Ok, weirdest thing happend, not sure if it's bad, but sure it couldn't be good

i was accelerating from a stop and i was in the top of 2nd gear at 5,900 rpm's and i hear a loud deep pop and i look into my driver side mirror and i see a thick cloud of white smoke!!

at first i thought i blew out my tire so i slowly pull into the gas station i was right accross from and i get out and to my suprise the tire was fine..... so i stepped on the gas pedal a bit to get into 3,000 rpms and white smoke is coming out of my exhaust tip and around the muffler itself.....

fortunately it doesn't smoke now, this was about an hour ago

Any ideas of what could have happend..

the muffler itself is original

 

PS: this is a 79 928

 

White smoke suggests water, but from where? I had a 944 that had a leaking head gasket that caused the same thing when coolant hit the cat, but those symptoms did not resolve as you describe but kept occuring.Good luck. Ed M

 

The pop could have been the sound of something going bad in the motor.
And the smoke was a symptom.

I do not know anything in the exhaust that would cause a cloud of white smoke.

Burning oil or water will do it.

So I'd check out the engine pretty well, before driving it any more.

It may save you from it being a simple repair, versus a very expensive one...

 

But the thing was this was all of a sudden!

first it wasn't then it was

if you're suggesting watter then couldn't it have been a gradual change and it stopped smoking when i let the rpm's drop (this is from decceleration imediately after the pop noise)

 

Appears to be a bad/removed/disabled decelertion valve, bad timing or both. This allows the ignition to retard too quickly, causing incomplete ignition before the exhaust valve opens. Needless to say, this can be hard on the valves, cat and other exhaust components.

Dennis

 

sorry, i should've been more clear, the smoke died down as i decelerated

smoke started after a pop at the top of 2nd gear 5,900-6k RPM's

smoke comes not only out of muffler tips but around the muffler itself

i think i covered all bases

 

My EuroS did this at the same time an exhaust hanger broke causing the tailpipe to hit the bumper cover. The giant smoke cloud that engulfed the car and sudden loss of power scared the crap out of me. After having the local FD put out the plastic fire, we noticed that the entire exhaust from the cat back was white and flaking. I haven't had a chance to do too much diagnosis since I took the timing belt off soon after and the engine is still in pieces. The concensus seems to be that my cat is clogged and full of unburned gas. When mine was smoking (it had stopped before the T-belt came off, but I was only taking short trips around the block so it wouldn't heat up too much), it was coming out somewhere under the air box and out of the end of the exhaust.

Does your exhaust pipe look like it has been heated up a lot? Do you have a loss of power? Maybe your cat or muffler is clogged.

 

i'm actually thinking about ordering the cat bypass test pipe from 928 specialists and a set of headers from devek or 928 intl to fix this problem, since my car is a 79 i don't need emmissions test or a cat..

i'm also looking for a nicer sounding muffler, any ideas??