AFR not normal

[erik ojeda]

Hello everybody, i just got my car back from the shop and i notice that my afr are not normal...on idle its at 16.4 to 18.0 and wen im driving its at 15.0 to 16.5..could be a boostleak or something else??..

 

[Macgyver'sDSM]

Could be a exhaust leak before the 02 sensor. That would be my first thing to check. Does the car run fine otherwise?

And what did they do at the shop?

 

[erik ojeda]

And what did they do at the shop?

it drives fine and on wot it still pulls

i took it to the shop to replace my headgasket

 

[curt-s]

at 16.4 to 18 idle, it would be noticably different than before and your trims would be totally out of whack on cruise if it was pre-o2. are you running narrow and wide with no simulation?

 

[erik ojeda]

at 16.4 to 18 idle, it would be noticably different than before and your trims would be totally out of whack on cruise if it was pre-o2. are you running narrow and wide with no simulation?

on idle it struggles to be on wen the car is warm... im running a aem wideband

 

[boostdawd]

What are u using to tune the car? A vacuum/boost leak will affect your afr at idle and wort as well as a pre sensor exhaust leak.

 

[erik ojeda]

What are u using to tune the car? A vacuum/boost leak will affect your afr at idle and wort as well as a pre sensor exhaust leak.

im using dsmlink v3.. wat is a presensor exhaust leak

 

[boostdawd]

A leak right before your wideband sensor. I would do a boost leak test first and go from there.

 

[erik ojeda]

A leak right before your wideband sensor. I would do a boost leak test first and go from there.

i should to a boostleak first then and go from there.. thank alot everyone i hope i find the problem

 

[curt-s]

a leak past an exhaust gasket beforr the sensor (generally manifold gasket, mani to turbine, or turbine to o2 housing) will cause the o2 sensor to read more oxygen content and attempt to increase fuel in closed loop as a result -- a false reading. however, if it cant adjust enough, you will still have a lean reading while running pig rich in reality, causing drivability issues and poor fuel economy. your STFT and combinedft will tell you of this if their numbers are really high.
are you running a narrowband in your o2 housing and a wideband in a downpipe?

 

[erik ojeda]

well i finally found the cause of the problem.. i had a mess up manifold gasket and a crack on the exhaust.. after fixing all that it finally reads normal... thanx everyone for your help..