Cadillac V-Sport General Discussion Discussion, Vsport quirks and problems in Cadillac CTS V-Sport; Originally Posted by WOT-Tuning
I realize the soot issue discussion is a couple pages back, but I had some comments ...
I realize the soot issue discussion is a couple pages back, but I had some comments about it. It, for better, or worse (sounds like worse based on the discussion here) is a by-product of the fuel injection strategy used during cold starts. The engine controller injects fuel during the exhaust stroke to light the catalytic converters off super-quick for (overall) reduced emissions. This only happens for about 30 seconds or so after a cold start, but while it is occurring, visible smoke / soot can be seen and the exhaust smells terrible.
Its a phenomenon largely isolated to DI (direct injected) engines (because MPFI engines can't inject fuel during the exhaust stroke with the intent of sending unburned fuel into the exhaust system) and is commonly mistaken for an improperly tuned engine. There's GM bulletins about this as well.
Still, it'd be nice if we didn't have to deal with it!