punkindrublic

my buddy was driving behind me tonight and said there was black smoke coming from my tail pipe. but only when i shift gears. like when i let off the gas and when i get back on the throttle no smoke. he said it wasn't blue at all so does that mean its not oil for sure? cause that would suck. but anyways any ideas on what it could be?

Jugglez

First things first, pull your plugs and check them for discolouration or damage.

Here's a reference guide:

http://jdmfan.com/index.php?information=read_sparkplugs

punkindrublic

alrite i just pulled them, they are all normal. just a little brown but thats ok. so i dont know. there just the regular ngk ones from crappy and have been on maybe 5000 km tops. new wires were put on at the same time. the motor is somewhat old with a little over 230 kms.

this smoke is only at full throtle when i shift. and when i get next gear it goes away. hopefully the motor isn't going to die anytime soon. can't swap till next spring

SiR-Racer

i see the same black smoke from my friends lude and his car is relatively new ('97). i just assumed that this was normal...

punkindrublic

hmmm well my car is definately not new. but if this was something normal that would be very good.

Jugglez

Are you getting any popping sounds?

You had the wires and plugs changed recently, did you change the cap and rotor as well? These are fairly cheap maintenance items. Around $30 new.

Hate to say it but it could be a bad valve or 2... could be.

punkindrublic

ummm well i had the luzary of having my distributor seize not to long ago so its all new. as for backfiring. it does. but only when as i'm decelerating and have my foot ever so lightly on the gas. my exhust is new also with one resonator (dont know if thats normal or not). but other than the decelerating thing it doesn't backfire.

bent valves aren't good news. actually the same guy who noticed my smokey business has an 89 nissan pular with the twin cam motor. he bought the car as is for well under what its worth. but it needed a lot of head work done. long story short he spend like $2400 to safety it. and i believe like 1500 was head work. it had bent valves and the whole nine yards. the twin cam pulsar engine is apparently quite rare here and thats why he had to fix it rather than replace it. but one positive is that i could probably get a new z6 motor for dirt cheap.

Jugglez

$1500 in head work?? That must have been one really messed up head.

punkindrublic

well roughly that. it ran on 2 cylinders when it was purchased. it was in rough shape. as far as i know basically it got all new valves, springs and i think one of the cams. so its mint now. those pulsars are actually suprizingly quick cars. plus the ghetto pop up head lights and t tops. its unique style makes it a hit with the ladies also.

redfox

When shifting under full throttle, for 1 short period of time, the injectors does not respond as quickly to the throttle plate position. Hence more fuel is let into the cylinders than air. So you run really rich, but just for a second. A stock car doesn't do this at all because even when it runs rich it's still not rich enough to see the smoke, but once you've added I/H/E or whatever else, you've affected the fuel map and the amount of air getting into the car for one reason or another. Sometimes to causes a situation like you've described. I know many cars that do this (2000 SiRs with CAM gears plus other mods, my car, etc.). No worries. It's quite normal.

BB1-4WS

Poor guy! He could have swapped in an engine from the Nissan Sunny, or Pulsar GTI-R with some of that money.

punkindrublic

ya i know he could have done a lot of things.

rbius

hrm.. same situation i'm in.. just swapped a z6 into my ride a few months ago.
how's your oil holding out? I'm flying through the stuff like I have a 2-stroke engine...
let me know, and lets see what we can figure out...

punkindrublic

ya its all about the d16z6..... the d is for domination.

mine has like 234 000 kms. i've had it since about 180 and i've raced it since the day i got it. but as far as i know it doesn't burn oil. i dont have much syncro action in first through third. but the gears aren't chipped yet. and the motor itself is still mint. its a testiment to how tough honda built even the dominant d series motors

rbius

hrm.. not sure then for your situation, cuz I'm goin through oil like crazy.. 10:1 ratio almost... fill the tank, fill the oil ARG! and to think i paid good coin to get this swapped in