has anyone seen this?

[m'ssil80]

well i have a 91 240sx with a redtop sr20det in it and noticed something wierd. when i first start it and its cold it starts to spit small black spots out of the exhaust. it doesnt run bad or anything it just kind of rains this black stuff for a few minutes and i was wondering if anyone has experienced this or know what it might be. i did just change the plugs to one step hotter ( they were 7s but i dont run that much boost so i changed to 6s) and thats when it started to do it. the old plugs did have ALOT of carbon on them, though. it doesnt smell like anything and its not oil from my turbo, because i checked the IC pipes and everything is clean. i included some pics at the bottom anyone have any ideas? thanks.

[redtop91]

Looks like your SR spitting out some carbon deposits. Mine did that when I first got it up and running. I'd recommend seafoaming the motor once you are going to change plugs and oil again.

[m'ssil80]

what it be a bad idea to do it now? i just changed the oil, filter, and plugs like 3 days ago, and how does the seafoam work? thanks.

[redtop91]

No it'd be a bad idea to do it now. Seafoam will foul your plugs and thin your oil out to a useless degree. It's specifically designed to break down deposits in motors both of sludge and carbon. It'll make your motor feel happy too.

[m'ssil80]

thanks thats good to know

[m'ssil80]

oh, i forgot one question will that hurt my car at all or just leave ugly stains every morning? thanks, again

[redtop91]

Nope on both counts. Seafoam is harmless and won't leave any stains or anything. Just make sure you do it outdoors

[m'ssil80]

sorry i wasnt too clear, i meant will the carbon coming out of the exhaust hurt my car/or engine or is it just cuz my new plugs are burning better?

[Zippy69]

Check your tune, you could be rich, or maybe timing, looks like rich fuel to me.Oh yea, gasundhight !!!

[m'ssil80]

ok so its been a couple of weeks since the black stains happened, does anyone know if they are supposed to go away? i searched and found a couple explanations, one being that the piston rings could be bad, but this never happened before i changed my spark plugs, so i dont think that could be it, could it?. i also changed them to one step hotter cuz i dont run so much boost(10psi) so it seems like this shouldnt be happening, should it? the car does run rich, but i never had the problem before.

if anyone can help me out i'd really appreciate it.

[m'ssil80]

bump...anyone have any ideas at all?

[m'ssil80]

bump.............come on anyone? aren't there any experts around? i would really appreciate any help

[janda240sx]

Its just carbon deposits. won't hurt nehting. it will goaway. What octane fuel do you run. You should be using 91-93 or maybe higher if you can get it. Mine does that if I use less then 93 octane.

[m'ssil80]

I only use 93 octane and its just been like 3 weeks and its still doing it.???

[brandonkill]

try doing fuel cleaner if you havent already my friends hard body did this when we dropped sr in and it seemed to fix the prob other than that i would say piston rings would cause this

[Fla240sx]

my theory is thats water........

your car is running rich which is leaving black deposits inside the ehxuast, which turns the water black.......