black smoke

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MasterMan
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black smoke

Postby MasterMan » Sat Jul 27, 2002 4:12 pm

hello i have a 91' 240sx fastback.. all stock except for an air intake.. now its always smelled rich when its running but ive never see it put out black smoke.. my friend was following me one day and said when i gun it from a stand still it shoots out black smoke.. but at all other times its fine.. im wondering if there is a quick fix for this or what do i need to do? it seems to be running fine just kinda smells bad and eats up more gas then it should.. also ive always bought name brand gas (hess, ammico) and its always mid grade or premeum.. same with the lady that owned it b4 me (only 2 ppl have owned it me and her).... anyways thanks for any help you can provide :)


juazam_186
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Postby juazam_186 » Sat Jul 27, 2002 4:12 pm

MasterMan,Have you pulled off the spark plugs and checked them.It will tell you alot about the inner-workings of the piston rings, detonation, etc. ...That should be a start as to troubleshooting your smoking problem. Good Luck.

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PalmerWMD
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Postby PalmerWMD » Sat Jul 27, 2002 4:12 pm

Hmmm,

I'm not ure if this will help as this is coming from a Q45, but cars are cars...

On a Q black smoke, almost always, means bad Mass Airflow sensor, or (more commonly) bad MAF connector.

Fred...:)

Daunttless
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Postby Daunttless » Sat Jul 27, 2002 4:12 pm

Yes, this problem is generally assocated with the MAFs. You may want to check to see that it is functioning properly. If it appears to be in working order, you may wish to make sure the ground is properly connected and jiggle it around a bit to make sure its secure. if that doesn't work, you MAF may be faulty. : )

Nismo_Freak
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Postby Nismo_Freak » Sat Jul 27, 2002 4:12 pm

If you have a re-oilable filter such as a K&N the oil often can gunk up the MAS. Buy a can of carb cleaner and spray the sensor to de-gunk it and this will at least give you a clear primary 02 signal to correct A/F ratios. Pull the plugs and inspect them. Look for electrode damage, oil residues, carbon buildup, and coloration. That will tell you if you are running too rich off the bat. Black smoke could also be oil getting past the rings. Look for an oily residue or an oil fouled plug to tell if your engine has begun to lose compression and has severe blow-by.

YochTown240
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Postby YochTown240 » Sat Jul 27, 2002 4:12 pm

How do u fix blowby??? And how do u regain compression if u are losing it?? New pistons and rings??

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AunVoh
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Postby AunVoh » Sat Jul 27, 2002 4:12 pm

YochTown240 wrote:How do u fix blowby??? And how do u regain compression if u are losing it?? New pistons and rings??
simple short anwser is almost always: Rings.

Nismo_Freak
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Postby Nismo_Freak » Sat Jul 27, 2002 4:12 pm

A full rebuild is the 100% sure way to fix compression but rings often work 80% of the time. If your car has high milage then you may need to get the block re-bored along with your new slug rings.

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MasterMan
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Postby MasterMan » Sat Jul 27, 2002 4:12 pm

ugg rebuilds r a b****.. heh.. well thanks for da info im gonna check some stuff out tonight.. :)

drjohn
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Postby drjohn » Sat Jul 27, 2002 4:12 pm

Don't forget to check the coolant temp sensor and connection and it's possible you may have a slow to respond o2 sensor.

Import Fanatix
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Postby Import Fanatix » Sat Jul 27, 2002 4:12 pm

Why Rebuild? SR20DET Swap Canidate!!!


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