Check engine light after cat back exhaust VF Sv6

[Spectre sv6]

Put a black ops performance cat back exhaust 2.25" on. Kept all the sensors. Took it for a drive and the whole thing was smoking a lot, i put this down to any oils in the paint or even maybe in the pipes itself. 95% of the smoke is gone and now when i start it (the next day) i get a slight smell of the same smoke but i cant see any. Anyway the check engine light is now on and i was wondering if u guys had any ideas or experience as to why or how i can fix it.

 

[DavesSV6Tonner]

Put a black ops performance cat back exhaust 2.25" on. Kept all the sensors. Took it for a drive and the whole thing was smoking a lot, i put this down to any oils in the paint or even maybe in the pipes itself. 95% of the smoke is gone and now when i start it (the next day) i get a slight smell of the same smoke but i cant see any. Anyway the check engine light is now on and i was wondering if u guys had any ideas or experience as to why or how i can fix it.

Put the original cats back on .

 

[Spectre sv6]

Put the original cats back on .

Oh any reason i should be aware of?

 

[DavesSV6Tonner]

I was once told by an exhaust shop that the post CAT 02 sensors on the Alloytecs often throw up fault codes with aftermarket CATS.
Don't know how true that is but they reckoned they have seen it quite often.
Fortunately my 04 VZ only has pre CAT 02 sensors so they said aftermarket CATS would not present any problems on my 1 Tonner.

 

[vr94ss]

Old thread but for history's sake, I would suggest resetting ecu(disconnect battery for 15-20 mins) and letting it relearn. Not only aftermarket exhausts but OTR intakes can throw check engine at you. If after a few hundred Ks after resetting ecu it still happens, either revert mods or get it tuned with the mods.