Black smoke on hard accell? (1 Viewer)

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Searched, found lots of white and blue smoke threads but no black smoke threads.

Shortly after leaving work tonight as I was getting on the freeway I got stuck behind a semi doing ~30MPH, everybody was whipping around the two of us and took a wile to finally find a hole to go around, had to floor it to not get rear ended, tranny downshifted and R's went up to 4-5K or so, looked up at the truck bearing down on me and noticed a thick cloud of smoke coming out of the back of my 80 in the glare of his headlights. It looked like black smoke but not 100% sure in the dark. Power output was good and seamed smooth. As soon as I let off it up shifted R's came down and the smoke immediately stopped.

Black smoke should be partially burnt fuel, I know the computer will go slightly rich at higher power setting but I would not think that it would go so rich as to make a cloud of smoke?

Engine was in the later stages of warm up and should have been in closed loop.

I am going to try to reproduce this in the day time and see what i get.

Hopefully this was not white smoke, about 2 months ago I did have to put some coolant in the overflow but the coolant is close to 2 years old and the level had not been adjusted since, it has not dropped noticeably since.

Any idea's / thoughts
 

powderpig

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If it is black then you are correct about unburnt fuel. If you have some software on a computer you may be able see it in the O2 reading. It could be a dribbling injector. The other explination if it is cold there is heat vapor changing the wave lenght of the light to give like a shadow or such gremlin type of look. later robbie
 
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Robbie

is black somke something you have seen in 1FZ's before? if not I think that takes out "typical" as an explanation.

I have been wanting to do software OBDII for a wile, never have had an extra $100-$200 for it, may have to move this up in priority.

did not really look like heat waves/mirrage but could be, nigh time in a mirror staring at headlight glare is not a great time to view smoke.

could a injector leak or dribble in a way that only shows at higher loads? my milage has been OK, 14.5 to 15.5 in the summer, 14.0 to 15.0 in this cooler weather, until now only seams to run rich before warm up in cold weather.
 
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Black smoke == engine's running rich

Possible cause could be a bad 02 sensor, a clogged FI(s), AFM (rare) to name a few...
 
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Have somebody drive your truck and you follow in another rig. Could have been as simple as the accumulated condensation in your exhaust pipes getting vaporized and blasted out into the cold night. Do that on my block tonight and you'll put out a house size cloud of water vapor.

Use cell phones to have the driver do various combinations of acceleration and deceleration.

DougM
 

powderpig

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No black smoke is not typical (On the 1fz). but anything is possiable, as you open the injector longer (WOT) and dribble becomes a stream of fuel instead of atomized fuel making it harder to use in the engine. I have seen a coulpe of SC trucks with black smoke under hard acceleration and it was only once in a while type of thing. As doug pointed out, O2 sensers and Injectors are the biggest culprits. Injectors in both cases took care of the problem. Not to say this is your problem, good software with graphing capabilities will help alot to find the culprit. good luck robbie
 

Uncle Ben

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How much soot is in your tailpipe? Have you pulled a plug and checked the color of the insulator? A black puff on WOT can happen and is not nessesarily bad. Better to be slightly rich on WOT than lean! What was ambiant temperature? Cooler air charge will also tell the ECU to enrichen the circuit. I suspect Robbie is on it and you have a injector or two not fogging properly. Do a couple tanks with injector cleaner through it and see if it gets better. 15mpg seems like it's in pretty good tune to me!
 
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If I "romp" on the pedal when trying to get on the interstate around here I can make a puff of black smoke. I think its unburned fuel in the exhaust. Samething happens to diesels, its running rich which as uncle ben said is better than lean esp at WOT. If you step on a diesel it will dump black smoke which is essentially unburned fuel buring off in the exhaust. The severity may have something to do with injectors/senors but I surely wouldn't call it a problem. I'd rather run rich than lean any day of the week if I need to step on the peddle.
 

