Toyota Yaris 06 NCT fail high emissions

DarrenRob

Hello, my girlfriend's car is a toyota yaris 06. The first NCT gave the following results,

Low Idle (780rpm)
CO 0.26 vol% *Fail is above 0.30%*
HC 133 ppm * Fail is above 0ppm*

High idle (2680rpm)
CO 2.29 vol% * Fail is: not between 0.97 & 1.03
HC 639ppm *Fail is above 200 ppm.

After this test the catalic converter was replaced for a brand new one as recommended by a mechanic.

The retest gave the following:
The fail rates apply as above.

Low Idle (1,010rpm)
CO 2.57 vol%
HC 1,238ppm

High idle (1,010rpm)
CO 2.57%
HC 1238ppm

The reason the results above are the same as the NCT was abandoned due to excessive smoke.

The test became much worse than the first time even after replacing the catalic converter which apparently on changing had holes in it.

Thanks for reading I look forward to some advice!

porsche boy

I would doubt the catalytic converter was the issue here. The excessive HC is what needs to be resolved. That is hydrocarbon, basically unburned fuel. If I get a chance later I will analyse the emissions and let you know what's going on

rex-x

What was the lambda reading? you are missing that

If it was your mechanic that diagnosed the problem and changed the cat I suggest that you change a mechanic as he frankly doesn't have a clue. With the initial results there is no chance in ell the cat is the cause. It might have failed due to whatever is wrong with the rest of the system but with those readings the main issue needs to be fixed first.

Now you'll need start from the scratch and very likely in the end you'll need another new cat. But only after the overfuelling has been properly diagnosed and fixed. Whatever you do don't let anybody near the cat until the high idle emissions are down to CO <1.0 and HC <100 with lamdba of 1.000(000).

PS. You didn't supply the high idle lambda value but most likely it way off, like 0.90. You need to get the injection system to produce a solid 1.00 lambda, otherwise you'll just waste money. The most important value of the high idle readings is that 1.00.