Exhaust soot

[bb730]

This may be in other threads but I couldn't find the answers I've been looking for.

I just installed a corksport power series exhaust with 1 cat deleted.
What causes exhaust soot? too much fuel burnt and not enough oxegen? bad o2 sensor?

some say protege 2003.5 will always burn rich but how can this be? It's hard to imagine that it cant burn without soot.

Any input would help. Thanks.

 

[hornsfan10609]

That is normal, the MSP does run very rich on the stock tune.

 

[StealthWyvern]

The back of my pro is always coverd in soot even when it had both cats.. i imagine it will be worse here in the coming months ith no cats