After removing the mufflers and pressure-tested the cats/headers I felt air coming out of the collector of the passenger's header.
I had a set of new aftermarket headers at home so I installed them. It was a pain to get the stock h-pipe sealed to these headers on the passenger's side but with the help of high-temperature silicone, I could manage it. I pressure-tested the entire exhaust system and also used soap water on the joints. I had tiny bubbles showing up at the ball joints between the h-pipes and the mufflers. I did not seal them as I thought this might not affect the emission test. All other joints did not show any bubbles.
In the meanwhile, I also set the timing to 14 degrees BTDC.
Yesterday I was back at the MOT to get the emission test done - again.
Side info: The tank was filled 50% with 95 octane (that is the lowest we can get here).
Test 1: failed.
I changed the timing back to about 8 degrees (before I changed to 14 it was somewhere in that 8 degrees area).
The values got better but the CO2 level is still a tiny bit too low and the O2 value way too high:
Test 2: failed.
Values @ idle:
I pulled the codes after the test: nothing -> only 11
So the values are not too far away from where they may be but these values tell me I am still too lean and/or have still false air coming inside the exhaust system.
Would it reduce the O2 in the exhaust gases if I would remove the smog pump hose? Or will this make the entire emissions even worse?
O2 sensors may be faulty?
Any other ideas?
I did check the temperature after the first cats with a temperature gun: the passenger's side was slightly hotter (about 65°F).
I am quite desperate as this is the last step to get her back on the road...
I had a set of new aftermarket headers at home so I installed them. It was a pain to get the stock h-pipe sealed to these headers on the passenger's side but with the help of high-temperature silicone, I could manage it. I pressure-tested the entire exhaust system and also used soap water on the joints. I had tiny bubbles showing up at the ball joints between the h-pipes and the mufflers. I did not seal them as I thought this might not affect the emission test. All other joints did not show any bubbles.
In the meanwhile, I also set the timing to 14 degrees BTDC.
Yesterday I was back at the MOT to get the emission test done - again.
Side info: The tank was filled 50% with 95 octane (that is the lowest we can get here).
Test 1: failed.
I changed the timing back to about 8 degrees (before I changed to 14 it was somewhere in that 8 degrees area).
The values got better but the CO2 level is still a tiny bit too low and the O2 value way too high:
Test 2: failed.
Values @ idle:
| CO2 | 13.07 % |
| O2 | 2.2 % |
| HC | 26 ppm |
| Lambda | 1.115 |
| CO | no values as they do not test CO |
I pulled the codes after the test: nothing -> only 11
So the values are not too far away from where they may be but these values tell me I am still too lean and/or have still false air coming inside the exhaust system.
Would it reduce the O2 in the exhaust gases if I would remove the smog pump hose? Or will this make the entire emissions even worse?
O2 sensors may be faulty?
Any other ideas?
I did check the temperature after the first cats with a temperature gun: the passenger's side was slightly hotter (about 65°F).
I am quite desperate as this is the last step to get her back on the road...