hoplite

Guys and gals... Need some desperate help here....

2008 Cobalt SS Turbo LNF ---- Injen CAI ----- ZZP Catless downpipe with angled 02 bung-----

Above is what my car has otherwise it's compeltely stock, bought a new oxygen sensor (downstream) because the code is throwing p0137 for oxygen sensor bank 1 sensor 2 low voltage.

I also get one for bank 1 sensor 1 stuck lean and have terrible black smoke upon acceleration.

I replaced my downpipe with ZZP's catless and have had the code since, the downpipe does have an angled 02 bung as well, i think it's a defouler.

Checked wiring, looks ok, pigtails look ok, and it's a brand new oxygen sensor.

Car is on stock tune as well but just need this stupid light to go off and my car to run normal again, cause it kind of misses every now and then and my MPG drops.

Any ideas or help would be greatly appreciated!

Crav3

iTrader: (1)

I think you need to tune your car after those mods. I Tuned a 2015 silverado where he had misfires and black smoke with loss in power after going catless. After removing the code for O2 sensor 2 the truck ran better. Just corrected the fueling a bit and truck ran better than before.

jdbaugh1

iTrader: (1)

What all codes are you getting? Are you setting a code for the pre-cat o2 sensor like you said here? Like Crav3 said your tune could just be so far out of wack that it is throwing those codes.

Did you replace the rear o2 sensor AFTER you threw a code because of the downpipe or before? Just trying to figure out how many variables you messed with at once. If I am understanding you right you had NO codes before installing the downpipe, then you installed the downpipe and threw a code for "lean" on the front sensor and "low-valtage" on the second sensor so you then replaced the second o2 sensor and are still getting the same code?

cobaltssdude420

It's kind of obvious that you need a tune after removing your cat no? Just putting it out there lol

ECaulk

iTrader: (6)

No need to tune for those mods, you can run stock with no significant issue.

The big issue is the code for wideband (bank 1 sensor 1) stuck lean, it's likely your wideband sensor needs to be replaced.

Also it's difficult to know what you mean terrible black smoke on acceleration, unfortunately terrible isn't a good indication of quantity since it's different for everyone. Are we talking coal rolling black smoke? or just some black smoke when you punch it and then it seems to dilute

hoplite

Got it figured out guys, was a defect in the 02 bung on the downpipe, had a pretty nice size hole in it from ZZP, got it welded shut and light is now off and has been for past 250 miles, problem solved! Thanks for the input everyone!