perryinva

Strange thing happened the other day. I had backed the car out on to a very steep part of my drive, (which is about as long as the car) to keep her off the sidewalk, engine side downhill, while I did some work in the garage. Car sat out there like that for about 6 hours. I then pulled the car back in the garage and raised it up on my low rise EZCarlift to remove the front bumper cover and clean out the rads. ( It's a lot easier to remove the cover if the front wheels are off, and the fore most inner liner is disconnected. Rads had been cleaned in 2008, but only like 15k miles ago, so I didn't expect much, but figured it would still be smart to check them. actually quite a bit of grass & leaves between the two, but nothing that would affect performance, but I digress)

So the car was up on the lift for 2 days. Just checking things out, like the single drop of oil that is always on the Guardian MCD oil plug, as well as a general inspection. Everything looks fine. Dropped the car down on Tuesday night. On Thursday, go to drive the car to work, and notice, in the rear view mirror, a minor amount of smoke. I figured, when parked at that steep angle, some oil might have pooled somewhere, and that was the result. Backed it down to the street, and realized I forgot my briefcase in the garage. Ran back in, got it, get in the car, and think to myself, "Is it running a little rough, or is it my imagination?" And literally, as I finish the thought, the CEL comes on "Check engine - Drive to garage". WTF? I'm already late for work, so I just pulled it back into the garage, (after all, that's what it said to do) and on Friday throw on the Autoenginuity OBDII software. No codes? Not even any stored. Start the car, CEL is gone. Is there such a thing as a temporary CEL that actually clears over night? Car runs fine again. Could pulling little oil into the combustion chambers cause a fuel rich condition to throw a CEL. Any ideas?

white out

My only idea: maybe a little blow-by oil was stuck somewhere in the intake manifold and dripped down into a cylinder, the resulting burn off set off a CEL.

Ubermensch

I'm interested to hear any good answers to this problem. I've been storing my car in a public garage in which the spots that are isolated are also at an angle. I'm wondering whether it's a very good idea to store and subsequently start the car when the oil is pooled in one direction.

Macster

Some error conditions can cause the CEL to light up but as soon as the condition goes away the CEL can go dark. The error code or codes associated with this while not active can be stored in the permanent section of the DME. From this section only the DME can erase the error code once the triggering error has been absent for so many warm up cycles.

Depending upon the degree of oil being burned this can have caused a temporary misfire condition. I note you engaged in the type of "driving" that most often brings out the smoke in these cars. The back the car up or move the car around a tiny bit then shut off the engine driving.

(New/used cars on the dealer's showroom floor and lot get this usage a lot and as a result new/used cars often smoke upon startup. The techs see this a lot when dealing with new and used cars and when I ask them about this they tell me they just note the engine is otherwise running ok and with no other symptoms and if the smoking stops after just a moment pay it no further mind.)

Anyhow, the code could have been something else too. If you have no way to read the permanent error codes you'll not know.

Absent any abnormal behavior now, and with vital fluids (oil and coolant) levels ok, you can just drive the car. (You are of course free to, and I encourage it, to consult with your trusted tech to get his input.)

If there is something going wrong the CEL will come back on. Even if it does not if the engine starts acting up shut off the engine ASAP and get the car flat bedded to a qualified shop for diagnosis.

perryinva

Yes, that is exactly what I have been doing. The Autoenginuity software (with Enhanced Porsche DTCs) does read all stored codes and translates them. It did a perfect job identifying the exact right one, when I had a loose coil when I first got the car. It even has a Cylinder Roughness Rating, and an over all engine roughness, which is normally reading around 0. No misfire counts, either. All fluids look perfect. New AOS, water pump coolant, oil, oil cooler O-rings, etc. Just odd I though that something like that would cause a CEL then disappear, and not store it.