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Emission / Smog test failed, O2 passed / Air Fuel failed.

Joined
30 January 2022
Messages
34
I know this subject has been beaten to death but my test result returned a pass on the O2 / Oxygen sensors but i failed the test overall due to running too rich.

I do have aftermarket headers, exhaust system and intake system. I also vape my crankcase directly to the atmosphere not returning back to the intake manifold.

I have also recently removed the battery and reset the ECU. Which i believe may be the cause?

I've searched and searched Prime and wasn't able to find the proper procedure for reseting the ECU anymore or how long it takes to calibrate Air / Fuel Maps.

I was initially under the impression:

you run the car up to temp
Remove the clock fuse under the front bonnet
wait 15 min (however the manual did say 10 seconds)
plug the fuse back in
Run the car for a further 15 min
Turn the car off and switch the ignition back on.

I thought that was job done, although the temp gauge was reading warm and i didn't take it out for a spirited drive before hand.

I also found articles suggesting it can take 100's miles to calibrate the ecu after a reset, but no sound source. Although that might work, the catch 22 is, if i failed MOT due to emissions, the car isn't road legal. I'm only legally allowed to drive it to and from the test centre.

I do have a aftermarket fuel pump thinking about it, but i get between 47-53 psi at the fuel filter, so that seems to be in range?

I think my intake temp sensor is also fairly new, which seems another common cause.

I don't believe i have a vacuum leak but I wouldn't rule it out or know how to go about it.



I do have a TCS light on, 44 but i believe that is a right rear Speed Sensor that i need to look at and not related, apart from that no other codes.

The car drives great, pulls well. Idles really nicely.

Any ideas? I'm all out and stumped.

I've got 14 days to resolve the issue before my retest expires and ordering any parts can take a week or longer to arrive.
 
I know this subject has been beaten to death but my test result returned a pass on the O2 / Oxygen sensors but i failed the test overall due to running too rich.

What kind of compliance test was carried out? The typical monitored and controlled tailpipe emissions are CO, Nox and HC. Free O2 is not part of the compliance test results. So, you need to elaborate on what you mean by failing the compliance test; but, passing O2 / Oxygen sensors. Does that mean that you somehow separately tested the O2 sensors to confirm that they are working - which is kind of hard to do if your ECU is not OBDII compliant.

Running rich usually means high HC. Can you post the actual emission test results?
 
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