Black soot above exhaust - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

gschroeder78 · 06-26-2002, 09:35 AM

Hey guys,
I've got the N1 Dual on my '89 240sx and since then, I've been getting this black soot deposit all over the back of my car. I'm sure this is burnt fuel so how can I stop my car from running so rich? It seems to backfire moderatly, I've changed the spark plugs, O2 sensor, fuel filter and oil. No luck. Can someone please tell me how to fix this? I can't paint it until I stop this from happening.

Thanks

gschroeder78 · 06-27-2002, 07:38 AM

Could I possibly need to upgrade the computer? I've heard that that the cpu is the only way to adjust fuel mixture but I've also heard that if you upgrade it, your car needs to be running good. Is running rich considered not running good?

Hopefuly someone knows about this.
Thanks

chickenmanq · 06-27-2002, 12:16 PM

You kept the catalytic with that exhaust, right?  Is it new, is it blow out?  If that was gutted, or non existant, it would backfire and throw excess soot out the back due to low backpressure playing with the O2 sensor.

gschroeder78 · 06-27-2002, 12:19 PM

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (chickenmanq @ June 27 2002,12:16)</td></tr><tr><td id="QUOTE">You kept the catalytic with that exhaust, right? Is it new, is it blow out? If that was gutted, or non existant, it would backfire and throw excess soot out the back due to low backpressure playing with the O2 sensor.</td></tr></table><span id='postcolor'>
I kept the original cat. The smoking started with the new exhaust and it did backfire moderatly even with the stock exhaust. Could the cat be clogged?

uiuc240 · 06-27-2002, 03:56 PM

how long have you had the exhaust? some of that smoke is from the lubricant that they use for the mandrel bends. if it's lasting for weeks, though, you could probably use a tune-up and an ecu reset. check your o2 sensor too.

EDIT:  reread your post and realized that you already did the tuneup.  my 89 was sooty like that with the duals and my KA...it's not with the SR though.  i think part of that is just that the KA24E runs richer than the DE.  but that could be in my imagination too.  i just know that i got lame mileage the whole time i had it.

Eric

gschroeder78 · 07-01-2002, 08:55 AM

bump... still looking for more ideas, thanks.

*SaintlyCharBoy* · 07-01-2002, 04:44 PM

the only fix that i've ever seen or heard of is a small polished stainless plate above the tip(s), basically when it gets funky/nasty, you can just wipe it off  <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>

tnord · 07-01-2002, 06:04 PM

if it backfired when you had the stock exhaust, there is most definitely something non exhaust related with your car. well at least, nothing after the cat. i've heard the N1 dual backfires a bit naturally, but if it was doing it with the stock system on there.......well, i'd have it looked at.

06-26-2002, 09:35 AM	#1
gschroeder78 Zilvia Junkie Join Date: Nov 2001 Location: Westminster, CO Age: 46 Posts: 507 Trader Rating: (0) Feedback Score: 0 reviews	Hey guys, I've got the N1 Dual on my '89 240sx and since then, I've been getting this black soot deposit all over the back of my car. I'm sure this is burnt fuel so how can I stop my car from running so rich? It seems to backfire moderatly, I've changed the spark plugs, O2 sensor, fuel filter and oil. No luck. Can someone please tell me how to fix this? I can't paint it until I stop this from happening. Thanks __________________ 1989 240SX Coupe -Eibach Prokit Springs -KYB AGX Struts -Apex-i N1 Dual Exhaust Westminster, CO

06-27-2002, 07:38 AM	#2
gschroeder78 Zilvia Junkie Join Date: Nov 2001 Location: Westminster, CO Age: 46 Posts: 507 Trader Rating: (0) Feedback Score: 0 reviews	Could I possibly need to upgrade the computer? I've heard that that the cpu is the only way to adjust fuel mixture but I've also heard that if you upgrade it, your car needs to be running good. Is running rich considered not running good? Hopefuly someone knows about this. Thanks __________________ 1989 240SX Coupe -Eibach Prokit Springs -KYB AGX Struts -Apex-i N1 Dual Exhaust Westminster, CO

