Troubleshooting smoke after cold(ish) starts

[TaffyJoe]

Hello, This is a plea for a sanity check before I go ordering parts willy nilly….

When I start my stock 3.2 daily driver (57500 miles), a drive goes like this:

• 0 - 20(ish) seconds : starts on first try and runs strong
• 20 seconds - 4 minutes : constant whitegraywithahintofblue(ish) exhaust smoke at idle, thins somewhat under acceleration
• 4 minutes - end of trip : Pure driving bliss

In mornings this includes some few drops of water. At lunch (after driving to work), the drips are missing and the smoke doesn't last quite so long - same in the evening on the drive home. Thought: shorter durations perhaps because the engine is not stone cold?

To be honest, the exhaust color looks white to me, but after I read about blue/black smoke I'm starting to see things.

Performance is wonderful up and down the tach in all gears, but the cloud of smoke that wraps around my Porsche while I sit at neighborhood stop lights, in addition to being a bit embarrassing , makes me wonder if she's running a bit rich until she's warm and the O2 sensor's sensitive bits heat up.

I've been reading about smoke/idle/rich/exhaust/oxygen/3.2 here, at Rennlist, and the PCA website and have learned so much my head hurts (two bottles of Anheuser World Select temporarily cured that). One thing I've read that sticks with me is that the Oxygen Sensor has a heating element that brings it up to operating temperature within a handful of seconds so that it may do its job before the engine is at its operating temperature. If this is the case, it seems that while the O2 sensor itself works (since life is smoke-free 4 minutes into any trip), the heating element may be shot. In my little world, it's a reasonable explanation of why I get so much smoke within half a minute of starting until the oil temp gauge moves a bit north.

Which (finally) brings me to my questions:
Is this a reasonable thought process? Or are there other things I should test/consider?
I plan to replace the O2 sensor anyway since I'm at 57500 miles, but I'd like to know if I'm blowing smo, er, barking up the wrong tree and should consider other components before ordering parts.

Of course some things have changed recently around the time the smoke screen started:

• Valve adjustment
• Oil change (Dino 20w50) ... just shy of halfway between dipstick marks when hot
• New plugs (gapped to 0.75 mm) ... old ones looked great, no black/wet/crust
• New fuel filter

Finally, the only other thing I know to throw in is that she does lose some oil (quart every 900 miles or so), but most of it falls on the heat exchangers and sometimes she leaves a drip or two where she's parked. Running strong @ 4000+ RPM and then rapidly decelerating doesn't change the exhaust pattern when warm.

After reading all of this, it seems I should probably invest in a good mutimeter and figure out how to test stuff other than continuity.

Thanks in advance for reviewing this and letting me know what I miss.

[Joe Bob]

Oil level sounds like too much.....even if you are leaking some....

You could be sucking some into the intake,,,,,

[movin]

I'm assuming the engine top end is original. Exactly the same symptoms my '87 started years ago, around 95,000mi. Typical for the '84 to '88 Carerra, the valve guides and/or seals are beginning to leak. I wish I knew this before buying the car, it would have steered me to a later year, >'91. It seems nothing can be done, just monitor oil consumption and when it gets to about 500mi/quart you're in for a valve job. I stopped using it as a daily driver, now drive it once a month in order to save up for the expense, at this rate I could go for years.
I would avoid Mobil1 in any grade. I found Shell Rotella pretty good at lowering the consumption and smoke a bit.

[TaffyJoe]

Thanks for the ideas...

I'll take the airbox off this weekend and check for oil residue. It could well have been a bit over full earlier.

If there were worn guides and bad seals wouldn't smoke be almost immediate and darker? It puzzles me that she waits 20 seconds to start the smoke screen routine.

Thanks for your help thus far.