MOT Emissions fail - CO

[jgra1]

hi all, my friends 206 1.1 petrol 1999ish - has failed on CO at idle and revs..

quick thoughts? Partially burnt fuel I am guessing.. plugs, AF .. I guess there could be a few other things that could cause it..?

thanks,
John

oops.. sorry thought I was puttting this in Peugeot!

[RichardW]

CO should be burnt by the cat, so either ECU is not going into closed mode or cat is goosed. Think you can check the cat with an IR thermometer if you've got one (should be much hotter out than in), otherwise Lexia check for coolant temp and state of O2 sensor in order. AF not a bad place to start if not changed recently. If it's driven gently, then some injector cleaner, good petrol, and a damn good thrash, getting it to the MOT station roasting hot might be enough to get it through!

[jgra1]

thanks Rich..

hmm... no lexia and none near me... will pick car up in a bit and see what's what..

[CitroJim]

Hi John My Daughter's 206 1.4 was always a battle to get through the MOT on CO and needed a new oxygen sensor and cat to do so. So be prepared for that...

Also, if you have a PP2000 handy, go through the procedure to re-initialise the engine ECU.

On the PP2000 also look at the signal from the oxygen sensor and check it's going up and down nicely between 100mV and 800mV or so

That's after doing all the usual service item of course...

My daughter's had one of those 'kitten' cats fitted and even then it was touch and go...

We sold it before it's next MOT but i believe to pass this year it needed yet another new cat In our time with the car it ate two oxygen sensors....

Seems they have an appetite for both

[citroenxm]

ALL I can say with a smile is B*l*o*o*d*y petrol engines!!

[CitroJim]

ALL I can say with a smile is B*l*o*o*d*y petrol engines!!

Says a man who loves his V6 petrol XMs....

They're not that bad Paul - a bit of a challenge at times but then so are diesels...

[citroenxm]

Well yes but i prefer my derv engine.. its just easyer to get petrol v6 xm.. well.. it was when i was looking...

[CitroJim]

To tell you the truth Paul, I much prefer petrol engines running on gas - nearly as cheap to run and MOT as a diesel then...

[citroenxm]

When i started using YOG on lpg gas was 48ppl.. ive watched the price rise in recent years.. a petrol engine is either gas or petrol.. a derv.. well its derv or veggie oil which if you find a friendly local chippy can cost you virtually nothing!! Lpg or petrol cant beat that.. can it??

[jgra1]

thanks for all that

well.. oil temp 80C

fast idle 2422rpm - 0.579 CO
Lamb 1.01
HC 115

second FI, 2427rpm - 0.642 CO
Lamb 1.008
HC 110

Nat idle - 855rpm - 0.519 CO

I must admit, when i started her this am I thought she smelt fuely.. like an old carby on choke..

[CitroJim]

HCs are a tadette high John too and that might suggest she's a bit rich but also if a cat is knacked/not working the car will smell fuelly. Non-cat cars now smell dreadful due to how today's petrol is formulated...

I'd be looking at the oxygen sensor I think. You don't need a PP to test it and as it's nice and accessible a good high-impedance voltmeter or oscilloscope connected between the grey and black wires will show what it's up to. A digital voltmeter, unless it has a quasi-analogue trending bar display, is not good but you should still be able to see if the oxygen sensor is doing it's thing and the ECU has gone into closed-loop...

Getting a PP2000 on it will take away a lot of guesswork though...

[Northern_Mike]

This may or may not help, but our 1.8 Mondeo MK1 that we had for 8 years and 144k miles used to fail it's MOT every year on emissions (my ex-wife used to take it while I was at work or it wouldn't have failed!.. read on). Each time, I would simply book it in for a retest, then run it up the M40 from J4 to J5 at high revs in 3rd and 4th gear, then hammer it back down through Stokenchurch to the testing centre in West Wycombe, where, with everything being really, really hot, lo and behold it would pass easily.

Had exactly the same with the 1.6 Focus I had last year. When I took it back, I got a "Christ, it smells hot" from the tester, but it passed on the emissions...

[jgra1]

thanks both.. being a 1.1 (and Chris750 will know) I drove it last night and today and it was driven 'well' ..

think the consensus is pointing at le chat.. no pp2000 Jim

[RichardW]

My guess would be the cat John - the lambda is about right, and HC low suggesting it's not running rich, so it would seem like the cat is not doing its job properly. A good hard run right down to the test centre might get it through....

[jgra1]

thanks Rich..

I have not been near a 1.1 for a while.. am I right thinking the cat is in front of engine, as against under car? should be an easy ish change?