[Mk2] [Turbo] Failed mot on emissions rev 3 turbo help please!

[dbiagioni]

Hey all.

Took my car for a mot today and failed on emissions
Everything else was spot on.

Anyway emission results were:
CO: 0.64 (needs to be under 0.30)
HC: 26 (under 200 so all ok)
Lambda 1.003 (between 0.97-1.03 so ok here too)

The car is a rev 3 turbo running a blitz turbo, greddy intercooler, apexi induction kit, bee r exhaust (cat still on but not for long!) The car also has an uprated fuel pump and possibly uprated injectors. Its currently on standard management but used to run a motec ecu which one of the previous owners removed before i bought it.

There is a slight smell of unburnt fuel @ idle and the car has no error codes.

Any ideas? Im thinking o2 sensor, but if it is fitted with bigger injectors on stock management would this affect CO reading? Also if it was o2 sensor surely it would throw a code up?

[Baker]

Bit confused, isnt the limit for pre 95 Co @ 3.5?

[dbiagioni]

They always end up going through a cat test when i take them, i have given up moaning that the engine code isnt in the emissions book and just put the cat back on.

This rev 3 is on a N plate

[dantheman]

if it is fitted with bigger injectors on stock management would this affect CO reading?

Undoubtedly. excessive CO is a product of incomplete combustion, ie its running rich. If the ECU is expecting 550cc injectors and has bigger ones its going to be overfueling. You have to put the stock injectors back in, change your ecu or get a fuel controller like an emanage.

[Baker]

They always end up going through a cat test when i take them, i have given up moaning that the engine code isnt in the emissions book and just put the cat back on.

This rev 3 is on a N plate

ah ok, i was going by your profile car.

[Marf]

Bit confused, isnt the limit for pre 95 Co @ 3.5?

They always end up going through a cat test when i take them, i have given up moaning that the engine code isnt in the emissions book and just put the cat back on.

This rev 3 is on a N plate

Technically it should go through a cat test. The rules are imports with no UK equiv manufactured after 1-8-95 are subject to a CAT test. N reg starts 1-8-95.

I'd say you need to find a better test station who are more errr, "understanding" and will use the "non cat" test limits.

Mine just went through the MOT with 0.62% CO and 20ppm HC. Basically stock engine with your normal bolt ons and no cat.

[marktullett]

I had the same problem last year so emailed the VOSA. This is the reply I got:
Passenger cars that have no exact match in the book and are first used between 1 August 1986 and 31st July 1995 would require a non cat test and would need to meet the following limits: CO<=3.5% and HC<=1200ppm.

Think this agrees with most others posting. I went back to the garage who tested my car with this info and they refunded the MOT.