Hello guys,

Im new into this site, hope i can get an answer to my question in here
black smoke is coming out of my exhust when shifting at high RPM, i know that this is due to running rich!! but i was wondering what is causing this,and how can i solve this problem.
BTW my fuel consumption is fine, about 23-24 mpg

 

Prob burning oil. Do a compression and leakdown test

 

man, but burning oil will not make a black smoke, it would be somehow blue

 

Do you have ANY modifications to your car at all?

 

No man, its still stock..just a sport muffler.
A K&N short ram will be recieved within 1 week..hope this will not make things worse!

N.B:Spark plugs and wires recently changed.

 

Did you gap the plugs correctly? What plugs and wires did you use?

Also, check your exhaust for leaks, mainly near the O2 sensors.

 

yup i used the correct spark plugs and wires, i dont think its related to that beacuse i remeber a freind of mine told me that he saw a little black somke, and that was even before changing the spark plugs and wires.
umm...i never checked for any leaks.
What i dont have any idea about is the possible reasons behind this smoke

 

"Correct" doesn't tell us anything.

You know the smoke is black. That tells us it's running rich. We can start with the simple, cheap things and go from there. Some factory motors are tuned to run rich at higher RPMs to prevent detonation - if it only happens when you're bouncing the tach, that's possibly the reason for it. Easiest way to fix it? Stop bouncing the tach. Your motor doesn't make power that high, anyway.

 

ummm, its almost at 7500 RPM..its a b16a2 engine.. it should be normal to have the vtec screaming till that rpm.
anyway ill discard this issue as long as its happening only at high rpms.
thanks for ur intrest

 

Checking the exhaust for cracks, especially around the O2 sensors, still wouldn't hurt. Also, leakdown and blowby tests would probably be a good idea, even if they're just for preventative maintenance reasons. They're all free things you can do, just to make sure your motor is still healthy. My car gets pressure tested every oil change.

 

What car and set up?
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You MUST provide all pertinent information about your car and engine. Failure to do so may result in thread closure.




.

 

Could be your 02 sensor

 

Just to confirm, you do still have the stock cat converter installed, correct?

 

Compression and Leakdown tests!!! Happens at every shift? It's internal. Probably rings! No tune up or O2 sensor is going to fix that.

 

I tried to say its oil. But op believes its fuel

 

I'm with you because it wouldn't matter either way if he's puffing smoke.

 

Especially when he says its at high rpms

 

Now it seems really confusing between Fuel or oil !!
my engine's oil slightly drop between every change, but this is sue to a small leak from the distributor o ring which has been since 4 months.
So i cant say this missing oil is causing the black smoke.

It is a civic si 00 almost stock (only sport muffler), and recently changed sprak plugs (correct gap) and wires.
Cat converter still there.

sooo

 

Oil, 99% if you were loosing any measurable amount of oil from the dist. o-ring it would be everywhere, you're burning oil man and running it hard will only make it worse.

 

 

Thanks guys,
im gonna do a comperssion and leak donw lest soon.

BTW do u think the oil im using has to do with this?
I use TOTAL 5w30 synthetic, the engine has almost 100K miles.

 

Just do the damn tests. Worry about one thing at ta time.

 

On the subject of full synthetic, if it hasn't run synthetic all 100k it's not a good idea to run it. Synthetic doesn't have the detergents in it that conventional oil does because it doesn't leave deposits like conventional does. Not a good idea to use synthetic unless it has had it since mile 1.

 

Completely false. Ask me how I know.

 

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