seems to be good value will try and see if I can get a hold of a genuine one first :)

 

Critical_Mass would you be interested in selling the lambda probe? If so how much would you want for it?

 

I would mate, ill dig it out.. not after much.. just need shot of it? £12 posted?

 

when i say ive never used it, i mean it is used, just not by myself. Was assured it was working.. and Fla is trustworthy.

 

Ill get you a pic :)

[OrangeCorradoVR6 10]

That would be great thanks! do you want me to send you a postal order or how do you want to be paid?

[Critical_Mass 10]

Paypal would be good mate, ill send you a pic tonight :)

[OrangeCorradoVR6 10]

Okay, cool :)

[Stonejag 10]

As an aside, make sure your cone filter is firmly mounted to something (I suggest the suspension turret, or some people use one of the three bolts holding on the aux belt tensioner). If the MAF and cone filter are left to flap around on the end of the inlet tube it cracks the inlet pipe and / or gives the MAF wiring metal fatigue, which makes it fall apart at the connector! Ask me how I know :D

 

Stone

[OrangeCorradoVR6 10]

Yeah I'll make sure it is! as I don't think it is properly mounted and you have got me worried! Thanks for the tip!

[renson 0]

I would say that the 0.3% Pass wasn't actually HC's as they are measured in PPM.

 

You are more than likely failing on CO. I don't run a cat and even at fast idle mine fails but only at 0.5%. I would get the garage to test your car on a standard test with live readings rather than in the MoT test.

 

This way you will get the CO. CO2, O2, HC's and Lambda all displayed. That way you will better see what the engine is doing.

[OrangeCorradoVR6 10]

Yeah the HC's are in PPM I just got mixed up between the hydrocarbon value and the carbon monoxide as it failed on both... Thanks for the advice, I got them to do a standard test and they gave me the print out, some of the results are:

------------------ Specification---Measured value

-Fast Idle CO (%) 0.00-0.30----3.89

-Fast Idle HC(PPM) 0-200--------384

-Lambda Reading 0.970-1.030---0.907

 

-Natural Idle CO 0.00-0.50------4.35

 

Basically it failed on everything... :scratch:

Edited May 18, 2013 by OrangeCorradoVR6

[Wesleyvr6 10]

Yeah the HC's are in PPM I just got mixed up between the hydrocarbon value and the carbon monoxide as it failed on both... Thanks for the advice, I got them to do a standard test and they gave me the print out, some of the results are:

------------------ Specification---Measured value

-Fast Idle CO (%) 0.00-0.30----3.89

-Fast Idle HC(PPM) 0-200--------384

-Lambda Reading 0.970-1.030---0.907

 

-Natural Idle CO 0.00-0.50------4.35

 

Basically it failed on everything... :scratch:

 

Thread revival! did you ever find the cause of this OrangeCorradoVr6?