Hi guys,

Took her in for an mot and failed on lambda reading was excessive and c02 emmisons excessive...

Can I fit a second hand cat or re-condition?

What lambda sensor do I require it's a 1.2 16v auto no other advisories

Any help great fully recieved

do you got 2 lambdas? how you know cat is dead

There are other similar threads recently.

The lambda reading at MOT test is a calculation by the machine based on the gas analysis. It is not a test of your oxygen sensors or your cat, so don't rush out to replace anything until the actual problem is determined. Ideally we need to see the gas readings printout to help. Scan it and post it here.

Two recent similar issues have been:
1. An air leak into the exhaust giving an excessive oxygen reading at the tailpipe.
2. An air leak in the test machine hose, causing a fail for several customers.

portland_bill said:

There are other similar threads recently.

The lambda reading at MOT test is a calculation by the machine based on the gas analysis. It is not a test of your oxygen sensors or your cat, so don't rush out to replace anything until the actual problem is determined. Ideally we need to see the gas readings printout to help. Scan it and post it here.

Two recent similar issues have been:
1. An air leak into the exhaust giving an excessive oxygen reading at the tailpipe.
2. An air leak in the test machine hose, causing a fail for several customers.

Click to expand...

Thanks for the reply I've attached the emmisons test, (ignore the engine mount I have a new one waiting to be fitted) I just hope it's an easy fix

Thats alot of carbon monoxide been produced

Cgeck things like airfilter been clean

It's doing well on the test just crappy CO
Which may be the cat im affraid

Any fault codes?


Ziggy

Next step would be to read the fault codes. Better still, attach MultiECUScan and read the oxygen sensor readings. A duff primary sensor could be the culprit.

I would expect an engine management light on.
If the primary sensor is not working properly it should show the light.
If it is working ok, but the cat is dead, the secondary sensor should report this and pop up the light.
Blocked air filter may cause rich running, as might a dribbling injector, but the oxy sensors should be picking this up and the ECU desperately trying to correct it.

I guess you're in Nottingham, but if you confirm this, there may be someone nearby with MES who can help.

I have no lights on at all which is making me question it I have no loss of fuel consumption and still runs brilliantly it came as a big shock!

I have been looking at second hand cats but I don't want to change that if its not the issue

Being a girl driver I have no clue

2nd hand cat could be as bad as the one you have, trouble is a cheap new cat will likely be duff by next year so look for a type approved one. The Lambda reading is quite low - a high reading would be caused by an air leak as mentioned above - and is probably caused by it running rich. Not a solution I normally recommend but it may work out cheaper to let the garage sort it - you could easily spend £££££s and not get anywhere.

Further to the above we went in to the engine and realised only one lambda was plugged in so we've plugged in the second which could explain low lambda reading (previous owner) on looking at the cat it's virtually brand new I did have a exhaust leak a few months back but was fixed. im tempted to have it plugged in to see if any fault codes appear due to no EML being on

Also any links to cats would be appreciated

put some of this in the tank, http://www.eurocarparts.com/ecp/p/c...additives/fuel-treatment/?542770410&0&cc5_169


and then let the car blow some cobwebs off on a quiet stretch of motorway.


send it back in for a retest..with a warm engine,


if the lambda sensor as been unplugged, iwouidnt condemn the cat just yet.

I wouldnt give it to them warm

I'd send it in red hot - the fan kicking in and out regulary

Which is alot easier with the temperatures now going over 10C

If 1 sensor is unplugged, it'll mess the fueling up
A code read and live data trace will help loads!

Ziggy

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Nottingham22 said:

Further to the above we went in to the engine and realised only one lambda was plugged in so we've plugged in the second which could explain low lambda reading (previous owner) on looking at the cat it's virtually brand new I did have a exhaust leak a few months back but was fixed. im tempted to have it plugged in to see if any fault codes appear due to no EML being on

Click to expand...

Which one was unplugged, top or bottom?

Believe it was the bottom one unplugged she's going to my friend today to be looked at I was thinking of a cat additive I will keep you updated thanks everyone for the help

It may well be OK now - If the ECU doesn't know what's coming out of the cat it usually defaults to a mid range fueling setting.

I'm gaining 40mpg around to work (dual carriageway and normal roads) motorway 50mpg I put £15 in every 2 weeks