Hi,

I have a '95 Impreza WRX Wagon, totally standard.

I took it for MOT and it failed on CO emissions, they also said the downpipe was leaking.

I've put on a second hand cat/downpipe and took the car for a blast with V-Power and Cataclean before retest.

It's failed again, on fast idle the CO was about 5%, HC>200, and lambda 0.8.

So it's running very rich.

Can anyone tell me what/how to check?

Lambda sensor?
MAF?
Temperature sensor?
Anything else?

I don't know when the plugs were last done so I'm going to order some, if there is any way to tell if the lambda is OK I'd like to know before I spend £80 or whatever on a new one.


Thanks very much.

 

go on you tube, how to test a 02 sensor,
but you can do it incar find the wires from 02 under the bonnet there will be 3 2white 1black then get a voltmeter set to 0to1volt and probe into the black signal wire and earth the meter, start her up should read about 0.24volts cold as soon as car warms up the meter should go up n down like a fiddlers elbow, if it dont its firked

 

did you reset the ecu after putting the new pipe on is it still compensating for an older issue and not re learnt yet ?

 

Sounds like lambda sensor. Em light not on?

 

Or the 2nd hand cat is no good?

 

mafs fail and are not too much plus don't show a cel but i would still reset the ecu

 

Find a friendlier test center.

Totoally standard classics will struggle on current emissions regs.

 

Already offered to help . . .

 

i also agree with above 1 yes the second hand cat is probably no good as it's likely to be as old as what you replaced it with and 2 emissions wise they are not easy , a good hard drive to warm it up before the emissions test should help , i get the same issue on my monaro and that's normal to expect that , a hot cat generally gets me through