2010 CXS Black Smoke On Start

Pops2010

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Hi All:

I have a 2010 CXS with 23k on it. My grandfather gave it to me recently. He and my grandmother were snowbirds and went to Florida every October - May, so the car has never seen a winter. I haven’t driven it in the snow or salt, but I do start it every other day. When I start it, for about 10-15 seconds after I start it, black smoke, not a lot, but enough to see, come out the tailpipes. After that I get the normal exhaust until it warms up. I’ve taken it on the expressway recently and driven it about 300 miles since I’ve had it. It drives fine. What could be causing this? Should I be concerned?
 

Rich B.

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Also could just be too much fuel enrichment for startup. My Corvette had a 9th fuel injector in the air intake specifically just for that. I know, apples and oranges but if not burning continously black smoke or blue-gray I wouldn't be too worried.

Also a fuel enrichment condition, the catalytic converters will deliver a sulphur dioxide type of odor. Even my '16 LaCrosse sometimes will do this. No concern, converters not going bad. Only MHO diagnosis here, not attempting to outguess any diagnostics.
 

Pops2010

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Thanks for the replies guys! I’m not so worried about it now. With the cold weather we have had here and the ice and snow, I haven’t driven the car in over a week. But I start it every other day.
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Pops2010

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Why not replace the air filter and try some fuel injector cleaner?
I’m going to do that. I have a 13 Acadia with 89k miles on it. Every time I got the oil changed, the new oil was dirty. So I put some cleaner in the gas tank and ever since the oil is clean. I also changed the air filter (that was a chore), and I don’t think that it had been changed since the car was built. It was filthy and clogged up with fuzz, dirt etc.
 

2007LucerneCXL

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No one size fits all here, it's type of smoke and duration combined with vehicle, milage, make, model and year. Toss in owners maintenance or lack of, usage daily or once a month, weather conditions and then it's time to see if it's a problem or its normal operating conditions. With the cold front hitting the Midwest I suspect people will have a whole bunch of "new" things popping up lol.
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Chris Heinen

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Yes, it will be interesting to see what comes of this. There were several models listed in the OEMDTC bulletin and the thing in common between them was that they were direct fuel injection engines compensating for cold start emissions. Looking forward to the OP's changes/results.
 

Mad*Max

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I never would have thought that black smoke is normal on a gas vehicle.
 

Pops2010

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If I'm reading this OEMDTC write-up correctly, GM says black smoke on cold start is normal. There are a few caveats/qualifiers in their bulletin, but thought I'd pass it along. I had not heard of such a thing before...

Black Smoke and Rough Idle On Cold Start - 2008-2016 Buick Cadillac Chevrolet GMC Saturn.

I had always assumed that smoke (of any kind) was a no-no, but maybe not???
It happens for around 10 seconds. I counted each morning when I started it when we had the “polar vortex”. So that falls in line with the information in the bulletin that you posted.

No one size fits all here, it's type of smoke and duration combined with vehicle, milage, make, model and year. Toss in owners maintenance or lack of, usage daily or once a month, weather conditions and then it's time to see if it's a problem or its normal operating conditions. With the cold front hitting the Midwest I suspect people will have a whole bunch of "new" things popping up lol.
I changed the air filter, it looked fairly clean. But the car only has 23,200 miles on it. It’s had oil changes every 6 months like clockwork. Since it only got driven about 2k miles a year, my grandfather changed the oil in May when they got back from Florida and in November before they left for Florida. Even though the car sat from Nov to May he still changed the oil in May.

I never would have thought that black smoke is normal on a gas vehicle.
Me either. That’s why I was so concerned.
 
Last edited:

dbris

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Black smoke indicates an over rich mixture which I would consider normal on a cold start.
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NormT

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Probably just carbon build up. You didnt say what engine but it may just need to get good and hot on a long ride.
 

Pops2010

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It was finally half way decent out today to take it out. I have never looked under the hood since I have gotten the car. So I checked the oil (not low and still clean). I did buy a new air filter, which I’ll put in tomorrow. The battery is not even a year old too.

The car was NEVER driven on the highway. My guess is the highest it got up in MPH was 55ish. So when I took it out today, I took it on the freeway and punched it a couple of times and got up to 80ish. I’m going to have the oil changed, tires balanced and rotated (slight vibration around 65-70) and it needs an alignment. So I’ll mention it too when I go there. But honestly, I’m not too impressed with the Buick dealer by my house. But we don’t live in a big area.
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Pops2010

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(@Pops2010) Just wondering if the problem went away after you took it on the freeway. Or is it still smoking for 10 seconds on cold start?
I’ve taken it out one more time when it was nice. It is still doing the black smoke for 8-10 seconds upon a cold start. I bought a K&N air filter, but I can’t get the top off to replace it. So when it goes in for an oil change, I’ll have that replaced. But as of now, it’s about 8-10 seconds after start.
 

Pops2010

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So, I had the following done.

1) I put fuel injector cleaner in a full tank of gas and drove it about 300 miles on the highway.
2) Had the K&N air filter installed.
3) Had the oil changed.
4) Had the tires rotated.
5) Had tires balanced.
6) Had an alignment completed.
7) Have switched to premium (91 around here) on the last 3 tank fill ups.

I can tell a difference in the performance. But I’m still getting the black smoke on start, especially in the cold. I tried to upload a video from this morning, but it didn’t work.
 

2007LucerneCXL

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There are a few newer GM'S that have the same type of black smoke on start, a few TSB on it as it's considered normal, but it's because the catalytic converter hasn't reached operating temperature for those first few minutes. May be a similar problem and considering the type of driving it could be that simple.
 
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