Evening All,
I wanted to share my recent experience at MOT time....
Having had the car from new until now, it's seen a fair few MOTs since 2000, last couple of years the emissions have been close...
Had a replacement CAT done several years ago....
Had my guy (who's looked after the car at Toyota and now at Toyotek, his own company).... on the diagnosis, whilst the current 02 sensors didn't throw the engine management light, they where lazy O2 sensors..... which caused it to fail on emissions....
I'm not technical, but the should switch the keep the mixture of fuel correct, but the switching was lazy... replacing both 02 sensors from Sparkplugs.co.uk - costing about £50 each, with next day delivery - £110.00....
result.... the car flew through on emissions with the 02 sensors switching correctly....
so for anyone struggling with the emissions, this could be an inexpensive fix and in addition, the correct switching will stop over fueling.
Hope this helps others who may be heading for the MOT station with emission issues.
Cheers
Darren
New ticket... roll on 2019 and my 19th year of ownership :)
Often forgotten. Point well made.
People think that as long as there's no error code, it's OK.
O2 sensors age and become less effective in their catalytic processes, causes them to be slow to react to changes in o2 levels. Even worse, they become more sensitive over time to hydrocarbons and carbon monoxide and use up oxygen in the o2 sensor to convert these to other components, making the o2 read rich, and thus the car cuts fuel... Not good for a clean burn and emissions.
I'm a fart so I always have my fuel trims and o2 readings at hand so I can see when they're starting to become unusable.
But as Darren said, if all else is OK and the car is struggling with emissions, ask yourself when the last time was you changed those sensors. I'd say they have a life span of 50k as an absolute max.