Puff of smoke on start up......

Sunroof · 10-18-2002, 05:57 AM

Okay, so I do not use an 02 meter as my mechanic long suggested........"it s a feel thing on mixture adjustment". I believe I am adjusted fine on the mixture end; however, every morning with hand throttle up I get a nice healthy puff of smoke and thats it...........poof, its over and away I go singing along with the Grateful Dead! Should I be concerned? Through the years many have said, "smoke on startup is normal for the older vintages".

My 2.4 was rebuilt 43K ago with a 7 grand bill, does not leak a drop and is as tight as a drum............valves were re-done, so I discount valveguides.

Just was happens after standing cold all night or day that makes it smoke? Fuel injectors slightly leaking? Valve adjustment needed?

Either someone slap me in the face and insist I use an O2 meter, or just tell me life is normal with what I see...........

Thanks

Bob
73.5T

cary · 10-18-2002, 06:50 AM

Do a search. You'll have hours of reading. Try start smoke.

Mine does it on occasion. Depends how long between start ups. And was the car fully warmed last time it started up.

If my memory serves me right. Warren...Early-S-Man had a great explanation on what causes it.

masraum · 10-18-2002, 08:06 AM

If I let my car idle for 10-15 secs before I turn it off it doesn't puff as often. If the smoke is white or blueish then it's the regular oil puff. If it was gas then the puff would be black smoke.

Glasgow 911SC · Glasgow 911SC's Garage

Due to the very nature of a boxer engine, oil can seep past the pistons if left standing for a while. I remember reading that Subarus & BMW motorbikes (boxer engined) are similar in this respect.

Sunroof · 10-18-2002, 08:19 AM

Definitely blueish smoke..................I will try the idle for awhile to see if that changes anything.

Thanks
Bon

bonedaddy · 10-18-2002, 08:45 AM

Had a similar problem with my 911. I would get a puff of blue smoke at start-up, but at no other time. There was no discernible performance problem, either. The classic symptom of worn valve seals. As I recall, I did a compression check, which indicated an anomaly in one cylinder. When I got into the head, I found a problem with a valve guide. Since I had the engine out, I decided to do an upper end rebuild, but I could have gotten by with just replacing the guide. No more puffs of smoke after that.

kristian85 · kristian85's Garage

Hullo,
It's entirely normal for a 911 motor. Aircooled boxers have two engineering characteristics that help cause the puff: aircooled design, larger tolerances than watercooled; and boxer, some seepage by piston rings.
Kristian
Seattle

speeder · 10-18-2002, 10:26 AM

Kristian is the winner here. One puff, even a big one, on cold start-up is normal. At the dealership, we could not start the new 911s and 930s on the showroom floor to drive them out because of this, we would push them outside and then start them. We could drive them INTO the showroom, no problem, manuever them into place, etc., no smoke. These were brand new cars w/ zero miles in the '80's.

No problem starting the 944s, 928s or Audis indoors.

Groesbeck Hurricane · 10-18-2002, 07:31 PM

What is your oil level when the vehicle is warm and idling? Some of the other explanaitions I have read state that if the oil is over full it will seep past the pistons over night and cause a puff on start-up. Just another thought...

speeder · 10-19-2002, 01:43 AM

Being over-filled may increase this (normal) phenomenon, can't say for sure, but as I stated above, a brand-new, correctly filled at the factory engine will produce a puff of oil smoke upon cold start-up.

Wil Ferch · 10-19-2002, 05:23 PM

Guys:
One more possibility to ponder about......
Even though you have three piston rings, and even thougn they may be installed with the gap at 120 degree intervals, ...they may turn. Once in a great while the the gaps may line up ( I propose)...and there is a better chance of momentary oil blow-by. After some running...the "randomness" of the gap locations returns ,and all seems normal.
Isn't that a possibility?

-- Wil Ferch

pwd72s · 10-19-2002, 05:31 PM

Yep Wil, IMHO, a very real possibility. As far as smoke puff on start up? In the words of dealership service managers of ANY make, to explain ANY symptom: "They all do that."

Groesbeck Hurricane · 10-20-2002, 08:25 AM

Did we reach concensus?? Start up puffs, usually not an issue with no other symptoms present?

I'd say drive and enjoy!!!

Samokin · 10-20-2002, 09:11 AM

It sounds like a worn valve guide or valve seal...