just had an mot HELP

[mlawlan69]

I bought a mk1 underfloor cat and pipe for my saxo in order to see it through the MOT.

I have come to realise however that there is only one lambda plugged in to my exhaust system, the post lambda is in my raceland 421 at the bottom of the pipe, the second lambda is in a gmc sleeve i recently bought.

The tester looked at me confused as to why it wasn't in after the cat, he then said it absolutely stank of fumes at the back (truthful tbh) and that he wasn't even going to bother wasting the extra ten minutes running it on the machine when it was obviously not going to pass.

i have not a clue what to do now, MOT is out Tuesday and i need my car for work and shizznay.

decat is a stupidly common mod for us spaxo drivers, so i need to know what people are doing in order to get it through, WITHOUT reverting my oil filter set up and putting on my mk2 manifold/cat.

[Daz_Kez]

I bought a mk1 underfloor cat and pipe for my saxo in order to see it through the MOT.

I have come to realise however that there is only one lambda plugged in to my exhaust system, the post lambda is in my raceland 421 at the bottom of the pipe, the second lambda is in a gmc sleeve i recently bought.

The tester looked at me confused as to why it wasn't in after the cat, he then said it absolutely stank of fumes at the back (truthful tbh) and that he wasn't even going to bother wasting the extra ten minutes running it on the machine when it was obviously not going to pass.

i have not a clue what to do now, MOT is out Tuesday and i need my car for work and shizznay.

decat is a stupidly common mod for us spaxo drivers, so i need to know what people are doing in order to get it through, WITHOUT reverting my oil filter set up and putting on my mk2 manifold/cat.

Take it to a decent tester who's vision and smell will become impaired for a small fee.
Plenty of 'friendly' testers about! Safe to say there's more money in it :-)

[mlawlan69]

Take it to a decent tester who's vision and smell will become impaired for a small fee.
Plenty of 'friendly' testers about! Safe to say there's more money in it :-)not an option sadly.

[Daz_Kez]

not an option sadly.

If you needed the car that badly its an easy option.. Sounds like you need to fit the post cat lambda after your cat and the pre cat lambda into your raceland.

Either way you're going to be doing a lot of messing around for effectively nothing if you're just putting a de-cat back on after your MOT.

[mlawlan69]

If you needed the car that badly its an easy option.. Sounds like you need to fit the post cat lambda after your cat and the pre cat lambda into your raceland.

Either way you're going to be doing a lot of messing around for effectively nothing if you're just putting a de-cat back on after your MOT.

the thing is my pipe doesn't seem to have a lambda hole AFTER the cat, which is why i am so confused!!

[SnakeVTR]

He should still have performed an emissions test, then you receive a printout to prove that it actually IS above the limits. If you had a cat fitted and the cat internals are in good condition and the ecu has a reading of the emissions before the cat and the second lambda is sleeved in effectivly fooling the ecu into thinking the catalytic converter is working perfectly then there is good chance the emissions would be ok as there is a cat fitted and the sensors are reading the values that they should :y:

[Daz_Kez]

the thing is my pipe doesn't seem to have a lambda hole AFTER the cat, which is why i am so confused!!

Did mk 1s have a lambda after the cat? I forget where it was positioned along the exhaust..

I suppose you could get a threaded insert welded in after the cat for some pennies!

[mlawlan69]

He should still have performed an emissions test, then you receive a printout to prove that it actually IS above the limits. If you had a cat fitted and the cat internals are in good condition and the ecu has a reading of the emissions before the cat and the second lambda is sleeved in effectivly fooling the ecu into thinking the catalytic converter is working perfectly then there is good chance the emissions would be ok as there is a cat fitted and the sensors are reading the values that they should :y:

well, that does sound correct ha, going to go back down and have a chat with them tomorrow then :)

but it does stink of petrol which is what led me to believe it wouldnt pass

[Daz_Kez]

Also I thought with the second lambda sleeved it will still over fuel a little as te second lambda will be reading no emissions thus meaning more fuel? Could just be me chatting shit though!

[devilsadvocate]

How could he possibly know it won't pass without testing it?

I would try another garage.

