Oil change leads to black exhaust

[Jinx]

I need opinions on what may have caused this.

My mother had her '05 V6 in at the dealership for a simple oil change. The car has been running perfectly up until this day.

The dealership conned her into believing she needed an injector cleaning too. So now the car is running extremely rough and the exhaust is putting out enough black smoke to actually turn the rear bumper black by the exhaust tip. The only other thing they touched (as far as I know) is they replaced the airfilter.

She did take it back in yesterday, and they turned off the CEL. I say "off" because it was not reset, due to the fact that the light no longer comes on temporarily at engine startup. She is planning on taking it back in tomorrow on her day off.

Any suggestions as to what has happened?

 

[black2010]

May want to ask them used seafoam to clean the injectors and carbon build up. That stuff works pretty good but will make it look like your car is on fire from the back.

Other than that I'm stumped.

 

[Jinx]

Not sure why they needed to clean the injectors in the first place. With todays cleaner engines and cleaner fuels, I would not expect to have to do a FI cleaning until 75,000 + miles. She barely has 50k on it.

 

[CA Lightfoot]

1. Check the dipstick. Oil should be clean and proper level. Might be overfilled, causing oil blow-by into the exhaust.

2. Look at hoses & connectors on or near the air filter housing. If something is loose or disconnected or not properly seated, it might cause the engine to run rough.

3. A loose/disconnected/damaged spark plug wire might explain explain the black smoke and rough running. But I can't imagine how this might've happen.

4. Injector cleaning? What did they do? Probably just added some injector cleaning fluid to the gas tank, which shouldn't cause any problems.

5. Give the dealer one more routine chance to make things right -- no need to yell (yet) -- including a properly-functioning CEL.

Probably a grunt did the original service and messed-up something.

 

[d90212]

lets not mix up smoke here:
black - rich unburned fuel/hydrocarbon
blue - oil....lingers in the air for a very long time...
white ish / sweet sorta smell- water/coolant..usually dissipates right after the tail pipe...

so what is it?

 

[Jinx]

Black soot on rear bumper around exhaust.

I have a feeling the car is running rich, but I don't understand as to why. The only thing I can think of is the computer has to relearn the fuel curves after the dealership "cleaned" the injectors. The MAF may be disconnected or damaged, because they changed the airfilter as well, which may cause a rich condition.

I just don't see how cleaning the injectors could cause a rich condition to the point that it leaves a heavy soot layer on the bumper.

 

[Jinx]

...

4. Injector cleaning? What did they do? Probably just added some injector cleaning fluid to the gas tank, which shouldn't cause any problems.

5. Give the dealer one more routine chance to make things right -- no need to yell (yet) -- including a properly-functioning CEL.

Probably a grunt did the original service and messed-up something.

Not sure what they did to the injectors, but they charged over $50 . Mom is a fair woman, and will give them all the opportunity to make things right. I just wish I lived closer so I could take a look at it myself. Probably do the oil changes for her as well.

 

[Jinx]

...I have a feeling the car is running rich, but I don't understand as to why. The only thing I can think of is the computer has to relearn the fuel curves...

BINGO!!!

After they did the cleaning, they actually reflashed the ECU (don't know why). She drove out of her way to see me at work today. No residue on rear bumper and the exhaust smells clean, no unburned fuel odor The engine runs at proper idle with no fluctuations.

I told her it would take a few cycles (explained to her what a cycle was) for the ECU to remap everything.

thanks

 

[DarkFireGT]

I would still run Seafoam through it if they put "injector cleaner" in it. Most of those products just gunk up the engine more.

 

[fallenauthority]

BINGO!!!

After they did the cleaning, they actually reflashed the ECU (don't know why). She drove out of her way to see me at work today. No residue on rear bumper and the exhaust smells clean, no unburned fuel odor The engine runs at proper idle with no fluctuations.

I told her it would take a few cycles (explained to her what a cycle was) for the ECU to remap everything.

thanks

Im sure they didnt reflash the ecu, it probably had a CEL from running cleaner through it, they probably do what my shop does, run a cleaner through a vacuum line, most likely the brake booster line, into the intake which is actually more of a intake cleaner really but it is marketed as fuel injection cleaning. We have cars that will throw a CEL when its done and sometimes pop one up an hour or two later and we clear it and it stays off. Sounds like your problem was solved no harm no foul.