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911 Smoking when first started

  #1  
Old 10-09-2007, 03:07 AM
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Join Date: Oct 2007
Posts: 3
Default 911 Smoking when first started

Hi Folks,

My first post and I didtry a search on 911 smoke. No hits

I'm looking after my neighbourscars while they are away, starting them weekly, letting them idle, small revs, idle etc.
Their2002 911 Targa has me concerned. ( 60,000k's on the clock )

When I tried to start it this afternoon, it failed to start with a 3-4 second ignition on, no throttle. Waiteda few seconds and tried it again with no throttle and it started this time, but produced a large volume of blue/greysmoke for about15 seconds. The smoke then stopped.

To give an idea of the quantity ofsmoke, it filled the 8 car garage to the point it looked like a mild fog andas it was making me feel nauseas,I needed to start the underground garage exhaust fans to remove the fumes.
The car has always smelt sickenly rich on idle.

This is their first Porsche and I thought I would ask the question to you folks, so thatI may be able to give a heads up of what the problem might be when they return home later this week.

Thanks for any helpfull advice,

Cheers,
Phil
 
  #2  
Old 10-09-2007, 07:06 AM
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Join Date: Apr 2005
Location: Overland Park, KS
Posts: 3,532
Default RE: 911 Smoking when first started

Completely normal since not only does oil seep past the valves and into the combustion chamber on a horizontal engine, but there was probably some extra fuel in the chamber from cranking the first time.

If it smokes more than a minute after startup, then they probably have a bad oil air seperator.
 
  #3  
Old 10-09-2007, 07:54 AM
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Default RE: 911 Smoking when first started

Thanks Doc for the quick reply,
 
  #4  
Old 10-10-2007, 01:26 AM
Join Date: Dec 2006
Location: USA
Posts: 194
Default RE: 911 Smoking when first started

ORIGINAL: PorscheDoc

Completely normal since not only does oil seep past the valves and into the combustion chamber on a horizontal engine, but there was probably some extra fuel in the chamber from cranking the first time.

If it smokes more than a minute after startup, then they probably have a bad oil air seperator.
Hi, Doc, I seems like this is very comment, why don't Porsche fix this problem so that we all not going to get all concernfrom time to time?
 
  #5  
Old 10-10-2007, 04:24 AM
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Join Date: Oct 2007
Posts: 3
Default RE: 911 Smoking when first started

Yes tinchao, It does seem unusual that it's so common and considered normal.

As Doc indicated, the fact that their was excess fuel in the chamber no doubt contributed to the excessive smoke.

Did a search for AOS and I quote Mike Focke;

"A quick puff of smoke occasionally on startup is not at all unusual nor is it a sign of the AOS failing as long as it is only at startup. It is a characteristic of the flat-six engine and the way oil sometimes drains. You should check inside the AOS tubing where it goes into the air intake for heavy oil in the tube before removing/replacing the AOS. A light coating in that tube is normal. "

Doc's explanation makes sense given the orientation of the engine, but to a novice it seems unusual thatoil seepagewouldn't have been factored into the enginedesign. Smoke at anytime from a prestige vehicle is 'not a good look'
I wouldnt consider this a 'quick puff of smoke' butit did stop.
 
  #6  
Old 10-11-2007, 02:54 PM
Join Date: Sep 2007
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Posts: 611
Default RE: 911 Smoking when first started

Having read the initial query, my diagnosis was oil seepage down the valve guides. Doc has more experience of the flat six, but this is not an uncommon feature on all overhead cam engines that use a cam follower that encircles the valve springand valve. As the cam follower goes up in down in itsborein the cylinderhead it acts as a pump that pressurises oil down the valve guide, and produces a bit of smoke.
We seem these days to feel that a bit of smoke is bad, to me it shows that we are getting a bit of lubrication around the business end of the combustion chamber - this is actually good if you are looking for high performance as it stops pick up and wear.
Iraced in themid 60's a Lotus Elan which had a 1558 cc 4 cylinder DOHC based on a Ford 1500cc 4 cylinder engine. I got in excess of 155 bhp out of it etc. But it only did 200 miles to a pint of oil. Was a crap engine - no way, but it did go like "**** off a shovel".
Remember if it is going well and is using a bit of oil thats OK. If its using lots of oil and its not going well thats probably a problem but new valves and guides are always a problem especially to replace. So if it goes Ok let it run.
So using a bit of oil is not all bad!
Big Bob
 
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