Failed emissions on MOT. Car is running lean.

[KBB]

Both your idle and fast idle 4 gas test show lambda well within range proving the ECU has got very good closed loop fuel control.

Your issue is a inefficient CAT. A CAT in good condition will reduce before CAT CO by 90% as they age the conversion process becomes less efficient.

The is nothing wrong with the ECUs fuelling strategy the fault is with the CAT.

This system only runs with one up stream O2 sensor, the is no down stream CAT monitoring O2 sensor to test the efficiency.

Using a infrared temp sensor is the common approach to access condition. The temp at front of the CAT is measure and then the temp at the back and the difference is calculated.

70-100 deg difference = CAT operating under rich condition.

45-70 deg difference= CAT efficiency is good at 80%-100% conversion
30-45 deg difference= CAT efficiency is around 50% conversion
less than 30 deg difference= CAT not converting

[FossilFish]

Many thanks KBB I just change the CAT to see if it helps and delete the EGR for good measure.

[Chesh740R]

Originally Posted by FossilFish

Yes its a B230FT and it does have a EGR, I can just cover the hole with a plate (20 and close off manifold with a bolt) and discontent the vac line (4) and join 8 and 9 up.



What are the benefits and won't this increase the emissions on the NOX side?

what size bolt fits over manifold in the pic and how did you make your plate?

When I deleted it on my sport, I JB welded either a penny or 2p over the hole in the intake manifold. Removed all the egr stuff and pipe work and put a bolt in the exhaust manifold.

As for the vac pipes removed them all and blocked off the take off on inlet manifold or depending where the vac line to number 9 goes just connected that straight to manifold removing the T. Just left the part 1 on strut tower electrically connected doing nothing.

[Chesh740R]

And a lot easier to take your inlet manifold off to remove the egr stuff, and whilst your there it's also a good time to change your breather box if it's been a while since it's been changed.

[FossilFish]

@Chesh740r

Many thanks I have already cleaned my breather with petrol I hope that's good enough.

I will do as you say sir in regards to the EGR, and see you and your fine motor soon.

FANKS!

[Alasdair1]

If its any help I got a non approved cat from Yorkshire exhausts for around £50-00 last year. It went through the MOT last month no probs. Try cats4u there around £80-00 for an approved and £50-00 for non approved. If I remember the date is 2001 onwards for compulsory fitting of approved cats. The only difference in appearance is the code has an H in it.

Alasdair

[Diesel-do-nicely]

I have found a low mileage 940 to pinch a pair of nivos, 1041 axle, propshaft (for me), and theres a o/e volvo cat too, 71k miles, ft hpt manual, if u want i will remove it for you, its your best bet as after market ceramic cats from euro car prats ect are a waste of money. 2 years and they are finished.
Whatever i get charged plus £20 for my time plus postage, pm me.

[FossilFish]

Originally Posted by Diesel-do-nicely

I have found a low mileage 940 to pinch a pair of nivos, 1041 axle, propshaft (for me), and theres a o/e volvo cat too, 71k miles, ft hpt manual, if u want i will remove it for you, its your best bet as after market ceramic cats from euro car prats ect are a waste of money. 2 years and they are finished.
Whatever i get charged plus £20 for my time plus postage, pm me.

Thank you and Alasdair.

It's very kind of you to offer but I have sourced a exhaust from Chesh740R and should be picking it up soon.

Thanks for the thought your very helpful.

[Diesel-do-nicely]

Any one else needing to borrow or buy the cat get in touch sharpish, i can see the recycler taking it for processing otherwise.