Stft2% is always much higher than stft1%

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Rob09msport

Rob09msport

Major
Valve cover have a crack? It can allow funny things if it's cracked internally. This is because of the ports in the heads which allows boosted intake air to interact with pcv air
 
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Rob09msport

Rob09msport

Major
I mean valve cover their are internal chambers so they can leak and you wouldnt know except for anomalies. Question how quick do your lambdas drop to full lean and is their a difference between how long it takes if you go from boost to no throttle vs light throttle "no boost" to no throttle and have your afr read 235 or whatever the exact number is I dont remember off top my head
 
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C

CC-Z435IS

Lurker
Rob09msport said:
I mean valve cover their are internal chambers so they can leak and you wouldnt know except for anomalies. Question how quick do your lambdas drop to full lean and is their a difference between how long it takes if you go from boost to no throttle vs light throttle "no boost" to no throttle and have your afr read 235 or whatever the exact number is I dont remember off top my head
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yeah ，around 235
 
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Rob09msport

Rob09msport

Major
Yes but take log of letting off throttle and how long it takes for you to hit 235 I had same issue and it was valve cover if I was off boost like very light throttle everything showed fibe if I hit boost then let go my one bank would be lazy like bad injectors but they were brand new. Turned out was my valve cover. Also how old are your o2 sensors and obviously like was already posted turn off meth until your done troubleshooting so you reduce variables.
 
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C

CC-Z435IS

Lurker
Rob09msport said:
Yes but take log of letting off throttle and how long it takes for you to hit 235 I had same issue and it was valve cover if I was off boost like very light throttle everything showed fibe if I hit boost then let go my one bank would be lazy like bad injectors but they were brand new. Turned out was my valve cover. Also how old are your o2 sensors and obviously like was already posted turn off meth until your done troubleshooting so you reduce variables.
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I can understand what you mean, thank you very much, I will try to change the valve cover tomorrow.
 
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Rob09msport

Rob09msport

Major
While you have it off might want to do carbon cleaning if it's a mess since will be apart. If your logs look like what I described and it happens with meth off I would be confident in the valve cover but please check. I would never want to make you do something if is not necessary but honestly anyone on this platform will tell you do the valve cover cause they suck and dont last very long so better now than later.
 
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C

CC-Z435IS

Lurker
Rob09msport said:
While you have it off might want to do carbon cleaning if it's a mess since will be apart. If your logs look like what I described and it happens with meth off I would be confident in the valve cover but please check. I would never want to make you do something if is not necessary but honestly anyone on this platform will tell you do the valve cover cause they suck and dont last very long so better now than later.
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I have run this car for 50,000 kilometers. I just changed the PCV valve, but there is no change. I think it is feasible to replace the new valve cover.
 
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