My brother has a very sweet 78 SC with under 70,000 miles. It hasn't been started in about 3 months. He parked it one day when the druck pressure needle started jumping and then quit working. I suspect a short or loose wire. He started it today and it sounded fine and ran fine for about 3 minutes, then a huge billow of white smoke engulfed the car and garage. Any ideas? Oh, its a 3.0L, completely stock.

He'd owe me big time if I could figure this one out.

Just kidding, I'm the one who owes him.

Did it make any noises before/during the smoke?

Oh, did it smell?

no noise. not sure about smell.

Shirt arrived today. looks great. thanks

I'm sure I'll get grief for this, but I am willing to bet $5 that it's probably ok.
911's do shit like that. I'd push it out of the garage and start it again (monitoring it carefully) and see if
it'll warm up and stop smoking.

Use your own best judgement here, that's just what "I" would do.

glad you like the shirt!

How was the oil pressure.....gauge work at all?
How was the oil level gauge?

White smoke is oil.

You may not like my WAG.

Sean, It did smell, but he couldn't explain what it smelled like. This happened a week ago. He''ll try again tonight ( I hate talking in the third person ).


JP, oil level gauge comes all the way up in the same amount of time as always (He's had the car since 1980), and checked full on the stick. Druck pressure the same as oil pressure? I've seen this same sort of thing from water cooled cars with bad egr valves or stuck pcv valves. I thought white smoke was ignition, blue smoke oil

Any oil leaks? Sometimes when they leak the oil gets on the tops of the heat exchanger(s). As they slowly heat up, the oil starts to burn off.

Check the lower valve covers and the oil return tubes for leaks.

Check the oil pressure sender (Druck = german for pressure) in the engine compartment.
Could be a loose wire, or maybe the sender itself is toast...
Location of the sender is in the pic below (this is a 3.2, but it should be at the same spot on a 3.0)

Smoke on start up shouldn't be a concern, as long as it doesn't keep smoking for longer than a couple of seconds...

Can't help you on the stalling, but if the car has been sitting for such a long time

cheers,

Jeroen

No oil leaks.

Jeroen, No stalling. engine revs good and sounds good. I'll go look for myself tomorrow. Bro has three thumbs when it comes to motors. I got the smarts, he got the... oh, never mind. Thanks for the sending unit location. Gives me a place to start. Can I check the sender with my multi meter? Ohms factor , or just continuity?

Could be a loose wire, or the sender may have failed. On my '69 the sender failed overnight. I used a mechanical gauge to make sure I had pressure, turns out everything was ok, just a30 year old sender failed.

white smoke probably is just be water. The packing in the muffler absorbs moisture. the heat from the exhaust vaporizes it Viola white smoke..

Hmmm, white smoke. water vapor. been sitting for three months. lots of rain here lately.

Thanks for the suggestions guys. Anyone else? I'm listening to all advice.

I'm off to visit a very sweet lady tonight. check back in the morning, I hope.

I have a 1983 911SC Cab. that I put away in the winter, and I start the car every week or two weeks. It will usaully smoke on satrat up and I noticed this last time that it smoked a little more than usual. But not all of it out of the exhaust, I got under and found that the lower turbo valve covers had seeped out some oil and it landed on the heat exchangers, It did produce a lot of smoke but it did finally burn off.
Your car after mentioning alot of rain in the area could be condesation or water buildup in the muffler coming out. It could also be a rodent that was in the exhasut system that finally fried and poof.
Let us know what the outcome is .
CCLIN911SCCAMP

As long as there was no backfire ((BANG)) on startup then my guess is the same as what's been posted earlier. 911's often smoke a bit upon startup, especially if they've been sitting for a while. Oil leaks on the heat exchangers also make for a cloudy warmup. Check out that pressure gauge and be suspicious of anything that sounds like a misfire.

If there was a backfire at some point, and if your bro's car doesn't have a popoff valve, then there could be a cracked intake plenum which is an expensive fix.

Carl

If the oil level is (or was) over filled at all, it goes though the vent hose and into the air cleaner box. The oil could then be sucked into the intake and burned.

The oil temp must be at least 180 deg. to correctly check the oil level on the oil tank dipstick.

Water "smoke" is steam, it disapates quickly.
Oil smoke is a bluish white and it hangs around.

If a 911 engine sits around for a long time and the rings are lined up just right, oil will leak back into the sump and past the rings. Copius smoke, but right at startup.

The 3 minute deal leads me to suspect that oil is being blown into the air box and thus, into the intake stream.

It could be caused by any number of things.

Stuck/broken ring/s
causing excessive blow by.

Over full tank.

The oil pressure gauge worries me. Fluctuations in the readings could be a bad sender, connection, yada....of course it could also mean the pressure side of the system
isn't doing it's job while the scavenge side over fills the tank.

Pop off the aircleaner and see if there is oil present.....a little bit is normal.....alot is bad.

Is a 78 CIS?

I changed the oil pressure sender one time on an 82 SC. You can see it behind the air box but you cannot touch it.

Everyone told me to pull the engine, but I figured that it could not be as bad as removing the engine. 4 days and 10 skinned knuckles later it was done. Next time I will listen to "everyone".

Ok, I checked the car myself today, and here is the latest.
There is no external oil. everything is dry. Motor is clean, clean, clean. Smoke dissapates quickly. It comes from the tailpipe only. It's white and no smell or residue of oil.
He lives one mile from work, and drives it to work once every two months. He said he does start it and let it run for ten minutes once a week. I would love to tell him to "go drive the shit out of it like we used to", but the lack of indication of oil pressure says NO! How do I check the presssure sending unit?

Curt

Buy borrow or somehow get a mechanical pressure gauge, remove the exising pressure sender, and screw the mechanical one in, you may have to scrounge up some sort of adapters.

When the sender in my old 911 failed I checked the oil pressure with a mechanical gauge....It had 15psi at idle!!

I guess you could check the change in resistance of the sender using an ohmeter, but I don know what the range should be..

They do that all the time....they suck oil in from the oil tank and kill all the Mosquitos for miles around. Especially if hey sit awhile they will have oil shove past the rings when cold. Remember there is over 12 quarts of oil in that puppy.

I just browsed the factory shop manuals, but I couldn't find any data on how to measure the presure sender.

I did find that there is a seperate/independent switch for low/no oilpressure (which engages the warning light on the dash), so if there's no pressure, you'd be warned in time...
To check if that one works... it will light up before you start (ignition on), and then goes off just after you started the engine...

If you wanna check for blow-by or worn piston rings, open the oilfiller when the engine is running. If there's blow by, you'll see exhaust gasses escaping from the opened filler neck.

Like the others already explained... Oil smoke upon start up is normal. Because of the flat layout of the cilinders, oil seeps into the combustion chamber when the engine is turned off.
This little amount of oil is burned at start up (and therefore, the smoking shouldn't last long)

cheers,

Jeroen