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968 black smoke on startup?

Just wondered if it's at all normal for black smoke to come out on startup -

it goes away after the engine is warmed up so i dont think it is burning oil...
Old 04-05-2003, 06:07 AM
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Mine doesn't...............
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Old 04-05-2003, 12:55 PM
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Black smoke is usually an indication of a rich air-fuel mixture. Since the ECU doesn't regulate the air-fuel mixture in closed-loop mode until the O2 sensor warms up, that's probably all it is. Once the O2 sensor reaches operating temperature, the ECU regulates the air-fuel mixture better and the rich condition goes away.
Old 04-05-2003, 02:40 PM
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Sounds like you have a leaking fuel injector that pools up while the car sits for a while...when you start it, there's too much fuel in that cylinder which burns poorly and makes black smoke.

How many miles on the car?
Old 04-05-2003, 09:34 PM
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80k miles on the car, and recently - something which might be of relevance - the engine oil warning light has been on...

but i had the car serviced about 200 miles ago, and oil changed - as well as all oil seals changed.... the oil level is fine too....
Old 04-07-2003, 11:41 AM
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Quote:
Originally posted by SnoopDogg
80k miles on the car, and recently - something which might be of relevance - the engine oil warning light has been on...

but i had the car serviced about 200 miles ago, and oil changed - as well as all oil seals changed.... the oil level is fine too....
Engine oil indicator means you're a quart low. The service place might not have put enough oil in your engine if you're confident that it's not leaking. Just check your dip-stick and top off the oil if needed.

The engine oil light shouldn't be related to the black smoke you see on start-up.
Old 04-07-2003, 12:19 PM
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the dip-stick doesnt have any indication marks for low or full, dont know how far up is full.... any indication in maybe centimetres from bottom??

also does it matter if i mix 2 different types of oil, because i dont know which type they put in when it was serviced...
Old 04-07-2003, 12:40 PM
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You do have a leaking injector, but you also may have a bad piston ring. I know that oil burns white/greay/blue. okay, but if it sits in a hot engine and breaks down for a few hours then is ignited it will burn black. Also, fuel is dripping into the same cylinder. What is happening with the fule is the same as dumping gasoline into a metal bucket and throwing a match at it.. what you get is a concussion effect, and this creates alot of black smoke "carbon" which is the result of burning HOT fuel. "it's sitting in a hot Cylinder right?

Check the injectors.. and you may need rings. 968's are notorious for beaing driven exceptionally hard because they were pretty mean cars.also, if you're running the car on low oil, you may have created this problem yourself.
Change the oil and use Mobile 1, you may want to use an additive for the rings and Valve seals, (which coiuld also be a culprit).. wait the rings are metal.. just worry about the valve seals....
If you're clutch is slipping, you're leaking oil out of the rear and onto the Clutch, which is where you're oil may be going..

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Old 04-07-2003, 01:03 PM
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Nope, clutch is not slipping, and as far as the oil dip-stick goes, if you know the small metal ball type of bump about half way up, the oil is slightly higher than that....... which looks high enough to me, but like i said it doesnt actually say full, empty etc on the stick....
Old 04-07-2003, 01:10 PM
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what color is the oil..
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Old 04-07-2003, 01:13 PM
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how does the coolant look
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Old 04-07-2003, 01:14 PM
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it's about 10.30 here, so i cant really go check at the moment, too dark, but i'll check it tomorrow and post what color they are.... from what i remember oil is kinda like honey colored on the stick, but i'll check in the actual oil tank.... dont know about coolant...
Old 04-07-2003, 01:39 PM
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Dude from your description it sounds like there's way, WAY too much oil in the engine. The graduations are located at the very bottom of the dipstick, certainly not half-way up! You'll find the metal on the end staggered a bit, with two graduations [quart low and full] about 1-2" from the very bottom. Sure the servicing station didn't think your car was a 911 and put 10+ quarts of oil in??
Old 04-07-2003, 01:44 PM
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uh-oh...
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Old 04-07-2003, 01:57 PM
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ummmmmmm what would happen if they did put too much oil in? it was a porsche specialist i took it to, so they SHOULD know the difference..... please tell me no major damage??
Old 04-07-2003, 02:31 PM
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Bigest problem with running the oil to full is possibly blowing seals. Also the bottom of the crank will stir up the oil causing it to to mix in alot of air. When the oil froths up the system can not circulate it. You should be able to see this on the dip stick though. 200 miles is probably not enough to cause damage though. I doubt the oil is related to your black smoke. Is the oil pressure guage reading pressure? I would deffinatly fix the oil light imeadiatly!!!!! An oil change doesn't assure that there is oil pressure.

What ever richens your mixture and adjusts your airflow at start up is probably malfunctioning. I am not familiar with 968's on my 924 I would check the auxilary air valve and the cold start valve. Leaking injetors are common on 924's but usually there is a problem with starting. If all the gas has leaked out of the line the spark plug has trouble firing and it takes a few seconds to build up fuel in the line. It is relitivly easy to check the injectors. Just pull them one by one and stick the tip into a plastic coke bottle. If the spray is cone shapped and each injector has the same spray pattern, and they do not drip after you stop cranking the engine they are probably good. Make sure to ground the coil wire so the car wont try to start while you are testing the injectors.
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Old 04-07-2003, 03:39 PM
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ok just checked the coolant is blue, the oil like i said honey kind of honey color.... and yep the oil is low - last time i cheked it i dont think i let the car stand for long enough, oil must have still been circulating....

Another thing, i have found a large amount of carbon against the wall in my garage where the exhaust is, so a lot of carbon is coming out on startup.... ??? any suggestions??

and as for checking the injectors, im not mechanically minded nor able past changing a spare tyre unfortunately...
Old 04-08-2003, 12:03 PM
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MAN IT'S TRASHED JUST SELL IT TO ME FOR 1K..
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Old 04-08-2003, 12:28 PM
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Odd blue coolant????? Shouldn't the coolant be green or possibly orange? Oil sounds ok but have your mechanic fix the oil light. Its a bad idea to drive with it on. I am assuming that your oil pressure guage is showing pressure. If the oil pressure guage is not working then dont even try to start the car.

As for the black smoke on startup cant say much about 968's. Does it do the same thing when started hot or cold?
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Old 04-08-2003, 12:32 PM
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Quote:
Originally posted by Roger Hall
Odd blue coolant?????
Not odd, it's the good stuff. BMW uses it, too.
Quote:
Oil sounds ok but have your mechanic fix the oil light. Its a bad idea to drive with it on. I am assuming that your oil pressure guage is showing pressure. If the oil pressure guage is not working then dont even try to start the car.

Late 944's and 968's have an engine oil light UNRELATED to oil pressure. There's a sensor in the oil pan that signals the engine oil light when oil level is a quart low and below. The oil pressure light is a separate BAR that lights up on the pressure gauge and triggers the idiot [!] light as well. This indicates low oil pressure or a failing oil pressure sender.
Quote:
As for the black smoke on startup cant say much about 968's.
They aren't supposed to smoke.
Old 04-08-2003, 02:01 PM
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