Catalytic converter failed after 18 months?

AdrianC

jimmylad007 wrote: »

But the fact that the garage want to straight away go and replace the fairly new cat without first investigating other possible causes ie. faulty sensors / dirty filters that are cheaper fixes just makes me wonder if they're trying to rip me off.

Anyway, look at the actual emission figures.

Lambda - pass. So the oxygen sensor is almost certainly fine, since it's running the right mixture.
HC - pass. So there's not excess unburnt fuel, unlikely to be a filthy air filter or running too cold "on choke". Taking that and the lambda together, that pretty much rules out air leaks anywhere.
CO - fail. One job of the cat is to oxidise CO to CO2.

Both sets of fast idle figures, consistent.

Those readings shout "dead cat", especially when a quick glance shows that it's got a cheapie fitted.

jimmylad007

Ok guys, thanks for all your help. I'll go with the new cat then. Just wanted to make sure first of all there wasn't something else obvious that I was missing.

I'll see what their opinion is on the old cat once it's off - whether it's just a cheapy or whatever.

colino

With infrared, laser thermometers now being so cheap, it's easy to check if a cat is working or not. While cheapo cats can fail quickly, better to check it before expensive parts chuckery.

Paul_the_Painter

Take it for Italian tune up on the way to the garage for the new cat. Get them to retest it before fitting new cat. (If required)

mrmot

I'd spend £20 on a bottle of Cataclean and get the cat nice and hot. I've seen it take CO readings down from 0.8% to 0.2%.

JustinR1979

Some take a LOT to get through, a thrash beforehand and straight on the tester.
I've noticed recently they do emissions halfway through, years ago I used to put them on first.
I don't know if they have to do test in order these days, or are just stupid.

colino

Wouldn't call the NTs stupid, but the guidelines are so basic as to take away any thought (allegedly!) from the job. There's even a recommended path of inspecting underneath the car, just in case you only check one corner and forget the rest.

Limey

My Celica failed on CO emissions this year, I suggested a new cat to the garage and they laughed and said they rarely recommend cat changes. I was told to take the car for a drive. High revs, low throttle input for 20 mins and come back for a retest.

Passed with flying colours.