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black smoke and lean fuel

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Old 11-03-2004, 07:27 AM
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black smoke and lean fuel

i have been getting some black smoke coming out and it smells like gas. i am also getting the code 0115 which means the fuel is coming in lean to the engine. the o2 sensors are all fine and were changed within the past five thousand miles. i am pretty sure the maf sensor is fine too because i dont have the code 0102 and am not suffering from maf problems. i have the stock intake and am pretty sure there are no air leaks. so, that one 0115 code is stopping me from getting my emissions testing done. anyone have any idea why some of the gas does not seem to be burning while i am getting lean fuel into the engine. also, sparks were changed not more than ten thousand miles ago with ngks.
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Old 11-03-2004, 09:29 AM
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that seems odd that its running lean but burning out black smoke.

Maybe EGR need cleaning or PCV valve, or maybe injectors.

just spitting out potential sources of the problem.
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Old 11-04-2004, 07:01 AM
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any other ideas?!
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Old 11-04-2004, 07:05 AM
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Black smoke = rich fuel mixture(usually)

Are there any other codes?
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Old 11-04-2004, 09:22 AM
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only 0115 which means there is lean fuel... it doesnt make sense
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Old 11-04-2004, 09:54 AM
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Lean fuel? You mean lean air/fuel mixture right? Meaning you're getting too much air and not enough fuel, it should be a 10 to 1 air to fuel mixture. You might have an air leak in the intake somewhere, injectors or fuel pump maybe messed up, fuel filter.
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Old 11-04-2004, 10:16 AM
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I am willing to bet its your PCV valve...I know people with the exact same problems....all they needed to do was change the PCV valve....its cheap, I would do that first
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Old 11-04-2004, 10:33 AM
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You may have an exhaust leak at or near the O2 sensors.

Fresh air coming into the exhaust is causing the O2 sensors to measure a lean condition, which the ecu tries to correct for by adding fuel. Apparently the leak is so bad that the ecu cannot compensate enough, so you get the CEL. All the additional fuel is making your engine run very rich.
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Old 11-04-2004, 10:36 AM
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Originally Posted by DAVE Sz
Lean fuel? You mean lean air/fuel mixture right? Meaning you're getting too much air and not enough fuel, it should be a 10 to 1 air to fuel mixture. You might have an air leak in the intake somewhere, injectors or fuel pump maybe messed up, fuel filter.
10 to 1 is way too rich, even for boosted engines. Stoichiometric is 14.7:1, and that's where you should be during idling and cruising, and light acceleration. AFR during WOT acceleration shouldn't be lower than 12.5:1 for a naturally aspirated engine.
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Old 11-04-2004, 11:04 AM
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You can't get black smoke from a lean fuel mixture, esp. if it is smelling like gasoline. My friend has a 98 2-door Accord V-6 and was having the same problems. He changed the oxygen sensor to no avail. I think that he is having Cat problems too. But fouled plugs are more than likely the culprit. Oh and 10:1 will look like diesel exhaust coming out of your tailpipe. Or, if boosted, make flames shoot out of your tailpipe after letting off WOT (which looks cool). Or just backfire like my old Bronco, which was not particularly cool.
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Old 11-04-2004, 11:18 AM
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stephen... that seems logical... ill check my warpspeed y to see if there is a leak...
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Old 11-04-2004, 11:33 AM
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Originally Posted by Stephen Max
10 to 1 is way too rich, even for boosted engines. Stoichiometric is 14.7:1, and that's where you should be during idling and cruising, and light acceleration. AFR during WOT acceleration shouldn't be lower than 12.5:1 for a naturally aspirated engine.
Sorry about that, for some reason I remember reading that the amount of fuel going to the engine is a 10th of the amount of air. I didn't even remember to realize that stoich is 14.7:1.
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