Hi, took my 155 for its MOT last week, and it failed on
- Exhaust Emissions carbon monoxide content at idle excessive.
- Exhuast Emissions carbon monoxide content after 2nd fast idle excessive.
- Exhuast Emissions lamda reading after 2nd fast idle outside specified limites.
Since this failure,
I have now changed the oil for new GTX Magnatec.
New oil filter.
New Spark Plugs.
K&N filter cleaned and re-oiled.
Air Flow sensor, encorporating air temperature sensor.. all cleaned throughout.. dirty previously, also opened up and adjusted the potentimeter arm inwards very slightly so it is not running along worn carbon tracks. Then checked the resistance and as the vane moved values gradually increase - going to recheck the values are within tolerance tomorrow, never touched the adjustments though with the spring and screw.. as these I imagine are finely calibrated in the factory and should never need changing.
Cleaned the throttle body.
Checked the throttle position sensor.. seems fine values gradually increase.
cleaned out the inlet manifold.
checked the fuel pressure regulator, it holds 3 bar fine and any excess pressure is released.
checked the injectors for leakage, when disconnected and engine is cranked.. none leak.
tightened up the rubber bits which join the inlet manifold to the head to ensure no vacuum leaks.
Also cut the ends of the rubber pipe connecting the Fuel pressure regulator to the inlet manifold to ensure no vacuum leak.
cleaned out the idle speed control valve. Seems to be operating fine.
Catalytic converter was renewed last year after the same failure points were made on the MOT.. I suspect the vehicle was only given a visual inspection and upon noticing the new Catalytic converter and lambda sensor the inspector just assumed emissions problem was cured. I did not take the car for MOT... nor this time so I do not have a print out of the emissions.
Same with the lambda sensor - replaced last year.
New Coolant Temperature sensor.
Checked the Purge solonoid on the carbon canister and it can be heard activating and de-activating upon ignition. So this is working.
Leads replaced recently.
Fuel Filter will be replaced.
Drained the fuel, replaced with BP Ultimate, and shoved in some fuel system cleaner, for the injectors etc
Somebody wants £50 to come out to do a mobile emissions test..So Im just going to take it for another MOT and hope for the best..
If anybody else has any sugestions on what could be causing my problem with the emissions it would be greatly appreciated
..If it fails again after checking the above and doing the work I have I will be completely baffled as to what the problem is.
Trying to keep the car on the road as it would be a shame to scrap it but dont want to keep spending money trying to guess the fault... car drives fine, idles ok, and has no problems with the running of the engine, no flat spots or anything.. apart from this stupid emissions problem.
Thanks for any sugestions, or help in advance
..hopefully will be able to keep another 155 on the road!