Failed MOT - Emissions

15th May 2013, 16:54

My saxo VTR MK 2 2003 has just failed its MOT on emissions the garage said I need a new CAT and lambda sensor! I recently put a piper centre pipe and back box on it, am I right in thinking that the piper centre pipe and back will not affect the emmisions because the CAT is in the mani?

Don't have the print out for MOT yet

15th May 2013, 16:59

That's correct as far as I'm aware

15th May 2013, 17:12

So if I get a new mani it should pass ok?

15th May 2013, 17:20

Correct, but as they've said, you may need a new lambda as well.

The lambda controls the fuel and air mix. So a broken one will normally run the car rich (more fuel) meaning higher emissions.

15th May 2013, 17:43

Ok thanks lads, do mk2's have 2 lambda sensors?

15th May 2013, 17:49

Depends what emissions it failed on as to what needs changing mate

15th May 2013, 19:25

I will post the print out tomorrow

15th May 2013, 20:29

On a MK2 the cat is under the car. If you have a de-cat pipe, it will fail straight up. And i think there are two lambda sensors, one in the manifold and one underneath, but don't quote me on that

15th May 2013, 20:54

Quote:

Originally Posted by Geist

On a MK2 the cat is under the car. If you have a de-cat pipe, it will fail straight up. And i think there are two lambda sensors, one in the manifold and one underneath, but don't quote me on that

Mk2 vtr cat is in the downpipe NOT under the car.

I would personally ask them to run the emissions test and while doing that unplug the sensor. If it makes no difference chances are its just that, saving you the cost of a new cat

15th May 2013, 20:58

Quote:

Originally Posted by Geist

On a MK2 the cat is under the car. If you have a de-cat pipe, it will fail straight up. And i think there are two lambda sensors, one in the manifold and one underneath, but don't quote me on that

Your getting confused with a mk1 which has the cat under the car mate.

15th May 2013, 22:58

Quote:

Originally Posted by Geist

On a MK2 the cat is under the car. If you have a de-cat pipe, it will fail straight up. And i think there are two lambda sensors, one in the manifold and one underneath, but don't quote me on that

yea the mk1 has the underfloor cat and also one lambda sensor mk2s had it in the downpipe and two lambda sensors

16th May 2013, 11:57

Print out from test can any shine some light on it?

do i need a new cat and what lambda sensor needs to be replaced

16th May 2013, 12:28

Lambda shows the car is lean... So new lambda first (cheapest)... Unfortunately thats taken at the tailpipe so lambda 2 should be reading the same but without live data its difficult to tell what one is reading wrong... Otherwise its another cat... I have one kicking about atm, whereabouts are you?

16th May 2013, 12:28

Hasnt failed by much looking at that.

You defo need a new lambda.

Has the car been serviced in a while? maybe worth using some higher octane fuel as well...

16th May 2013, 12:41

Quote:

Lambda shows the car is lean... So new lambda first (cheapest)... Unfortunately thats taken at the tailpipe so lambda 2 should be reading the same but without live data its difficult to tell what one is reading wrong... Otherwise its another cat... I have one kicking about atm, whereabouts are you?

Will change both lambdas then, the thing is if i change the lambda's and it fails again i will have to pay another £50 for MOT test! might just play it safe and change the CAT, North West mate.

Quote:

Has the car been serviced in a while? maybe worth using some higher octane fuel as well...

No hasn't been done in a while

16th May 2013, 12:54

High emissions can be due to the car not being serviced in a while. as its not combusting the fuel to a good standard anymore.

16th May 2013, 13:11

Will take it for a service then ta mate, This should be a direct fit
http://www.ebay.co.uk/itm/CITROEN-SA...item35bfbe7afd

Or should i try my luck with one one from the scrapyard

16th May 2013, 13:20

up to you mate!

scrapyard ones are normally alright, might be worth asking if it comes with a warranty?

16th May 2013, 13:37

if i get a new one does it have to be a type approved CAT and a standard CAT? or will both pass the MOT

16th May 2013, 15:32

A type approved CAT or a standard CAT?* can't edit my post's

16th May 2013, 15:47

Quote:

Originally Posted by II-AnDo-II

Will change both lambdas then, the thing is if i change the lambda's and it fails again i will have to pay another £50 for MOT test! might just play it safe and change the CAT, North West mate.

No hasn't been done in a while

I'd ask them to run an emissions test before the MOT again. Saves paying again if they haven't sorted the problem.

If it's only slightly over have you tried giving the car a good thrash before hand?

16th May 2013, 16:53

Looking at that sheet, I personally wouldnt be changing the CAT.

Relatively low HC with high CO = rich mixture (probably faulty pre cat lambda)

Get them both changed (about £25 for Bosch or NTK and change your connectors over) and you will be ok.

16th May 2013, 19:32

Quote:

I'd ask them to run an emissions test before the MOT again. Saves paying again if they haven't sorted the problem.

If it's only slightly over have you tried giving the car a good thrash before hand?

Ye good shout! Ye will give it a good blast out! It was cold last time

Quote:

Looking at that sheet, I personally wouldnt be changing the CAT.

Relatively low HC with high CO = rich mixture (probably faulty pre cat lambda)

Get them both changed (about £25 for Bosch or NTK and change your connectors over) and you will be ok.

Thanks mate, guna get both lambada's change service it an give it a good run out. Will let yas know how I get on

17th May 2013, 14:14

Where the best place online to buy the 2 lambda sensors from? they are a rip-off locally

17th May 2013, 18:10

ecp or gsf probably.

18th May 2013, 07:22

Ebay : Bosch Universal Lambda Sensor ... is the cheapest option

You will need to (or get someone else) to cut and solder your original connectors on though, but it will save you load this way. Make sure the connected wires are completely water proof when you join them up

4th June 2013, 22:43

Help....My son's saxo has failed it's MOT on emissions. It's had a new cat, complete exhaust system and both Lambda sensors changed, but still running rich. Any ideas?

4th June 2013, 23:04

engine temperature sensor possibly, or map sensor.

but before throwing money at it, get a proper diagnostic check done, that will narrow it down greatly.

5th June 2013, 08:08

Get it serviced properly, air filter / oil / spark plugs

6th June 2013, 07:26

^^ Like above, you can service it yourself using top quality oil and genuine parts for less than £60 and an hour or 2. Example links here.. Click click click...

Then really if you know someone relatively cheap, youd want to have it plugged in incase something stands out as faulty, rather than just keep replacing sensors.

7th June 2013, 19:02

My mk2 has 1 lamda sensor in the downpipe and the cat is under the car.

7th June 2013, 19:21

Quote:

Originally Posted by outrage_uk

Ebay : Bosch Universal Lambda Sensor ... is the cheapest option

You will need to (or get someone else) to cut and solder your original connectors on though, but it will save you load this way. Make sure the connected wires are completely water proof when you join them up

Not having a go but i`ve been told its not wise to start soldering lambda sensor wires mate.