Sludge in catback?

[Greybush]

So I have an 89 coupe with a ka24de and 5 speed swap. It's been running really rich and smoking all over. It is running some sort of auto ecu. But point it I took off my silencer too see how it sounded for the fun if it, and all of a sudden all this black sludge in there. Would this be caused by the running rich or what?
http://i1207.photobucket.com/albums/bb471/Bailey_Brotator_Sammet/3370B6FE-DF87-46CA-9DD0-D8596A590DC3.jpg (http://s1207.photobucket.com/user/Bailey_Brotator_Sammet/media/3370B6FE-DF87-46CA-9DD0-D8596A590DC3.jpg.html)

[Chaluska]

yes. definitely

[Greybush]

Thank you! Just wanted to make sure it wasn't something else I would have to worry about.

[!Zar!]

That looks milky.

Like a combination of coolant and oil.

Is your compression good?

[Greybush]

Not sure. I can most likely do a compression test this weekend to look.

[Greybush]

So did a compression test finally. Results weren't good.
200, 175, 175 (drumroll) 30