pat056

Due to an auto accident I haven't been able to drive my 1999 996 for over a month. After finally getting it started, It had a miss and a hint white smoke coming out of passenger side exhaust. So I drove it for about 2 miles and the check engine light would flash then stop. The longer I drove, the less frequent the light would flash. I was taking a 75 mile trip and decided NOT to drive it. I took it back and let it idle for a minute while I repacked my stuff in my truck. When I started to accelerate the 996 to it's parking spot white smoke bellowed only from the right (passenger) side exhaust. It looked similar to AOS failure I've seen but AOS replace a year (less than 10,000 miles) ago.
Could this be some residual oil in a cylinder form extended lack of use? I really haven't had time to investigate but plan was:
-Insure no oil in coolant tank
-check right side for any leakage of oil that could have possible leaked into spark plug possibly fouling
-Even thought about driving it longer to see if whatever was causing the misfire (condensate in cylinder, etc.) could burn itsself off. The miss was improving the longer I drove the car.
I know the last ideas could be dangerous, but would think AOS would bellow smoke from both exhaust. Plus it didn't continue to bellow like AOS failure more a large puff that quit once the car was moving.
Any ideas or other directions to look?
Risk of driving the 7 miles to work?

ivangene

right is left - the exhaust crosses over

check the oil and filler tube for watery stuff

might just need to be driven - esp if you only go 7 miles to work - the motor could be filling up with water from the air and not burning it off

change the oil @ 1-2k miles if driving lots of short trips

kromdom

have you tried removing the oil filler cap WHILE car is running?

Imo000

Pull the stored codes and go from there.

69gaugeman

If it is white, that is a sign of water or coolant.

Black is fuel, and blue is oil.

Like Imo000 says. What are the codes? That is the best starting point.

If it gets better with use, I would drive the seven miles and see what happens. But that is me. Just keep your ears open and leave the radio off.

targa996

White smoke probably water ..if you drove 2 miles and were still seeing it I don't think it would be just condensation in cylinder. Is water level low ? Look for oil in coolant ? Try to pull oil filler cap with engine running .. If aos you might feel some vacuum. Any goo in filler tube ? Pull oil filter.. What does that look like ? Could be head gasket but in '99 s also cracked cylinder wall / head. How many miles on engine ?

KrazyK

Could you clarify what you mean? Wrecked and repaired by shop? Damage?

+1, your car is trying to tell you something.

Macster

It is never a good idea to continue to run an engine when it is behaving abnormally. So my advice is to not drive the car 7 miles to work. In fact avoid running the engine at all. Any engine running really should be done by a qualified tech as he diagnoses the source of the engine misbehavior.

The flashing CEL was likely due to one or more "rich" misfires. The flashing CEL was signaling the converters were at risk.

It was probably not due to collected oil. While the engine can smoke upon initial startup from residual oil allowed into the intake by a less than perfect (or defective) AOS the smoking is short lived and almost never -- never in my experience -- accompanied by any engine misbehavior, unless of course the AOS is indeed bad.

Under what conditions was the car left unused? Parked outside in the weather? Parked in a humid/damp location? Was the battery kept topped up?

How fresh was the gas that was in the tank? A month is not that long but if the gasoline was old/stale to begin with and even teh wrong (out of date) seasonal blend. In short "bad gas" is a possibility.

The behavior suggests damp coils with marginal electrical connections to the engine wiring harness. What is the mileage on the car and how fresh are the plugs and coils?

That the behavior improved as you drove the car suggests dampness that the heat of the engine dries but that it didn't get better right away suggests the dampness is more than just damp coils but something a bit deeper too at the electrical connectors.

Whenever a car sits unused for any time -- and a month is plenty of time -- there is always the concern about rodents getting at the car.

What to do?

Well, you should start and finish by taking the car to a qualified shop for professional diagnosis and repair.

If you want to delve into this yourself, well...

Check the car over thoroughly for rodent sign. Look for trash/litter or worse on top of the panels that protect the underneath of the car. Look on top of the engine. Check the intake and cabin air filters. Check the carpets for any signs of missing carpet nap.

