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Black smoke at startup

My 88 Jeep Wrangler sometimes blows black smoke when started. The smoke leaves a wet mark on the driveway that looks like someone took a spray can and lightly sprayed the area under the tailpipe. The smoke usually disipates rather qickly. From what I have researched, it is the fuel running too rich. Does this sound right on? Also, my gas mileage in the jeep is not the greatest (to be expected). Could the mixture have an adverse effect on the mpg as well?

As always, thanks to this group for the help....

Reply to
wbowlin
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Someone has replaced your engine with a diesel!

Carburated or F.I.? How cold is it in the morning?

Reply to
Stupendous Man

wbowlin did pass the time by typing:

If it didn't dissapate I'd think you had leaky valve seats and some oil was getting into the pistons. A vac gauge will tell you that.

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As old as your Jeep is, it could just be condensation in the exhaust system and leftover carbon getting blown out as the engine starts. Normally if there is an oil leak you get a nice blue/black cloud that follows you around.

Reply to
DougW

Do you still have the Carter and computer hooked up to it? It sounds like a combination of water (condensation) and soot spitting out, and the choke being on...

Reply to
Simon Juncal

I had a similar situation once. Black smoke, ran rough when started cold. Error Code was for an O2 sensor. I pulled the aircleaner and very very slowly poured Berryman B12 down the carb while hand-reving the accelerator to keep it running. Ran through the entire can. This cleaned off my O2 sensor and sprayed more black crap all over the driveway than you've ever seen. After the can was empty and the remaining B12 was burned, the motor ran like a top for years after. Never did replace that O2 sensor. _____________________________________________________________________

2003 TJ Rubicon * 2001 XJ Sport * 1971 Bill Stroppe Baja Bronco

"There is a very fine line between 'hobby' and 'mental illness'."

Pronunciation: 'jEp Function: noun Date: 1940

Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase') A small general-purpose motor vehicle with 80" wheelbase, 1/4-ton capacity and four-wheel drive used by the U.S. army in World War II. _____________________________________________________________________

snipped-for-privacy@gmail.com wrote:

Reply to
twaldron

That sounds like a properly working electric choke.

It is adjustable, however if you tune it so the black smoke isn't as bad, then it will be a pig to start driving when cold. They are a pig cold anyway which is why I prefer a manual choke.

The electric choke operates on a timer that has no bearing on how warm or cold the engine actually is so up here in Canada they go off way too quick and you have to either 3 foot drive to avoid a cold stall or wait a long time for it to actually warm up.

To see if it is adjusted properly, you can warm up the engine and open the air filter carefully with it still running. If properly adjusted, the choke plate will be wide open. If not there is a black cap with 3 hard to get at screws on it that adjusts.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >
Reply to
Mike Romain

Reply to
L.W.( ßill ) Hughes III

twaldron did pass the time by typing:

Try using ATF fluid. :) Your neighborhood will think there is a house on fire.

Reply to
DougW

I'm thinking this may be it. It only happens occasionally and it dissipates really quickly. It's just that when it happens it blows what looks like a light coating black spray paint on the driveway. This is usually as I give it a good bit of gas to start it in the cold. The jeep takes a little while to run real smooth in the cold, but once it gets warmed up it is fine. Like any other carburated engine I've owned....

I may give the vac gauge a look and also check out the choke as suggested.

Thoughts?

DougW wrote:

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Reply to
wbowlin

Water works just as well.

Earle

Reply to
Earle Horton

Not if your intent is to smoke out the neighborhood.

Reply to
billy ray

The best stuff to use is called Seafoam, you can get it at NAPA or Advance Auto. It was originally developed for the boating industry to decarbon engines. With todays fuel there is not an engine that does not have some kind of carbon issues you just may not know it.

Coasty

Reply to
Coasty

Reminds me of the first time I fogged my outboard for winterization. I didn't get to use the boat until 4th of July weekend. Of course, I was at the hippest, coolest, mack daddy marina on Lake Texoma, sitting on the ramp. We're talking drag boats, cigarette boats, Carver's, and more female eye candy than you can find on the Playboy channel. Even Dennis Rodman's Fountain was there. I was expecting a little smoke at the start. Boy was I wrong. :) _____________________________________________________________________

2003 TJ Rubicon * 2001 XJ Sport * 1971 Bill Stroppe Baja Bronco

"There is a very fine line between 'hobby' and 'mental illness'."

Pronunciation: 'jEp Function: noun Date: 1940

Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase') A small general-purpose motor vehicle with 80" wheelbase, 1/4-ton capacity and four-wheel drive used by the U.S. army in World War II. _____________________________________________________________________

DougW wrote:

Reply to
twaldron

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