had my mot done a few days ago and it flew through but the tester told me its running quite rich..its a 93wrx import with a 6k ecu..

any idea what could be causing the problem?

 

I doubt it's running that rich - surely it wouldn't have flown throught the CO2 target on the Fast Idle Tests, would it? Unless you've got a couple of cats - or one really good one - fitted.

 

i know the tester quite well..that helped it get thru..

any ideas?

 

LOL. Makes sense now.

In that case the main culprit is a knackered Lambda. It should cycle voltage between 0.1 and 0.9 odd volts - check using a volt- or multi-meter. If stuck static at a voltage between these figures, then Lambda's packed up, and when they do, the ECU overfuels off boost and the engine will be running very rich.

 

or could be summat simple like a blocked air filter too

 

Yep

Also shagged plugs... knackered coilpacks (or HT leads, where appropriate).

Try checking filter first; then check lambda's voltage; then check coils/plugs...

 

ok ta, where bouts do i take the reading for the lambda?

 

Trace the o2 loom from the sensor in the drivers side manifold and it will take you to a plug with 3 wires near the MAF, 2 white and a black, the black is the signal wire
On a side note, if you do require a o2 sensor then do NOT be tempted by ebay universal cheapies, i've done 3 in under a year Just Lambda, Subaru lambda sensors, Bosch and NTK zirconia and titania sensors by post is the place you want, 3 wire universal p/n LS02

 

thanks very much. il look into it

 

Here ya go, both are 3 wire universal, one was £18 off ebay and the other was £46 from 'just lambda'. I dont need to tell you which is which, even the wiring is of a better quality