Vlad

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Critter said:
If I "romp" on the pedal when trying to get on the interstate around here I can make a puff of black smoke. I think its unburned fuel in the exhaust. Samething happens to diesels, its running rich which as uncle ben said is better than lean esp at WOT. If you step on a diesel it will dump black smoke which is essentially unburned fuel buring off in the exhaust. The severity may have something to do with injectors/senors but I surely wouldn't call it a problem. I'd rather run rich than lean any day of the week if I need to step on the peddle.
Trust me, if your cruiser looks like my diesel when I stomp on the skinny pedal...you have problems :)

I leave a con-trail for about 400 yards if i get my big diesel going from stop to go in a hurry.
 
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Doug I get lot of water vapor this time of year, I am used to that, usually spot it because it dissipates quickly, you can watch it disappear, this stuff sticks around, The temps were nice that night, maybe 50's or 60's

Tried to repeat it again today with limited success, could not get the R's up wile it was warming up, tranny did not seam to want to let the engine get up too high, once up to temperature I could only get it to smoke once, idling rolling at 20mph floored it got high R’s and was rewarded with a puff of dark grey/black smoke. Did not seam as bad as last night. Seams to only follow high load/ high RPM and not necessarily throttle position.

I changed the plugs about 13K ago, they had about 30k on them besides a corona stain they looked very good.

Just checked the tail pipe and looks like dry black soot at the outlet, looking in with a flash light it gets thinner almost immediately as you go foreword and changes to an ash white right before the goes around the bend foreword of the resonator. Is it that much hotter there to form ash and not soot?

Looks like I need to get OBDII software.

Thanks guys
 
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RT -

As Robbie noted, the O2 sensors and injectors are potential problem areas, though I'm skeptical about the O2 sensors.

But there are a couple more easier-to-check items too: when you go into open-loop (by stoping on the gas), the ECU will change the injector pulse based on the ECU's map and the TPS and MAF sensor inputs (the O2 sensor is not used in open-loop; I have not looked this up for the LC, but all other cars/trucks I've worked on do this). If either the MAF or TPS is not providing the correct signal, you would get the wrong injector pulse and could be way richer than needed. I'd check the TPS to be sure it's set right, and clean the MAF, then see if you still get smoke. In any case, that's easier than replacing your injectors:D
 
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DanKunz said:
Trust me, if your cruiser looks like my diesel when I stomp on the skinny pedal...you have problems :)

I leave a con-trail for about 400 yards if i get my big diesel going from stop to go in a hurry.
... and I can't get our diesel to smoke that much though I have seen one smoke like crazy climbing a hill with a load on (loaded cattle trailer). For some reason it seems like the last generation cummins motors smoke more...

Diesels can get marketed gains in power that a gaser can't (hp and torque) by simply dumping more fuel into the cylinders (thats why people chip them).
 

Uncle Ben

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Critter <snip> Diesels can get marketed gains in power that a gaser can't (hp and torque) by simply dumping more fuel into the cylinders (thats why people chip them).[/QUOTE said:
Very true but power equals heat. A lot of folks who chip only go part way. On a diesel it's is crazy not to monitor exhaust gas temps (EGT) especially if you have modified it and are dumping more dead dinosaurs through it. If a diesel is pumping heavy black smoke while pulling load the exhaust manifold is also glowing cherry red!
 
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My 92 does the same thing. I know it's a different engine, but what you are discribing is the same. At high r.p.m.'s (usually when passing) I will get black exhaust out the tail pipe. I don't usually do it enough to be a problem so, I've never really looked into it. good luck, chuck
 
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Rock Hog said:
My 92 does the same thing. I know it's a different engine, but what you are discribing is the same. At high r.p.m.'s (usually when passing) I will get black exhaust out the tail pipe. I don't usually do it enough to be a problem so, I've never really looked into it. good luck, chuck

Mine too. Me too.


Kalawang
 

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