Advice on NCT failure

masit

Hi all

I have a 2007 K12 1.2 petrol Nissan Micra. It is my mother's car and has been sitting for about 1 year. I'd start it every now and again and drive it up and down my lane just to keep it moving. When my mother had it, there would always be an engine warning light on but I have a cheap OBD reader and I could get rid of the light and it would pass the NCT test. The test has been out a while because of it sitting so I decided to try and NCT it the other night but it failed on emissions and the light was back on after it came out from the test. Code is P420. I could hear the tester revving the crap out of it so I had a bad feeling

Results are.

Engine/Oil Temperature 92.C

Low idle Co 0.32vol%. Above 0.30% MAJOR

(990 rpm) HC 75ppm. Above 0ppm. N/A

High idle Lambda 1.01. Not between 0.97 & 1.03 PASS

(2,740) Co 0.41vol%. Above 0.20% MAJOR

HC 38ppm. Above 200ppm PASS

After the test I turned off the light again and got some dipetane and drove at high revs for a few miles and then went for a normal drive for about 60kms. Doing 100kph in this yoke, the revs are still high. At about 40kms the light came back on.

In the results it's showing the lambda passed so I'm thinking my self it's a catalytic converter. I just want peoples thoughts on anything else before I go down the converter route.

Thanks in advance

Oops!

The CO is just barely over, is there a slight leak in the exhaust somewhere?

Luna84

https://www.boards.ie/discussion/comment/121583621#Comment_121583621

The high rev test is well over though.

Oops!

Ya that's true, i just looked at the idle CO, bit more investigating needs to be done alright.

teediddlyeye

https://www.boards.ie/discussion/comment/121583621#Comment_121583621

Exhaust leak would give high lambda.

Looks like cat OP

masit

Thanks for your replies. I had a 2.0 S-Max before and brought it for a test and the tester was revving the **** out of it. Failed on emissions too. Tester said he revved it as much as he could to try and get the reading down, so when I heard the Mirca been revved this I was thinking the worst. When I brought the S-Max to get it fixed, the mechanic showed me the old CAT, there was nothing in there , could see straight through it. I think I'll go and get the CAT replaced. Shouldn't be a biggish job, if the old bolts play ball. Its right there at the lower front of the engine.

Luna84

https://www.boards.ie/discussion/comment/121584589#Comment_121584589

You would be better off going to an exhaust place, well unless your mechanic welds. As an exhaust specialist welds everyday so is more inclined to do a better job.

masit

Update on NCT

So I changed the catalytic converter and rebooked an NCT. Passed with flying colours . The internals of the old cat was completely gone. Thanks for the comments.