[Rowan]

The first lambda sensor is the one that actually "does something", the second (after the cat) is just to make sure that the cat is working properly. so if the emission is not good with the first lambdasensor in place there is something wrong with the fuel/air mixture or sensor itself

[Wee_monkey1987]

your primary lambda must b shagged then if you've got high hydrocarbon smell coming from the exhaust try switches the two lambdas over and seeing how the emissions on the back are!

[jware92]

Post cat lambda doesnt affect emissions atall, just there to tell you if the cats working

[mlawlan69]

thanks for all the replys lads, taken it back down and as expected it failed, miserably.

don't have a scanner but some figures to mull over.

fast idle test:

co: < 0.30%vol
actual: 3.78%

hc: <200ppm vol
actual: 240ppm vol

?: 0.970-1.030
actual:1.198

2nd fast idle test

co: <0.30%vol
actual: 4.43%vol

hc: <200ppm vol
actual: 345ppm

?: 0.970-1.030
actual: 1.194

natural idle:

co: <0.50% vol
actual: 3.32%vol! !

taken it to another garage whom my neighbour recommended and he said the lambda
could be fucked and to get fresh plugs in it.

lambda sensor from citreon is just short of £200

so yeah, modding cars is such a fucking ball ache!

[mlawlan69]

bump.

do the above figures coincide with a broken lambda sensor then?

will purchase a new one tomorrow along with fresh plugs if this is the case.

otherwise come tuesday, im MOTless :(

[Daz_Kez]

From what people said you could switch your primary lambda with your secondary and see if it runs any leaner?

I had a feeling I was wrong above with the second lambda theory! But if you could switch lambdas that would be a start.. After all no point killing a brand new lambda if the car has issues fueling elsewhere! :-)
Worth a try.

[jeffchiz]

Are you SURE your mk2 manifold doesnt fit with the mk1 filter??

[blackie_2k5]

thanks for all the replys lads, taken it back down and as expected it failed, miserably.

don't have a scanner but some figures to mull over.

fast idle test:

co: < 0.30%vol
actual: 3.78%

hc: <200ppm vol
actual: 240ppm vol

?: 0.970-1.030
actual:1.198

2nd fast idle test

co: <0.30%vol
actual: 4.43%vol

hc: <200ppm vol
actual: 345ppm

?: 0.970-1.030
actual: 1.194

natural idle:

co: <0.50% vol
actual: 3.32%vol! !

taken it to another garage whom my neighbour recommended and he said the lambda
could be fucked and to get fresh plugs in it.

lambda sensor from citreon is just short of £200

so yeah, modding cars is such a fucking ball ache!


if you hear a long beep...please call an ambulance :fcuk:

[mlawlan69]

Are you SURE your mk2 manifold doesnt fit with the mk1 filter??

100% no. but its a lot to do to find out it doesn't actually fit, and I would assume that it doesn't given the size of it!

[jeffchiz]

id give it a go only takes me 10min to whip an exhasut manifold off :afro: if you think yours is hard, try taking the 2 exahsut manifodls off my BMW we lifted the engine out slightly to get them out ha

[Cam]

id give it a go only takes me 10min to whip an exhasut manifold off :afro: if you think yours is hard, try taking the 2 exahsut manifodls off my BMW we lifted the engine out slightly to get them out ha

:homme:
In theory yer....

Edit: that was intended before you added on the BMW part.

[mlawlan69]

I May have to go that drastic it May seem.

just can't see it working however, but if it does then that's cool ha.

[Cam]

^^ Best off using the size 1/2" socket/spanner for the nuts if you got one that its. 13mm dont fit as smug and it hurts when you smack the slam panel :(

[jeffchiz]

:homme:
In theory yer....

Edit: that was intended before you added on the BMW part.

i remember the good old days it took me 2 days to change my exhasut manifold lol now pulling the engine out to gain extra access to certain parts seems like a small job top me now lol

[Cam]

i remember the good old days it took me 2 days to change my exhasut manifold lol now pulling the engine out to gain extra access to certain parts seems like a small job top me now lol

I know the feeling mate i tell you!

[blackie_2k5]

i actually prefer my engine out if i need to work on it

makes it quicker for me as well :o

[mlawlan69]

your all lucky, i live on a main road and bus route, simply changing a wheel can be fucking dangerous when a double decker comes hurtling past :(