Does the EW10J4 fail emissions test with no cat fitted?

[Jabo]

Hey guys

I have the EW10J4 2.0 litre petrol in my Citroen C5 and my cat might be semi blocked (twice now I've had catalytic converter error messages)
Does this engine usually fail emissions tests with a decat pipe?

[spider]

Most if not all petrol engines will fail a cat test (post 91) without a cat fitted unfortunately.

Those with dual sensors are likely to throw up faults too (as the ECU checks the gas before and after the cat) although a single oxy sensor setup will not throw up any faults.

[Jabo]

Most if not all petrol engines will fail a cat test (post 91) without a cat fitted unfortunately.

Not true. I've had various post 1991 Rovers in my time pass the emissions tests with no cat. Just had to be warmed up prior to going to the test station.

A car can fail emissions test with a cat fitted just as some cars can pass with no cat fitted.
Cats are fitted as it's a legal requirement for all cars, not because it's required to bring the emissions down.

[Jabo]

C5 does have the twin sensor setup though. That will probably make it a no-go.

[mlkey]

Under the new 2012 MOT changes which came in from the 1st January, a catalytic convertor fitted as original equipment but missing will be a reason for failure. You can read about changes at http://www.theaa.com/motoring_advice/ca ... -2012.html" onclick="window.open(this.href);return false;.

[Northern_Mike]

Under the new 2012 MOT changes which came in from the 1st January, a catalytic convertor fitted as original equipment but missing will be a reason for failure. You can read about changes at http://www.theaa.com/motoring_advice/ca ... -2012.html" onclick="window.open(this.href);return false;.

What about something that looks like a cat, but has had the innards smashed out of it, yet still passes the emissions test?

[Jabo]

The MOT tester doesn't have the right to remove anything for inspection though so there's no way for him to tell if it's a decat pipe, a sports cat, an OEM cat with no guts or anything else. You'd need to tell him "by the way, that's not a catalytic converter"

[Deanxm]

no you wouldnt because you would have an eml light on, the downstream Lambda probe would detect a non functional cat.
My XM will pass its test with no cat and has done BUT any car registered after August ?th 1992 must be fitted with a catalytic converter, as mentioned above with these early single lambda systems you could smash the guts out and if the engine is in good condition it will pass but you can forget it on later obd2 compliant vehicles.

The question i would be asking is whats gone so badly wrong with your engine to make it poison the cat all the time.......................they should last forever within reason.

D

[citronut]

how come then the MOT station i use can tell by the emmision result, if it has faild due to the cat or the labada sensor at fault,

regards malcolm

[Jabo]

how come then the MOT station i use can tell by the emmision result, if it has faild due to the cat or the labada sensor at fault,

No cat increases the carbon monoxide output. Lambda sensor reads the oxygen output.

The question i would be asking is whats gone so badly wrong with your engine to make it poison the cat all the time.......................they should last forever within reason.

It's 11 years old and suffered over the last year with very unoccasional misfires due to a slight oil weep into the plug bores. It was diagnosed as a dodgy ignition coil first then dodgy spark plugs.


Looks as if a sport cat will be the way to go.

[Deanxm]

because they do a natural idle to test the lambda probe switching and a fast idle to light the cat up (thinkits that way round) and see the co limits and depending on how the levels change they know what part is responsible, in theory, so long as there are no vac leaks/engine faults etc.
Age of car is also very important as mot co limits fell over the years, some old dino like the xm has rather lax limits whereas a 2000plate will have tighter limits.

Interestingly if say a 2010 plate car is fitted with a 1970's engine and you can prove the engine is the age you say it is the emmissions test must be based on the limits for the age of the engine not the car.................so if you fancy shoving a small block chevy into a prius it will pass its mot, apparently

[Deanxm]

how come then the MOT station i use can tell by the emmision result, if it has faild due to the cat or the labada sensor at fault,

No cat increases the carbon monoxide output. Lambda sensor reads the oxygen output.

The question i would be asking is whats gone so badly wrong with your engine to make it poison the cat all the time.......................they should last forever within reason.

It's 11 years old and suffered over the last year with very unoccasional misfires due to a slight oil weep into the plug bores. It was diagnosed as a dodgy ignition coil first then dodgy spark plugs.


Looks as if a sport cat will be the way to go.

Have you tried some cataclean?.

D

[Jabo]

I haven't tried it but I think I will. Looks pretty good.

[Deanxm]

Cant do any harm i guess, so long as raw fuel didnt make it into the cat and overheat it it should live again, if cataclean does what it says on the tin.......................

D

[spider]

Not true. I've had various post 1991 Rovers in my time pass the emissions tests with no cat. Just had to be warmed up prior to going to the test station.

A car can fail emissions test with a cat fitted just as some cars can pass with no cat fitted.
Cats are fitted as it's a legal requirement for all cars, not because it's required to bring the emissions down.

Really ? Had not heard of that to be honest.

I had tried one of the newer Ecotec Corsa's (the 3 cyl one) with no cat and it failed. I would of thought that tiny engine and a modern, new design might of made it.

I'd sort of err on the side of caution though as if it passes without a cat the mixture must be a bit too weak.