Help, Slight White Smoke Out Of My Exhaust!!! - PeachParts Mercedes-Benz Forum

mike690003 · #1 06-30-2003, 07:52 PM

Hello Board, almost everytime when I am at a stop light, I notice a slight puff of white smoke out of my exhaust. My oil smells a lot like gas and My exhaust has a high smell of gas also(my car drinks gas like a Hummer!!, serously!!). I think that there is a problem with my fuel/air mixture(running too rich). My car's mixture was "adjusted" a while back, by a mechanic, and I think he screwed it up. Are those symptoms and indication of me running too rich?

I think that I am running too rich therefore leading to high amounts of gas in my oil, therefore leading to my oil being "burned off", therefore leading to the white smoke??

Am I correct?? ANY SUGGESTIONS???

I know:
Black Smoke= Running Rich
Heavy white smoke=Burning Oil
Light white smoke=coolant(head blown!)
VERY VERY Light smoke=water in gas

#2 06-30-2003, 08:56 PM

White smoke is generally not the symptom of an over rich fuel/air mixture. It would be black smoke.
White smoke normally come from ''water'' being evaporated by the ignition process. Water can only come from either a cracked block/head or a faulty head gasket.
If it is white smoke before the car has not reach its normal operating temperature, this is normal, Don't loose sleep over this.
JackD

psfred · #3 06-30-2003, 10:09 PM

Look at the exhaust pipe -- if it is liberally coated with soot inside and has a ring of fresh soot on the outside, you are definitely running rich.

Several possible causes -- improper adjustment (check engine light should be on, but not always), leaking fuel distributor, blown EHA, restricted fuel return.

If this started when adjusted, it was done wrong. It's fairly easy to check, get a multimeter (the on currently on the forum is a good one) and set if for duty cycle. Take the cover off the diagnostics connector on the drivers side fender (it screws on) and put the red lead in hole #3 and the black in #2. With key on and engine not running, it should read either 70 or 80 (depending on computer). Start and let the engine warm up. Duty cycle should float around 50% with some variation. If it reads 50 all the time, the O2 sensor is shot, if it reads 97% or 30% the mixture is so far out the computer cannot control it. Mine read 38% steady when I started working on the rough idle.

You can adjust it with a 3mm allen wrench if the adjustment port is open on the fuel distributor, or have it done by a reputable shop.

If you smell gas in the oil, it's likely not just a mixture problem, though -- you are pouring a huge amount of gas in there and need to get it fixed pronto. Oil diluted with gas won't provide adequate lubrication and you will wreck the engine from lubrication failure.

I suspect the white smoke you see is actually oil smoke from overly thin oil going down the valve guides at idle.

Peter

ejsharp · #4 06-30-2003, 11:06 PM

Or if the fuel mixture is ok then it could be that the oil you are using is simply too thin for the amount of miles that you have on the engine. An appropriate oil weight might be 15/50. That would stop the oil from seeping up past your piston rings and thus eliminating the white smoke. I use Mobile sythetic 15/50 in my 87.

mike690003 · #5 06-30-2003, 11:14 PM

Quote:

Look at the exhaust pipe -- if it is liberally coated with soot inside and has a ring of fresh soot on the outside, you are definitely running rich.

Oh yes, there is black soot inside, and that infamous black ring around my exhaust.

Another thing to add; I use "Quaker State Higher Mileage" Oil 10w-30, is that oil too thin??

should I use 10w-40 or 20w-50??

I dont want to start another oil thread.

ejsharp · #6 06-30-2003, 11:22 PM

I would definately use the heavier oil... unless you live in Siberia or neighboring surrounds.

psfred · #7 06-30-2003, 11:25 PM

Pull your plugs and see if they all look the same, too -- if you have a bad injector or two, they could be flooding fuel in unwanted.

probably the o2 sensor, though....

Change the oil pronto -- if you can smell gas in it, it's too thin.

Peter

mike690003 · #8 06-30-2003, 11:29 PM

Quote:

Another thing to add; I use "Quaker State Higher Mileage" Oil 10w-30, is that oil too thin??

should I use 10w-40 or 20w-50??

I dont want to start another oil thread.

I live in Miami,Florida

drbrandini · #9 06-30-2003, 11:34 PM

20w-50 with the Miami heat..... pun intended

ejsharp · #10 06-30-2003, 11:36 PM

For a warm climate like Miami I would go with 15/50 made by Mobile. It's sythetic but worth the engine life you will get from it.

20/50 would also work but I don't know who makes that blend.

mike690003 · #11 06-30-2003, 11:43 PM

Whoa!! I was running 10w-30 in my car?? Thats way too thin, AND MY CAR IS RUNNING RICH!!! I'm burning a candle on both ends here!

Its a good thing I only drive 75 miles a week!

I hardly drive, Miami traffic is crazy!!

20w-50 it is!!