Nct Fail - High Emissions

munzab

Hi everyone wondering on your views regarding this.

Have an 03 1.8 fwd rav4. Went thru nct today and passed all comfortably except for the emissions.

This was the reading:

Engine oil/oil temperature 83 degrees C

Low idle (750rpm) CO 0.04%. HC 25ppm. Fail would be above 0.3% and hc 0ppm. This was a PASS

High idle (2840rpm) CO 0.34%. HC 70ppm. Fail would be above 0.2% and hc 200ppm. this was a FAIL


Lambda on high was 0.99 (0.97-1.03). Only written down besides the high idle value.



Anybody any ideas what might be wrong? Car just had a full service 10 days ago. Last year the car passed the nct at 0.17%, i didnt even look at the value.


We had been thinking of selling the car soon and wondering what would that mean in terms of selling. Retest is 28 due for another few weeks but we are due to leave the country in 10 days and will miss the deadline for retest last day, so need to get it fixed soon and retested, but not really too keen in investingntoo much in the car at this stage.

Thanks for the suggestions

sumo12

Full tank of fuel, add some dipetane and do some motorway driving in 4th gear. 9 times out of 10 will clean emissions enough to pass test. Bottle of dipetane will cost no more than €20

jimgoose

I suppose the air-filter is in order, given the car was recently serviced? There are a few sensor problems that can cause this - MAF, TPS, coolant temp, or even the oxygen sensor. It would be useful to get the OBD codes read, if any.

Chimaera

Lambda is normal, HC and CO are a little high. I doubt there are any sensors gone south here.

Has it been serviced recently? I'd think new plugs and air filter would get you pretty close to a pass here. And be sure to take it for a good hard run before the test: the "Italian Tuneup". Do a few full acceleration runs from ~60-120 km/h in third on the motorway once it's up to normal operating temperature (once you're not getting in anyone's way). This will help dislodge any crap and warm the engine properly before the test.

rcanpolat

for every NCT i go to the local petrol station and grab 2 bottles of that engine cleaner stuff. throw it into a half full tank and drive it for 10 minutes booting it and making sure to slam on the brakes several times to slosh it around in the petrol tank (no idea if that does anything but sure meh) during the nct i always see the guys checking my emissions about 2 or 3 times because they keep getting odd readings but it always passes in the end

munzab

thanks a lot for the info guys.

mechanic asked me to put in fuel additive, and half a tank and to drive around. he'll check it afterwards to see.

can i ask, should i put in the additive (i belive its diphetane?) before or after i put in the half tank of petrol?

Chimaera

You'll mix the additive into the fuel more quickly if you put it in before adding fuel.

munzab

just an update

new cat installed, passed nct at 0.07% high idle.

happy enough.