Urgent Help Needed-mot Failure

[huwlj3]

My mk1 172 failed it's mot today. Just had a new cat fitted 12 months ago, so I don't think it's the cat. The car passed the emissions test at fast idle but failed on it's CO emissions while idle. Tolerance is up to 0.5 and mine was 5.06. Took the car to my mechanic and we tested the emissions again. CO was still 5.06, hc's were 665 and low lambda of 0.88.

Anyone experienced this? Can anyone help? Car is obviously running far too 'rich' while idle. Is it the cat? Lambda sensor? something else?

Help?

 

[edde]

SOuds like the lambeda worn as it should self correct at idle.

 

[huwlj3]

Cheers edde, how much for a new lambda? Is it best to get it through Renault?

 

[Mole]

you can buy universal ones for not very much, about £30 I think, just a case of cutting the wires on the original one, and attaching the new one to the wires so that you can use the original connector.

If its the same as the old mk1 clio then it'll be a 3 wire lambda sensor, 2 wires being the heater element inside the lambda sensor and 1 for the signal

 

[huwlj3]

Had a new lambda today and the CO level has dropped to 2.8, still way over the tolerance level of 0.5 allowed at normal idle for the mot. HC's dropped as well from 600 odd to 300. So it's not the lambda. Renault seem to think it might have had the ecu tampered with (chipped)?

 

[roland]

Re: Urgent Help Needed-mot Failure - Same here any resolve?

Did you get to the bottom of this. Mines done the same thing and now the garage reckon it could be the VVC actuator putting the valve timing out a bit.

Has the 172 got 2 lambdas like the 182? They removed and cleaned one and it dropped (from 6 as well as taking it for a thrash with some additive dropped it 1 or 2 as well) to 3 or so.

Its getting expensive now on the diagnostics labour charge ! ahh

 

[edde]

Re: Urgent Help Needed-mot Failure - Same here any resolve?

Did you get to the bottom of this. Mines done the same thing and now the garage reckon it could be the VVC actuator putting the valve timing out a bit.

Has the 172 got 2 lambdas like the 182? They removed and cleaned one and it dropped (from 6 as well as taking it for a thrash with some additive dropped it 1 or 2 as well) to 3 or so.

Its getting expensive now on the diagnostics labour charge ! ahh

Yep the 172 does often have two some phase 1 172's only have one though.

Usually a good hard driver and injector cleaner fixes them all.

 

[dk]

i have a 182 that failed its MOT due to CO too, see here

http://www.cliosport.net/forum/showthread.php?t=206332&highlight=failed+mot

renault are looking at it on saturday.