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Motor running rich

08-09-2004, 07:35 PM
i just got done putting a d15b into my 93 civic dx and i have a problem with the motor running rich(black smoke comes out the pipe), i changed the plugs,wires,rotor,oxygen sensor,i got all the vac lines and sensors hooked up but still throws black smoke.The check engine light stays on. If anyone has some ideas for me to try let me know, Thanks

08-09-2004, 09:43 PM
hmm, not sure, but when my friend's harley was fouling spark plugs a lot he retimed it (it was off quite a bit) and it made a difference. i would check that. do you know if your rings/seals are good?

08-09-2004, 09:59 PM
Its burning rich, not burning oil

08-09-2004, 10:01 PM
i may be way off on this but make sure your spark plugs are gaped correctly

08-09-2004, 10:09 PM
yeah, your right, your wayy off

08-09-2004, 10:12 PM
well i wont claim to know it all

thats why im on this forum


08-10-2004, 10:01 AM
running rich, d15, redid all the sensors and lines, plugs are good....hmmmmmm....did you get all the wiring done correctly? it would seem to me that if you checked all those things (and they are done correctly) then some computer issue would be the problem. or it's a normal amount of black smoke.

when are you seeing smoke? all the time, early in the rpm range, late in the rpm range, anything over idle?

you say you checked th O2 sensor, but all the others are just "hooked up" have you checked the PCV sensor? (there should be one on the 93 DX), not to doubt you, but if I had a nickle for everytime I just didn't think to check something simple like that...

are all your seals and clamps sitting correctly?

I would need some more detail on what you've done in there, but baring that, I would say to check the timing, and possibly zip over to some shop, have them hook up to your ECU and get a diagnostic.

08-10-2004, 10:04 AM
or, after reading your mods list, perhaps a lack of CAT on your exhause system from the straight pipe set up is the reason for the added puffs

08-10-2004, 10:16 AM
black smoke = too much fuel
white smoke = oil consumption
spark plugs could have been fouled but they have been replaced
what ecu are you running?

i am assuming that by d15b you mean the jdm sohc vtec motor? if this is the case i would look for a wiring problem, even if you think you did it right

08-10-2004, 10:56 AM
the black smoke shows through the whole rpm range, im running a d15b sohc vtec, with a p28 ecu

08-10-2004, 11:22 AM
does the engine run smoothly other than the black smoke? have you taken out the plugs you put in and looked at them? if one is all dirty and the rest arent it is possible that you might have a stuck fuel injector

08-10-2004, 12:22 PM
when it throws black out of the pipe it sounds like it has a miss in the motor,when i pull the plugs they are all coated with black (carbon), not oil or anything

08-10-2004, 02:10 PM

stuck injector, air filter, engine management (ecu issues), fuel pump, wrong plugs (NKG are OEM), could also be cause by misfiring, ie: timing.

make sure you have the right plugs in there, if you went too low a heat range, that would happen.

air filter clean?

and, this is for me, is a P28 the right ECU for that d15? I thought the P28 was for the d16y8? I could be wrong...

how's the throttle body cable? that could need tightened, maybe not be opening enough to let enough air in. wealth of possibilities....

Try all the stuff you can do in your driveway, if no go, diagnostic cause it may be something you can't see - stuck injector, fuel pump, etc. the diagnostic will read where the bad mixture is coming from.

08-11-2004, 12:42 AM
a p28 ecu is from a 5th gen( 92-95) civic ex with the d16z6. i personally think its one of your vac lines, and it also might have to do with the fact that you dont have vtec hooked up yet. all you'd have to do is leave one sensor un plugged and it'd end up being the one you needed to make it run right. maybe you should have another person besides yourself check your wiring, and see if they can find anything.
why are you even wasting your time with that motor? why dont you just throw an h22 in, or is that coming this winter ? :loser:

08-13-2004, 10:48 AM
found out the ecu was junk, the kid that had it before me tryed to chip it by himself with a soldier gun.what a fool :lol2:

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