O2 Question???
O2 Question??? Need help passenger side plugs are black and drive side look brand new. Would this be caused by my O2 being bad or defective? Mods are 5.3 with headers and a tune.
TECH Fanatic
Joined: Jun 2006
Posts: 1,285
Likes: 1
From: Elgin, Il
When was the last time you changed them or have you changed them yourself ever? I imagine you did when you put the headers in but never hurts to ask. It could be a header leak causing the 02 to read false air on that bank - which would cause it to dump fuel. Could also be the 02 sensor itself. Usually they don't go bad unless your running really rich or misfiring.
You mean the O2's aren't switching?
They are bad. I got 1,200 miles out of a set of bosch sensors.
The only reason I went with bosch is because I had two random O2's from a junkyard wire nutted to the ends of the originals. Those worked fine according to hptuners scans.
Now I have denso O2's.
Yea I might get some from the junk yard this weekend that is a good idea. The passenger side seems never to move from 8XX on HP Tuners. I did throw the o2 sensor heater code one time but then I would just let them heat up more before I started the car and it never occured again. But I did noice that after a while idling at the track this past Sunday the passenger side bank would start to go into the red on HP tuners but by that time I would just turn the car off because we would have to wait so long.
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I have the same problem with my ls1, changed them today and all 4 from the drivers side were black ...passenger were ok, i am also getting backfire on deceleration?? car feels kinda sluggish and studders a bit at idle.. getting shitty mpg, btw my cats are gutted and untuned 
Last edited by Ls1Rook; Feb 7, 2009 at 04:25 AM.
TECH Fanatic
Joined: Jun 2006
Posts: 1,285
Likes: 1
From: Elgin, Il
Well there you go. Gutted cats lose power by acting the opposite as a venturi would. It actually slows down the air because the open section of cat creates a low pressure zone, slowing exhaust gases. Any codes?
I ran gutted cats for a while, no problems.
Why in the hell would you replace all four O2's if you gutted the cats though?
The black could be a fouled or cracked spark plug, bad injector, etc. Just because the O2's keep going bad doesn't mean they are the problem, sometimes something upstream causes it.
And once an untuned front sensor slows down or flatlines, it's stuck in open loop.
Why in the hell would you replace all four O2's if you gutted the cats though?
The black could be a fouled or cracked spark plug, bad injector, etc. Just because the O2's keep going bad doesn't mean they are the problem, sometimes something upstream causes it.
And once an untuned front sensor slows down or flatlines, it's stuck in open loop.
All 4 from the drivers side were black .... changed them already feels a bit better because there new but still its the same, im going to check for codes at autozone .. dont really trust that tho =\
Theres a little confusion here. The thread is about O2 sensors, apparently you're talking about spark plugs.