Emmissions mot failure

Technical Area Engine, Transmission, Exhaust etc
2

 Hi Guys

My H reg Roadster has just failed mot on emmissions CO only 0.686 rather than 0.300 limit.

Any thoughts on how to sort this out in 10 days so I can get a retest, the garage mentioned redex?

Many Thanks

Paul

 

 

 

3

H reg should have a pre-cat test, the limit is 3.5% CO.  Your car passes easily.  Looks like they have tested your car to post-cat standards, I suggest you discuss with them.  You say its a Roadster, ie a Eunos import, this is not listed on the MOT manual so they have to test as a pre-cat model.

Alan

4

 That is really useful thanks,

5

 

Hi Paul,

Did you get it passed at the higher reading of 3.5%?  Mine has just been failed at the 0.3 level also, its a 1996 Eunos.

I’m going through various tests as we speak, air filter (new) and lambda sensor and if that fails going to try filling the tank up and then redex, worse case scenario I’m thinking a new CAT?

regards

John

 

6

 Hi John,

Due to advice on this site I now have an mot!!!, as my car was a 1991 it should have been tested at a max rate on 3.5% so they gave me a free re test.

Unfortunatley cars from 1992 onwards have to meet the 0.3% level whch you car falls into.

I did some digging around for info when I though I would need to reduce co2 levels for retest and people mentioned.

  • Do a full service, plus air filter etc

  • Try redex nad give car a good run

  • Some people mentioned using high octain fuel (e.g. tesco 99) in the tank for re test as burns cleaner?

  • Also you can get octain booster additive that may be worth a try

Personally I would give it a go for the £25 re test fee, if it fails again you know you may need to look at a new cat?

Cheers

 

Paul

 

 

 

 

 

7

 

 This is the stuff I use on every other tankful of petrol. My car has never failed since I started to use it. By the way does your engine run steady when idling?

352×640 40.7 KB

8

Hi Paul,

Firstly, congrats on the MOT!

I will definately try the redex tomorrow, not done this before, I assume it will give instructions on the bottle, probably just pour in the tank after fuel I assume.

I’ll let you know, as you say, worth the retest fee to find out before spending on the CAT.

cheers

John

 

9

 

 One bottle is enough for 4 tanks full of petrol. Don’t be too impatient as it may take 4 tanks full to clean your engine injectors.

10

Cheers Pollyanna,

I best get some miles in then!!

regards

John

 

11

Mine has only failed on “emissions” once - the emissions themselves were fine, but the lambda (oxygen in the exhaust) was too high because of a small exhaust leak.  One of the cat flanges just needed tightening.

12

 My NK1 has just failed with a .8 on the CO. they recon the CAT is shot. I’ve fitted a m]new O2 sensor and a temp sensor, new plugs and additive

It had a new cat from mxparts 6k miles ago, where do I get a decent cat? preferably hi-flow

13

 

I would contact MX5Parts and explain that your “new” cat has failed, they may replace it. At least you can get it through the MOT.

 

14

 IT PASSED Big Smile

 

with a new cat from Bm Catalysts …half the price of Mx5parts, and a heat sheild on it, which the mx5parts one didn’t have

I presume the cat had gone from being run with a duff oxygen sensor.

The new cat will be mint still next year, as it’s going on the shelf for the next nearly 12 months (decat Devil)