Black smoke usually indicates burning oil.

 

Noooo
From where. My car has only 91k only

 

It could be poor air mixture. Check your plugs and air filter to start with.

You could "smell" the black smoke, it will tell you if it's oil or air.

 

the smell look like CO2

 

I am having the same issue...once heated up the smoke starts.
I had a compression test and one cylinder showed low pressure, but the car runs perfectly!
I changed a bad MAS, fixed a vacuum hose @ brake booster check valve and the plugs are all clean...
Will a broken cat (which I have) cause any of this???

 

Black smoke is not oil. Black smoke is fuel that has entered the cylinder and hasnt been burned. Blue smoke is oil.

 

I disagree, blue smoke indicates burning oil, black smoke is an indication of runnin rich. Try cleaning the MAF, changing air filters and check plugs. Also, malfunctioning O2 sensors will cause rich condition to occur. If left too long, it will destroy the cat.

 

560:
when fuel gets in the oil it can burn black, but usually is related to fuel being dumped in the oil which is usually a problem related to something fuel related(ie injectors etc)
you can usually smell fuel on the dipstick.

 

4benzes - if you look at the times of our posts and what we each said, I think we were saying the samething at the same time - I was not disagreeing with your post, but I will still contend that if black, its rich, and if rich, it's a product of incomplete combustion caused by incorrect fuel/air mixture - which could be injector (leaking by) or MAF sending incorrect signal to the computer which in turn sends incorrect signal, or bad O2 sensor sending incorrect signal, or misfiring plugs or clogged air filter - any which will cause incomplete combustion.

 

Low pressure cyclinder may have a cracked ring on the piston ,which depending on how bad its cracked the amount and color of the smoke and if it's not letting the cyclinder fire correctly product a blacker smoke. Is the car using oil more than normal and running smooth with not even a hint of a skip?

 

Concerning the running of the car, yes, it runs very smooth. Oil consumption? I need to check as I have been afraid to drive too much for fear of causing more damage.

I USED to have the gas smell (along with a jerky hesitation) but the vacuum line and MAS replacement fixed that.

The new plugs were running clean even though the smoke condition persists. The smoke starts once the car temp is around 100 degrees...I am wondering if any crap in the "bad" cat has anything to do with it? I'm going to get the free flowing cats put on anyway, so I'll check that.

The (warm) compression test brought the pressure back up a lot (it was 45lbs cold and 165lbs once warm and oiled). The other cylinders were around 193lbs.

I tend to agree with your cracked ring assessment. But I wanted to see if it was something else (wiring issue, CO2, etc.) which may be less costly!

Thanks!!

 

Thanks guys for your answers....
But any one tell me where is the O2 sensor locate. I clean the both MAS's, the air filtters & the spark blugs are prety new ( less than 7000 mile ) but i will change it soon

 

White smoke: White smoke is caused by water and or antifreeze entering the cylinder, and the engine trying to burn it with the fuel. The white smoke is steam. There are special gaskets (head gaskets are the primary gaskets) that keep the antifreeze from entering the cylinder area. The cylinder is where the fuel and air mixture are being compressed and burned. Any amount of antifreeze that enters this area will produce a white steam that will be present at the tailpipe area.

Blue (or gray) Smoke: Blue smoke is caused by engine oil entering the cylinder area and being burned along with the fuel air mixture. As with the white smoke, just a small drop of oil leaking into the cylinder can produce blue smoke out the tailpipe. Blue smoke is more likely in older or higher mileage vehicles than newer cars with fewer miles.

BLACK SMOKE: Black smoke is caused by excess fuel that has entered the cylinder area and cannot be burned completely. Another term for excess fuel is "running rich." Poor fuel mileage is also a common complaint when black smoke comes out of the tailpipe. Black smoke out the tailpipe is the least cause for alarm. Excess fuel will usually effect engine performance, reduce fuel economy, and produce a fuel odor.

How did the fuel get into the cylinder in the first place? Some of the causes of excess fuel are a carburetor that is out of adjustment, a faulty fuel pump, a leaky fuel injector, or a faulty engine computer or computer sensor. If black smoke is present, check the engine oil as in the white smoke example to make sure excess fuel has not contaminated it. Do not start the engine if a heavy, raw fuel smell can be detected in the engine oil. Call your mechanic and advise him of what you have found.

I hope this helps you determine what could be causing your engine smoke, and the possible reasons behind the smoke.

 

Thanks mlrb2113...
Its black smoke, so i think i gonna take it to the mechanic...

 

THe 02 sensors are located on your exhaust system under the car near the cat.

 

Thanks....

 

i took the car to the mechanic & we diagnose it.
the smoke came from the MAS the airmass reading 0 there is no output at all from both airmass's

 

I suppose that makes it run too rich; not enough air.
Exactly what does an MAF do (if you know & have time)? I'm clueless. I only know that it's one of thousands of things we got that weren't necessary in the '50s and '60s and can't be any more necessary now.

 

Where does the MAS get it's power source or info from to allow it to have a reading is the next thing to find out. I find it hard to believe that if you have two,both went bad at the same time. I didn't realize some r129s had two MAS's.

 

The 600SL, SL600 & SL72 has 2 air mass

 

The MAS (mass airflow sensor) is one of the components that sends a signal to the computer (ECU) with which the computer uses to send signals to either adjust timing, plug and injector "fire" duration, all in attempt to acheive perfect stoichiatric ratio of combustion.

 

WOWEE! No wonder I had to pay $90,000 for mine, and it runs nearly as good as my '57 Pontiac did.
Why don't we get better gas mileage? Must be that there's always something that isn't working.

 

I find it weird your mechanic mentions there is no signal from your MAS sensors, and all the car does is smoke a bit.

If those were gone, you'd be having more severe symptoms....

 

I sow the reading when the car was hocked to the computer & he give me the print out
Plus i feel the same, its weird that both MAS's read 0 at less one has some read out not both

 

I change the MAS's ( uesd ) & the smokes gone.
But now my next step it buying new MAS's, cleaning the injectors & changing the O2 sensor.
But i will do it when i got extera money cause am sure. It gonna cost toooo much.
Any id how much is the new MAS.... Cause here in my countery its dam expensive more than 1100$ each

 

Autohausz has them for 305.00 dollars a peice.

 

Update - My smoke issue has cleared up. I think the MAS needed to recalibrate...I've been running the car over the past week and all is well...I added some Sea Foam to the fuel tank as well as to the oil...All is well!! Amazing..

 

Great! Now I'd get the Sea Foam out of the oil!!!