IEATV8s

hey guys. I'm sorta new to the porsche scene seeing as though I purchased my 951 all of about a month ago now. Anyways, my car was running fine earlier today until I came to a stop sign right off of the freeway. It hesitated a little and sounded like a lawn mower at lower Rpms (below 2000) and blew a ton of white smoke ot the back. However after getting above about 2000 rpms the smoke went away and the car sounded normal. Luckily I was right around the corner from my mechanic and I dropped the car off to him to look and see. This was all of about 1 1/2 hours ago so I don't suspect to here anything from him anytime real soon. I did a little search here on the forums for white smoke and found out that it could possibly be the turbo seal or something to that extent. Anybody have any ideas on what this could be?

Thanks,

Ben

***EDIT*** also, I had just recieved the car back from the dynoshop earlier today where they changed out the spark-plugs and re-did my A/F seeing as though it was too rich. Perhaps they leaned it out too much?

mark944turbo

headgasket , check compression

special tool

Ben - yeah, perhaps man. How did the proffesionals adjust the afr of your 951?
What type of wideband do they use? What static fuel pressure setting? If they dynoed the car - tell them that you will need the wideband trace from all runs. These are questions you need to ask them first.

Porsche-O-Phile

Your car has elected a new pope.

Peckster

Who, that german guy Ratsinger?

Probably HG, a compression test might not reveal it.

mark944turbo

Make sure you leave the throttle open while you do it. The compression test i mean.

hosrom_951

And the engine at normal operating temperature as well

IEATV8s

I was thinking headgasket as well. Oh well, I think the car was still on its original so perhaps I was tempting fate a little too much. As for wht type of wideband they used...Im not sure. I know that they tuned it on the dyno and I looked at the A/F chart they gave me and they were all in the 11-12 range. I also noticed that at idle the car had a A/f of about 16 or so (i have a wideband meter). Do you think that this could be a result of a bad tune, or just an old head gasket past its prime? Thanks for all the input though.

Ben

951gashog

is there any oil in the coolant, or coolant in the oil?? (Moisture all over bottom of Oil filler cap??)

badass951

As mentioned by others, head gasket. I say run a leakdown test instead of a compression test as this will clarify the problem more effectively.

Epic2112

IEATV8s

I didn't have time to check for this unfortunately. I will find out tomorrow hopefully the extent of the damages from Matt, (my friend/ mechanic). Perhaps this is a good time to upgrade the engine a little more...?

-Ben

special tool

Those afr's are like mine - so looks like they are off the hook. Pushing the original gasket probably caused it.

IEATV8s

lol, cool. If all it is is a blown head gasket then I can deal with that. Shouldn't be too bad. Thanks everybody.

-Ben

Bill

Just for information purposes, blown head gaskets are not always caused by just a lean condition.

A motor that is overheated can cause a failure (bad radiator, water pump, water hose, radiator cap). Improper head torque and a lifting head can cause a failure (stretching head studs, too much boost, block threads failing). A warped head/block deck (from overheated motor, see above), thus poor sealing surfaces. The head gasket itself could have a weak area from manufacturing and fail later than sooner. Of course, the ever popular lean air/fuel mixture.

And....white smoke from the exhaust pipe. It is from water entering the combustion chamber, but it is not always from a head gasket. Could be a cracked head or cracked block. Could come from water entering the intake system.

Check everything. Unless you want to possibly replace good parts. Or possibly miss the bad parts. And of couse, do the repair again.

A lean AFR burns very hot. If this is the cause the metal ring on the head gasket will be "melted or burned" through. The spark plug tips will be white.

If the head is lifting or too much boost, the metal ring will be "oval" or pushed out of round.

A warped surface. A water trail (rust) can be seen on the metal ring of the gasket. Or an ovaled seal ring.

The moral of the story......do not just jump to the easy conclusion.