Mazada 6 08- burning oil - fails emissions

djsim101

Hi All,
I would love your expert opinions on this. Car failed NCT last Friday on the emissions test. The car has been consuming oil for the last while. I was fully expecting this tbh. From my reading the results, they are a bit outside the limits

here are results:
Low Idle CO 1.46 col% HC 567 ppm above 0.3% fail, above 0 ppm fail
High Idle Lambda: 0.81 CO 6.02vol% HC 997ppm, not between 0.97 and 1.03 fail, above 0.20% fail, above 200ppm fail

Is there anything I can do to try and get this car passed on the re-take, or am I wasting my time. Unfortunately, I am not in a position to purchase a replacement car, at the same time, no point in pumping money into the car as well :-(

Thanks for your help

mullingar

They are very high results but I note your Lambda is only 0.81. A reading that low indicates a problem with the air filter blocked, o2 sensors faulty, faulty MAF or a dead cat.

I'd start with a decent service and a quick emissions check by any half decent independent mechanic before you attempt a re-test

Hopefully that will fix the lambda which should hopefully sort out the high HC values too, my only other concern is that engine is known to burn oil and the only fix is new rings & stem seals.

Toyotafanboi

I definitely wouldn't waste any money on a service unless the car is chronically overdue, it's unlikely to do much to help.

Get the car to an intelligent mechanic to assess (not fix) the lambda issue and make a judgement call from there.

If the lambda issue is a reasonably priced fix I'd proceed with it and then do another emissions test.

If the lambda issue is looking like an expensive fix, then it's too much of a financial risk with that car IMO. Unfortunately those engines are prone to burning excessive amounts of engine oil so even with the lambda value sorted it may still be failing on HC, which would require an engine rebuild or replacement to cure.

mullingar

To add,

The lambda reading is a measure of the amount of oxygen present for a perfect combustion level of 1.0. if the level >1.0, its oxygen rich (low fuel) if the level <1.0 its oxygen poor.

With yours @ 0.81 its starved of oxygen and is allowing unburnt fuel to pass through the exhaust (the HC = hydrocarbons) . Definitely change your air filter and maybe clean your MAF sensor

djsim101

Thanks guys for your help and advice, really appropriate it.Just to give you an update. I brought it to a garage (trust these guys) who put the car up on lift. There is a hole in the CAT, right in the middle. They recommend replacing the CAT and sensor. They are trying to find the best price for me, but I am looking at 500 - 600 I think. They reckon it has a 90% chance to pass with this work done.

I know its a chance to take, but the car is reliable other than that, think I might take the chance. Cert will be valid for 2 years as well if I can get it passed by the end of this month.

Leonard Hofstadter

Good to hear. The faulty lambda value is the reason everything else is so out of spec.

As it's an oil burner it's impossible to guarantee that this will fix the problem, but in general cars don't fail their emissions if they're using oil (once the lambda value is correct) unless it's burning more than a litre every 600 miles or 1000 km.

It is surely better to spend €600 with the potential to get another two years out of it (especially if it's been reliable so far) than to give up right now and have to spend thousands to buy something else in decent condition.

djsim101

thanks captainspeed, that is my thinking behind it, it will be certified for another 2 years, although I would never sell it on to someone, as I got stung a little on this car, don't want anyone else to be stung.

I will let ye guys know whether it will pass or not :-)