1994 2.0 WRX with high emmisions

[lost in espace]

I have seen a WRX for sale that failed its MOT on high emissions. Its got an Scorpion exhaust which I presume means no cat. The vendor thinks its a faulty spark plug or injector.

Is this a common problem? I am not sure how far it is over the limit at the moment.

[ScoobieWRX]

Having a fully decat exhaust system in the UK means you will fail emissions testing. The only way around that is to have your car tested at a decat friendly MOT center!!

If it had a catted exhaust system then emissions falure would be either a faulty O2 Sensor or MAF sensor.

Edited to add: A faulty spark plug might fail emissions testing if it isn't firing and combusting cylinder contents thereby chucking unburnt fuel straight down the exhaust. The only time i could see injectors causing emissions issues is if it's flowing too much fuel into the cylinder (running rich), again chucking unburnt fuel down the exhaust.

The decat exhaust isn't a common problem...it's just the way we like it O2 sensors break down as do MAF sensors, it's just one of those things. Dodgy spark plug...is just a dodgy spark plug, and generally speaking Subaru injectors run very well, not normally a problem as far as i know.

HTH

Edited by ScoobieWRX on Thursday 25th June 12:07

[markCSC]

Hello

If your interested get a copy of the fail sheet to see what it failed on. However if it has failed an MOT and the owner hasn't fixed it what does it say about the rest of the car??

Oh and O2 sensor cost £150 for the main dealer
MAF can be up to £300 depending on what model it has

Mark

[lost in espace]

Thanks for the tips Mark, appreciated.