Failed CO emissions on M.o.T.

[Abinthom]

Seat Ibiza 2003 5 door 1.2 litre. Amongst other things failed on CO emissions, but passed on Lambda. Requirement is less than 0.3%, mine at 0.636%. Garage (Kwik-fit) says needs new Cat, but is that really true, and yes, I know that is what K.F. are in the business of supplying. As all the other readings were within tolerance, could I do something else rather than fork out £140 + for new CAT?

[SammoVWT]

The cat has died early (ish), theres an underlying problem. What were your emissions readouts?

You can fit a new cat and pass it possibly, however if it is the CAT that has failed dont expect it to last long. The key ingredient is overfuelling, the question is why - they do have a set lifetime. Mine lasted over 95k miles, but that failed due to sensor fault which eventually gave out.

The only other thing you can do, short of a basic service is to get the car scanned - it may not show faults, but may show diagnostic information which is incorrect or out of spec.

A little bit of mind grease after that and im sure the solution can be found.

To put it into perspective, mine is a N/A 1.6L and a very old 8v, but my CO emissions were 0.01% on natural idle and 0.12% on fast idle, but I do have a small exhaust leak to take care of and the car wasnt fully up to temperature when that reading was taken.

[Abinthom]

The cat has died early (ish), theres an underlying problem. What were your emissions readouts?

You can fit a new cat and pass it possibly, however if it is the CAT that has failed dont expect it to last long. The key ingredient is overfuelling, the question is why - they do have a set lifetime. Mine lasted over 95k miles, but that failed due to sensor fault which eventually gave out.

The only other thing you can do, short of a basic service is to get the car scanned - it may not show faults, but may show diagnostic information which is incorrect or out of spec.

A little bit of mind grease after that and im sure the solution can be found.

To put it into perspective, mine is a N/A 1.6L and a very old 8v, but my CO emissions were 0.01% on natural idle and 0.12% on fast idle, but I do have a small exhaust leak to take care of and the car wasnt fully up to temperature when that reading was taken.

Thanks so much for your reply. The emissions report states:
Engine Oil Temp 80°
Fast Idle Test: CO = 0.652% HC = 14ppm Lambda = 1.011
Fast Idle Test: CO = 0.636 HC = 15 ppm Lambda = 1.023

Engine capacity = 1198 c.c. Mileage 127926 (yes, that's right, just shy of 128,000 miles!)

Hope this helps you to help me

Thanks so much again

[SammoVWT]

At that mileage it could just be from natural age, the lambda doesnt show any aging or exhaust leak, HC is low indicating a clean burn, so looks like they are right. CAT has just worn out - I would expect as much from that sort of mileage.


If you are paranoid about it, get the CAT replaced and then if you want you can still get it scanned and analyzed just to be sure

One thing to note, the engine temp is low, I would be expecting 90, but perhaps its different on these cars. Your CTS/thermostat may be broken or on the way out which can also give overfuelling as the car will be in warmup mode incorrectly (i.e. increased fuelling)

[zollaf]

i would first off make sure its all servced up properly, filters, plugs etc. scan it to make sure there are no codes, then go for an italan tune up. flat out like, hold the gears to the redline for as long as you can, then, whilst it is still baking hot, drive it into kf and get it re tested. if it still fails, it probably needs the cat.

[Doctle Odd]

They're usually scrap long before before that mileage, you're very lucky.