E-Class (W124) 1984-1995: E 260, E 300, E 320, E 420, E 500 (Includes CE, T, TD models)

Rich fuel smell...02 sensor problem?

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Old Jan 3, 2009 | 04:50 AM
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luvmuzik66's Avatar
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From: Gledale,Ca.
1989 300E
Rich fuel smell...02 sensor problem?

I;m smelling a rich mixture from my exhaust, can this be caused by a bad 02 sensor? What are the other causes? I've recently replaced all the valve stem seals to cure the white smoke. I need help because I need to get this car smogged. Thanks in advance. And I get black smoke evrytime I ounch the throttle, parked or on the freeway.
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Old Jan 4, 2009 | 04:41 PM
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1994 C124 E320 Coupe - 1975 W116 280S
Curious about the fuel smell.

Black smoke means that you are burning oil. How many miles?
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Old Jan 4, 2009 | 04:50 PM
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From: Gledale,Ca.
1989 300E
Originally Posted by Chinny4290
Curious about the fuel smell.

Black smoke means that you are burning oil. How many miles?
I have 182000...but I think the white smoke is due to burning oil, and black smoke is a rich fuel mixture. I've already fixed the white smoke part by replacing the stem seals. And also, I want to know if the fuel distributor can also cause the fuel mixture problem.
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Old Jan 5, 2009 | 03:24 AM
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From: USR, NJ, United States of Americaland
1994 C124 E320 Coupe - 1975 W116 280S
White smoke of any kind means that it's a coolant issue. It's interesting that the white smoke was fixed from the valve stem seals.

Think of it this way. When you cause water to vaporize (the 50% of whats in coolant) it turns into steam, which is white.

When you cause oil to vaporize...or in the most direct way of saying it, burning oil, it becomes a bluish/black smoke.

However, as I just researched gray to black smoke can indicate a too rich air/fuel mixture which is from a wrongly adjusted engine, an extremely dirty air filter, or bad/clogged fuel injectors.

I don't know about the distributor though since nearly all the cars I've driven/worked on used coil-over ignition and is all ECU managed.

I'm still learning with my carbureted 280S. Maybe someone else can chip in.
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Old Jan 5, 2009 | 10:34 AM
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From: Gledale,Ca.
1989 300E
Originally Posted by Chinny4290
White smoke of any kind means that it's a coolant issue. It's interesting that the white smoke was fixed from the valve stem seals.

Think of it this way. When you cause water to vaporize (the 50% of whats in coolant) it turns into steam, which is white.

When you cause oil to vaporize...or in the most direct way of saying it, burning oil, it becomes a bluish/black smoke.

However, as I just researched gray to black smoke can indicate a too rich air/fuel mixture which is from a wrongly adjusted engine, an extremely dirty air filter, or bad/clogged fuel injectors.

I don't know about the distributor though since nearly all the cars I've driven/worked on used coil-over ignition and is all ECU managed.

I'm still learning with my carbureted 280S. Maybe someone else can chip in.
There are two things that can cause white smoke, oil and water. The valve seals were hard already when I took them out. They were barely grabbing the valve stem. They were so lose, the valve(s) were doing a free fall. A bluish black mixture base on my experience is a little rich mixture and bluish being normal. It only smoked in the morning start up and on acceleration. Like I mentioned, that has been fixed. Is there anyone out there to give a comment on this thread regarding the 02 sensor issue and the fuel distributor? What else can cause a ricj fuel mixture.

And if my injectors are clogged, there is no possibility for a rich mixture. It should be leaning out. My 2 cents.
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Old Jan 5, 2009 | 04:37 PM
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From: USR, NJ, United States of Americaland
1994 C124 E320 Coupe - 1975 W116 280S
Learn something new everyday
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