Discussion Starter · #1 ·
Last month I did the Teamrush upgrade on my '84 CJ with the 4.2. I just got it inspected, (big deal in NY, they actually strap it down to a dyno for 15 minutes) and the sucker passed with flying colors. My problem is that this weekend I replaced the muffler and tailpipe, and 300 miles later the tailpipe is black. The motor is rebuilt, and I have the stock carter carb on it. The Jeep idles smooth, and isn't that fumey (i dunno if that's a word), but I would like to know what is causing the heavy build-up on the tailpipe.