legacycentral bbs

I have an intermittent problem with my '94 Sport Sedan. Sometimes, while accelerating, it will dog and blow a puff of black smoke out the exhaust. I'm thinking that maybe it's loading up on gas at this moment in time. Due to the very intermittent nature of the problem, I don't want to take it in for service. I've seen times in the past when I've spent money on "best guesses" only to face the same problem again with less money in my checkbook. I was directed here from another forum. Seems this is where the folks eat, breathe and sleep Legacy. I couldn't locate a search feature to see if this topic has already been covered. So how about it, any good guesses for things that I can check or do myself? (No, I wouldn't object to just changing out some less expensive parts based on deductive reasoning!) Thanks in advance for any thoughts on this.

My first ideas would be a misfire or something else that would cause a sudden rich condition ie intermittant boost leak or sticking turbo bearings...

Can turbo bearings even stick?

I donno.

Welcome to Legacy Central!

Does this only occure during WOT accelaration or does it occure under partial throttle accelaration too? I would check your plugs and plug wires. Do you know how old they are? When was the fuel filter last replaced? Do you notice if it happens during similar atmospheric conditions or is it completely random? Besides this, is anything else wrong with the car?

Oh, I forgot to ask, do you have any mods?

This condition will occur during any type of acceleration. I have changed the plugs and wires with no change. (I did notice that only one of the plugs had some fouling, so I thought maybe that was it.) I didn't do the fuel filter, thinking that this wouldn't give me the black smoke.) As far as conditons, it may be less frequent during winter conditions. And no, I haven't done any mods, yet. (Of course, I didn't know about this site though!)

OK lets just get a few things straight here, for everyone's benefit --

white smoke = burning oil?
black smoke = excess gas in exhaust/rich condition?

Are we all in agreement on this, or am I way off my rocker?

I thought blue was oil, and white was coolant?

Hardy's got it.

White = coolant or cleaned deposits and crap
Black = excess fuel
Blue = oil

Steve

evolutionmovement wrote:Hardy's got it.

White = coolant or cleaned deposits and crap
Black = excess fuel
Blue = oil

Steve

Yup.....


If only one plug is fouled, could be a sticky injector, a wire, or mechanical failure in that cylinder.

Betya he has a leak somewhere in his intake/vaccum system

totech wrote:Betya he has a leak somewhere in his intake/vaccum system

But would that show up intermittently? Let me add that when this problem crops up, it's not necessarily at the beginning of accelerating - it might be right in the middle of an acceleration ramp. Also, this car has always started instantaneously when you hit the key, but once in a while, it doesn't. I assume at the times that it doesn't (which is rare) that this is a manifestation of the same symptom.