06-27-2002, 12:16 PM	#3
chickenmanq Zilvia FREAK! Join Date: Nov 2001 Posts: 1,000 Trader Rating: (0) Feedback Score: 0 reviews	You kept the catalytic with that exhaust, right?  Is it new, is it blow out?  If that was gutted, or non existant, it would backfire and throw excess soot out the back due to low backpressure playing with the O2 sensor. __________________ <img src=http://dana.ucc.nau.edu/~mka/av620b.jpg> -"Yeah? Well Your Mom Drives A Civic Type R!" 81 Honda Accord Hatchback. EK1 engine. 78 Datsun 620. L20B engine. I'll try to have pics soon. Check the website for more. http://dana.ucc.nau.edu/~mka

06-27-2002, 12:19 PM	#4
gschroeder78 Zilvia Junkie Join Date: Nov 2001 Location: Westminster, CO Age: 46 Posts: 507 Trader Rating: (0) Feedback Score: 0 reviews	</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (chickenmanq @ June 27 2002,12:16)</td></tr><tr><td id="QUOTE">You kept the catalytic with that exhaust, right? Is it new, is it blow out? If that was gutted, or non existant, it would backfire and throw excess soot out the back due to low backpressure playing with the O2 sensor.</td></tr></table><span id='postcolor'> I kept the original cat. The smoking started with the new exhaust and it did backfire moderatly even with the stock exhaust. Could the cat be clogged? __________________ 1989 240SX Coupe -Eibach Prokit Springs -KYB AGX Struts -Apex-i N1 Dual Exhaust Westminster, CO

06-27-2002, 03:56 PM	#5
uiuc240 Nissanaholic! Join Date: Apr 2002 Location: Naperville, IL Age: 46 Posts: 2,093 Trader Rating: (0) Feedback Score: 0 reviews	how long have you had the exhaust? some of that smoke is from the lubricant that they use for the mandrel bends. if it's lasting for weeks, though, you could probably use a tune-up and an ecu reset. check your o2 sensor too. EDIT:  reread your post and realized that you already did the tuneup.  my 89 was sooty like that with the duals and my KA...it's not with the SR though.  i think part of that is just that the KA24E runs richer than the DE.  but that could be in my imagination too.  i just know that i got lame mileage the whole time i had it. Eric __________________ 2002 Mazda Protege5 1989 S13 w/SR20DET (sold)

07-01-2002, 08:55 AM	#6
gschroeder78 Zilvia Junkie Join Date: Nov 2001 Location: Westminster, CO Age: 46 Posts: 507 Trader Rating: (0) Feedback Score: 0 reviews	bump... still looking for more ideas, thanks. __________________ 1989 240SX Coupe -Eibach Prokit Springs -KYB AGX Struts -Apex-i N1 Dual Exhaust Westminster, CO

07-01-2002, 04:44 PM	#7
SaintlyCharBoy Premium Member Join Date: Jan 2002 Location: Bow, NH Age: 43 Posts: 849 Trader Rating: (1) Feedback Score: 1 reviews	the only fix that i've ever seen or heard of is a small polished stainless plate above the tip(s), basically when it gets funky/nasty, you can just wipe it off  <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'> __________________ 92 vert - KADE + VH41 + GM MA5 = too many parts in the garage 95 base - retired

07-01-2002, 06:04 PM	#8
tnord Nissanaholic! Join Date: Dec 2001 Posts: 1,975 Trader Rating: (0) Feedback Score: 0 reviews	if it backfired when you had the stock exhaust, there is most definitely something non exhaust related with your car. well at least, nothing after the cat. i've heard the N1 dual backfires a bit naturally, but if it was doing it with the stock system on there.......well, i'd have it looked at.