Cat and emissions

[Prudie]

My car has failed its MOT on emissions (very high reading). The garage didn't have time to diagnose or fix so I paid for the full MOT and don't know what to do next. General opinion is it could be the catalytic converter and/or lambda sensor but should I get those replaced with no guarantee they're faulty or splash out for a diagnostics test first? It's all very expensive and very depressing. There's no engine warning light on (in case someone asks me). Can anyone advise?

[boxtops]

Prudie I'm sorry about your car, but I honestly thought this thread was about pongy cats...... ;-)
Can you get a second opinion from another garage? I am only full of relief that mine passed its MOT on Monday. It seems a costly way replace equipment if you're not sure that's what it is

[Prudie]

Hi boxy I didn't see your answer sneak in there! I did wonder about the title - could have put it in A&N and it would have meant something quite different!!
Thanks for the sympathy anyway, it has really thrown me as I expected it to pass and I am now without a car (and I'm very fond of it too)

[gingejbee]

Surely you should confirm what's causing the problem first- cats and sensors are very expensive.

[SlackAlice]

What car is it and how old?
Any fault with the lambda sensor normally causes the engine management light to come on. Sounds like a faulty catalytic converter but would recommend a diagnostics test first.

[Prudie]

It's a Celica and it is quite old (M reg) but has only done about 60K. It looks like I will have to fork out for a diagnostic test but on top of that I think I only have 10 days to get it fixed and re-tested before I have to pay the full price again.

[Andyvon]

I think you'll have to fork out for a diagnostic test from another garage Prudie. The MoT garage really should have helped you more. It may be the cat if it hasn't been changed for a long time but don't assume it is as they are several hundred pounds. IT may well be something straightforward.

When you get the check done make sure you hold on to the printout as that has all the error codes and faults from your car's ECU. If necessary you can show that to another garage and not have to pay for another test.

Good luck.

[Prudie]

Thanks Andy (and everyone else) I will get the diagnostic done. I think the fact that the garage said they were too busy to help further only added fuel to my mood because it's a small local garage that I've gone to for the last 5 years out of loyalty. They've never failed it before.

[AlBags]

Post the printout readings Prudie! Especially CO .. HC's and C02.

Important we can see what is high exactly.
Different high readings imply different causes.

[Prudie]

Ok they're in the car and it's too cold to go and get them. If I post them tmrw after work will you answer? From memory he said 5.5 when something should have been 1.2 (or something)

[AlBags]

OK.
I'll take a look when back tomorrow evening. Probably CO then.
Make sure you post car year/CC too. : )
Al.

[Andyvon]

That does sound like CO. We'll be watching tomorrow Prudie, although I think AIBags probably knows more than me - I think he's in the industry.

[Prudie]

Eddie the car did a long fast run on Saturday and is worth way more to me than £250 or so for a new Cat. It's black and sleek and drives superbly!
The figures for fast idle test actual values are:
RPM 2497
CO 5.251
HC 240
Lambda 0.849

It passd the natural idle test

[Prudie]

98 2000cc

[AlBags]

Hi Prudie ..
In late again. More old cottage revamping underway.
Right then.
Looks like parked rich with a lambda not running.
This is likely to be either the MAF Sensor in the intake pipe (lump next to air filter) or the lambda sensor (O2 sensor) in the exhaust downpipe.

I would check/clean the MAF sensor first .. as there is some history of problems with this car.
http://www.toyotaceli...index.php/t10124.html

O2 sensor info here ..
http://www.toyotaowne...x.php?showtopic=31069

Ask local car bod to carefully remove MAF and check/clean .. delicate job as it's a filament.
You 'could' replace O2 sensor as a matter of course .. some here ..but you will need part number from a Toyota dealer (using your VIN)
http://cgi.ebay.co.uk...0a0aad5821522fe5f7eea

I'll wait to hear back!

[AlBags]

The HC are not really high enough to indicate a mechanical problem .. piston ring .. etc. This figure will fall when lambda comes right (good combustion ratio .. which is a lambda of 1.0)

[AlBags]

... and for what it's worth .. I don't think it's the cat.
You could buy a cat anyway for much less than quoted. I would find a breaker tho, as a donor.

[Prudie]

Albags that is a lot of useful info (that I don't understand) but I will ingest it and pass on. Thanks for the help and I will let you know.
x

[AlBags]

GL.
I have fixed things like this before a few times .. It was always one of these components.
A decent guy will check the MAF for you .. maybe even test the lambda out with a voltmeter. I think it will be stuck rich tho .. and that could be a failing in itself .. or the MAF reading.
There are other causes .. but unlikely ones.

[Prudie]

Just in case anyone actually was interested I was thrilled to get my MOT today. Got a new Cat for £140 but have been told that they don't know if it will sort the problem for next year as thought it was the ECU telling something the car was cold when it wasn't. Whatever I now have some months to think of my next move.