Emissions Advice

nesthead

My 03 Micra failed NCT today on low idle and lambda reads. Print out from NCT lads says:

Low Idle: CO 0.01% vol - pass
(1,160rpm)
HC 20 ppm - fail

High Idle: Lambda: 1.03 - fail
(2, 680 rpm)
CO 0.01 vol% - pass

HC 29 ppm - pass


It's over revving, so would that be the cause of the Lambda fail and the HC fail on low idle?

Don't understand any of this stuff and I'm freaked cos my mechanic thought it was burning oil and needed a lot of engine work (to the tune of 1,200 euro!!!) before the NCT was done.

Any help would be much appreciated!!!

Plug

OK lets look at it.
You don't need a cat thats fine.
Now it is running a wee bit rich, so you could be looking at an air flow sensor or an 02 sensor. Scrapyard job.
What mileage is on it?

nesthead

39k, nothing really.

what do you mean scrapyard job?!!? like send my car to it? :eek:

Plug

Nooooo:D
Just to get maybe an 02 sensor or an air flow sensor. just ask your mechanic what it needs.

nesthead

Oh good. I like the car :rolleyes: Do you know if it's expensive to have that stuff done?

Plug

Depends where you get it done. It will have to be put on a diagnostic computer I'd say. Its not going to be overly expensive but it won't be too cheap either.

nesthead

Thanks! Will get it checked out on Monday!

crosshair1

The fact that the low idle is too high is one part of the fail,
the high lambda at high idle test is the system running lean (too much air or not enough fuel)

Could be an intake air leak causing the high idle, any hissing noises?
On this car this can be due to incorrectly fitted throttle body housing when
replacing the spark plugs.

I would not make sure no parts are fitted until the cause of the idle problem is identified.

nesthead

No hissing noises. Bit of a rattle though...