If the CEL is on read the error codes pronto. Be sure to read all error codes. There could be error codes besides the suspected misfire codes. There might be pending or permanent error codes and these error codes might be helpful.

pat056

Thanks for all responses so far.
-Car not involved in wreck, driver was
-120,000 miles and is currently due an oil change. Anything to gain/lose in changing the oil and filter before restarting and looking at filter for xs plastic metal etc.?
Car sat outside and battery was just about dead had enough to get started. That was Saturday so hopefully the 10-15 minutes run time allowed for the battery to charge.
-Check engine light stays on because I'm too cheap to replace secondary air pump. A rennlist member was nice enough to give me a pump (yes, I said GIVE) and I replaced with no improvement. I suspect the pump to not be the problem at all but a vacuum leak that started when a sub par mechanic (me) replaced the starter. Back to topic: So the flashing is what scared me.
-It did, however get significantly better as I drove the car and virtually went away when I allowed the rpms to get to 4000-4500
- Plus and coils are in dire need of replacing time wise. I replaced all plugs myself around 80,000 miles and 2 cracked ignition coils.

If anyone wants to add adjust their recommendation based on my follow-up please feel free. This time of year and my schedule, I may not get to any of this until next week but if anything I'll trickle the battery, add some stabil, check for rodents, ck. connections, and general overview of engine by highly skilled Porsche mechanic (NOT) with 4 broken ribs.
Or probably do the correct thing and call AAA and tow it to ProTec in Greenville SC since I won't be driving it anyway and DO have broken ribs that minimize my ability to do ANYTHING...think I just talked myself into the correct answer.

Imo000

SCAN IT!!!! I assume when you broke those ribs, they scanned/xray you too. Same idea here too. Untill you get the codes, it's all a guess. But first, fully charge that battery.

Macster

Battery has to be suspect. Alternator too, though not nearly as much as battery.

The other day at a dealer was talking to a tech about batteries and how when they start to go bad can affect a car and he had a Cayenne in that would start and run just fine, for about 5 minutes. Then the dash would light up like crazy the engine would act up then die. Let the engine sit a few minutes and it would start right up and do the same thing.

The tech's diagnosis? Alternator. The battery would do its best to supply power but it just is not up to what these cars need.

Used to be a coil needed 9 volts (or thereabouts the exact voltage I forget now) to work. Seems with less than 9 volts the collapsing electrical field was not sufficient to generate the high voltage pulse.

Modern high powered coils might need more voltage. Remember I touched upon the flashing CEL in an earlier post?

To expand: The flashing CEL is indicative of improper combustion that is feeding or can be feeding unburned gasoline to the converters where it can burn and overheat/damage/ruin the converters.

Such a condition could come from not from bad coils per say but coils that simply do not have enough voltage to operate. Stale gas could of course contribute to the engine's behavior. There are always 2 problems, unless there is just one problem or 3 or more problems.

That the symptoms diminished at higher rpms suggests the alternator is doing something but it should be able to keep up even at idle, unless there is something wrong with the alternator, or more likely the battery, since battery problems are more common than alternator problems.

I do not think a short drive is sufficient to replenish the battery. Even with a brand new battery in my 996 Turbo I noted the other day it took nearly a half an hour of running around before the voltmeter reading dropped from nearly 14 volts to something less. To me this suggested it took that much driving to just replenish the battery after the engine start.

I know I drove my sister's new Infiniti about 15 minutes a while back and I thought everything was fine. Engine fired right up and idled fine and the car drove fine. But after a couple of months when I went to start the engine again the battery was stone cold dead. Brand new (Nov. 2011) car and battery. It was fine in the warmer months but the cold really hammers on lead/acid batteries.

Anyhow, a battery and alternator test I think is called for, at least.

If before this if you want or if you want a tech to drop the oil filter housing and pour the contents into a *clean* pan that's ok, too.

I can sympathize with the ribs. While I've never had any rib problems I have a bone spur in my left shoulder and I can't even comb my hair or tuck in my shirttail, let alone remove the flaccid worn out rear trunk lid struts on my Boxster and replace them with new ones.

Sneaky Pete

Could you choose a better word than flaccid? I resent that...carry on

kromdom

+1000. I support this

Pac996

How much gas was in the tank while sitting? Full tank has less area for condensation to form leaving water in the tank. Light aircraft the trick is to top off every time before parking even short periods. Something about sputter sputter uh....... oops!

69gaugeman

Awesome!