Hi to all ,
I am experiencing an issue with engine performance resulting in poor emissions - high CO2. I do not get an DTCs nor MIL is illuminated.
I checked data via Techstream and also made graphs of O2 sensors as I was suspecting them to be faulty. I have attached graphs that I measured.
I noted that MAF sensor value seem to be lower that standard ( I found on this forum that the idle mass flow of the 2UZ-FE is around 4.8 - 5.7 gm/sec at idle.) Mine is significantly lower around 4. I have tested MAF sensor according to Toyota workshop manual and I get reading 3,9 OHMs by approx 10 degrees Celsius. As the reference values is for 20 C I am not able to confirm 100% if my measurement is OK as by 20 celsius it shoudl be 2,19-2,67 OHms.. Resistance should be increasing by lower temperature so I assume that MAF could be Ok.. But according to measured values is not?
I was first suspecting 02 Bank2 upstream sensor but then I noted that LTFT are around 20% positive what could indicate MAF sensor issue or vaccum leak.
Can someone confirm my theory that the MAF sensor is faulty and replacing it and thus getting 4.8 - 5.7 gm/sec at idle should solve the problem? I also checked if there is no restriction in air supply and replaced air filter, but without any change.
My LC is 1998 and not supporting misfire monitor per cylinder
this could also indicate other parts poor performance , but spark plugs are new and coils don´t have any cracks on boots.
Thank you in advance for any help or advice.
I am experiencing an issue with engine performance resulting in poor emissions - high CO2. I do not get an DTCs nor MIL is illuminated.
I checked data via Techstream and also made graphs of O2 sensors as I was suspecting them to be faulty. I have attached graphs that I measured.
I noted that MAF sensor value seem to be lower that standard ( I found on this forum that the idle mass flow of the 2UZ-FE is around 4.8 - 5.7 gm/sec at idle.) Mine is significantly lower around 4. I have tested MAF sensor according to Toyota workshop manual and I get reading 3,9 OHMs by approx 10 degrees Celsius. As the reference values is for 20 C I am not able to confirm 100% if my measurement is OK as by 20 celsius it shoudl be 2,19-2,67 OHms.. Resistance should be increasing by lower temperature so I assume that MAF could be Ok.. But according to measured values is not?
I was first suspecting 02 Bank2 upstream sensor but then I noted that LTFT are around 20% positive what could indicate MAF sensor issue or vaccum leak.
Can someone confirm my theory that the MAF sensor is faulty and replacing it and thus getting 4.8 - 5.7 gm/sec at idle should solve the problem? I also checked if there is no restriction in air supply and replaced air filter, but without any change.
My LC is 1998 and not supporting misfire monitor per cylinder
Thank you in advance for any help or advice.