FAILED NCT
- Thread starter AndyC
- Start date
goldenjohn
Octane Boostaholics
hey andy, had similar problem with the b4, I'd too replace lambada sensor and the cat, it was all a result from a coil pack going on the car. So i'd say if you can get the loan of a cat and put it on and get an emission test done with the different cat before you go but a new cat as there 
Pricey. Buy origional subaru if needs be. 
Pricey. Buy origional subaru if needs be. johnjoe said:Does the Power FC show a lambda or air/fuel ratio? If so, what value does it give?
By my calculations a lambda of .734 would be an AFR of 10.8:1 which is very rich! Should be around 14.7:1.
And if that's just at high idle (around 2800rpm ish, is it?) then it would be extremely rich at full throttle.
If it's over fueling like that I think it would be a problem with the lambda sensor.
I wonder if the NCT equipment is calibrated correctly, because if the car is running that rich then I'd say you would notice it running a bit poor and the fuel economy would be really bad.
If it was me then I would have another emissions test done to confirm that the NCT readings are correct, and if they are, then I think it would be new lambda sensor time
Now I'm definitely no expert!So that's just my input
but I'm interested in mapping and stuff.
Good luck with it, and give us an update when you get sorted!
I'm no expert on these things but I did notice this graph is from a Toyota. Surely the AFR for a Subaru would not be the same?
If you're overfuelling and it isn't because of the Apexi settings then it could be because the air filter is blocked and the engine isn't getting enough air. You could try cleaning or replacing the air filter and checking to ensure all air intake hoses are not blocked or kinked. Just a thought
Frawls
marksscooby
Petrolheads
if your cat is gone maybe you can get a loan of it off dave in the link below
http://www.isdc.ie/discussion/index.php?topic=1543.0
http://www.isdc.ie/discussion/index.php?topic=1543.0
AndyC said:
Any readings from that emissions retest you had done? Was the lambda reading still out or just the co2 and HCs?
I think the cat in the downpipe is the only one that matters when doing the test, should be able to pass without the centre section.
As Frawls said, you should check all the intake piping to make sure there's no air leaks.
Hard to know for sure if the cat is definitely gone, wait and see what the traders say, they'll know best
@Frawls - 14.7 is the stoichiometric ratio for petrol so that AFR is the target for all petrol cars when in closed loop mode. From what I understand closed loop mode is when the ecu monitors readings from the sensors and make calculations from that. Open loop mode is when the ecu uses fixed values stored in memory. When in open loop mode the AFRs will be different as each car will have different settings for either economy or power
johnjoe said:AndyC said:
Any readings from that emissions retest you had done? Was the lambda reading still out or just the co2 and HCs?
I think the cat in the downpipe is the only one that matters when doing the test, should be able to pass without the centre section.
As Frawls said, you should check all the intake piping to make sure there's no air leaks.
Hard to know for sure if the cat is definitely gone, wait and see what the traders say, they'll know best
@Frawls - 14.7 is the stoichiometric ratio for petrol so that AFR is the target for all petrol cars when in closed loop mode. From what I understand closed loop mode is when the ecu monitors readings from the sensors and make calculations from that. Open loop mode is when the ecu uses fixed values stored in memory. When in open loop mode the AFRs will be different as each car will have different settings for either economy or power
Well you learn something new every day. Not so sure my mates in the pub will appreciate me explaining that to them later but I will anyway!
Frawls
Turbo Tony
Petrolheads
do you want my full exhaust system? cats an all,
jus passed my nct with it yesterday.
jus passed my nct with it yesterday.