Black smoke - O2 sensor bad?

[P11SR20DET]

My GTiR DET is smoking black, and not idling properly. It has been throwing some black residue from the exhaust for some time now. We pulled the plugs (iridium bkr7 installed about 4-5 weeks ago) and they appeared black. It seems there is too much fuel being metered in. Could this be due a bad O2 sensor? Or IACV ? MAF? Coolant temp sensor? Without a diagnostic, is there any way to check the O2 sensor?

 

[steve963]

i think if you disconnect it the car should run of the map values which are set to about 14.7

 

[jambo_gtir]

you can do a diagnostic check yourself i believe? have a search on here mate; something to do with getting the ecu to flash you a certain code on the dash. I use my laptop and nissan datascan so not sure how to do it manually.....

 

[jambo_gtir]

http://www.gtiroc.com/forums/showthread.php?t=20463
there it is... that should tell you if a sensor is gone.

 

[Fast Guy]

MAF is the most likely candidate, but it could be the O2 sensor, or maybe something else.

 

[P11SR20DET]

Turns out it was the dam MAF jack was a bit loose. :doh: It's back to normal now. Although, there is still a small bit of blackness in the exhaust. I am thinking it could really be the O2 sensor starting to go bad..??

 

[PobodY]

I'd say it was residual from the MAF. The ECU doesn't actually pay much attention to the lambda sensor, except when you're idling (when you're off the bottom of the map and on a closed-loop).