transamws6_97

iTrader: (5)

Okay back when I did longtubes and duals I had a local tuner do a street tune on my car. Last year I had it on a dyno and they read the a/f ratio around 12.5- 13 up to around 5k rpm then went a lil rich down to 12.0 above 5k. Well going to work a few weeks ago a coworker was behind me and said when I got on it he could see black smoke coming out of my exhaust and could smell it. Went WOT yesterday while looking out my side mirror and saw a black cloud when I got on it. What could be causing me to run rich? I'm still getting decent gas mileage and its running fine. Could I need to go to the tuner and have it retune it?

mrchyzy16

iTrader: (1)

I would say re-tune. You shouldnt be getting any black smoke at all. Your running rich.

speed_demon24

iTrader: (6)

Detonation causes clouds of black smoke too fwiw. I would leave trails of black smoke on my mail order tune with an a/f in the low 13's, got dyno tuned and pulled a bunch of timing and no more smoke. 12:1 a/f shouldn't be rich enough to cause plumes of black smoke.

transamws6_97

iTrader: (5)

i dont think i am getting any detonation. my engine isn't knocking. It didn't used to blow smoke out the back. The only thing different between this setup and when it was tuned was i gapped my spark plugs a little closer.

mrchyzy16

iTrader: (1)

what did you gap them too?

transamws6_97

iTrader: (5)

.035 but they were previously .055 and it seemed like my idle was a tad rough so thats why i closed the gap some

mrchyzy16

iTrader: (1)

.035 is too much i think. Stock gap is .050. I would stick around there or maybe .045. Unless you have a cam then .035 could be your problem right there.