Do I have a bad Turbo or boost leak or both???

[1996GSTurbo]

I have a 1996 GST with 120,000 miles on it with a stock turbo. For the past couple of weeks my car has been going from 700rpm-500rpm around there, also i get white smoke coming from the exhaust when i first start it in the morning or whenever its been sitting for awhile then it goes away once it gets warm (seems to be worse when its cold). Now today when i was coming home from work i noticed a small amout of smoke coming from under the hood and from the exhaust when i was waiting at the light and i was not getting any boost until i was going 3500 rpm but just over the first bar on the stock boost gauge and the car was sluggish like it was a RS. I havent had a chance to look at it yet but i wanted some advice before i dig in. other then thatthe car still runs and sounds fine just sluggish. The spark plug only have 20,000 miles on it (ngk iridiums) just did an oil change 200 miles ago (mobile 1) didnt have coolant in it just dirty. I changed my timing belt and water pump 200 miles ago no oil in coolant car ran great after water pump and timing belt were installed. i couldnt find an oil leak anywhere. i hope this was descriptive enough.

 

[1996GSTurbo]

ohhh and one more thing the head gasket was replaced 15000 miles ago havent had a leak or problem with it since

 

[Redwan]

I don't think its your turbo, could be vacuum leak, you might be having a bad head gasket that is allowing coolant into one of your cylinders..white smoke means coolant, that would explain the lazy performance. Do a compression test to see what your numbers are..and do a boost leak test and go from there see what happens.

 

[1996GSTurbo]

ok well today i finally had a chance to look at my car and when i turned it on to see if i had an ovious boost leak i noticed i didnt have any white smoke coming from the exhaust like when i start it up in the early morning and late nights. (that when it would smoke when it was cold out). but it smells like gas out of the exhaust (it always smells like gas out of the exhaust) and i still dont have boost. would a boost leak cause a gas smell out of the exhaust because it not getting the air it needs or might it be a spark plug thing???? i just replaced them like 30000 miles ago and they are the ngk iridiums. i thought they lasted longer then that. plus my air filter is really bad so im going to change that any othere suggestions???

 

[SpyderDSM]

if you aren't experiencing misfires i think your plugs are fine. i think you NEED to do a boost leak test before you can decide anything. white smoke could mean awful things for your turbo but if you can check the shaft play i would do that as well.

1) boost leak test
report back

 

[SpyderDSM]

ok well today i finally had a chance to look at my car and when i turned it on to see if i had an ovious boost leak i noticed i didnt have any white smoke coming from the exhaust like when i start it up in the early morning and late nights. (that when it would smoke when it was cold out). but it smells like gas out of the exhaust (it always smells like gas out of the exhaust) and i still dont have boost. would a boost leak cause a gas smell out of the exhaust because it not getting the air it needs or might it be a spark plug thing???? i just replaced them like 30000 miles ago and they are the ngk iridiums. i thought they lasted longer then that. plus my air filter is really bad so im going to change that any othere suggestions???

oh and the gas thing happens occasionally to me as well. It seems to happen on start up, a boost leak shouldnt be causing this.

 

[90on35psi]

Do a compression test to check the head gasket. If thats solid, check the turbo for shaft play. Check the oil level too to make sure you haven't got milky oil on the dipstick. It's probably running sluggish because you've got iridium plugs in there. They foul out pretty easily. Stick to the regular NGK's

 

[kenamond]

If the smoke is truly white, that indicates coolant, which is bad. If it's a bit blue, that's oil.

As was mentioned, check the turbo for excessive shaft play. Pull the intake pipe off the turbo compressor inlet (cool motor), grab the compressor wheel nut and see if there's any in/out or side/side play. Should be no in/out and only a little side/side. Spin the wheel; it should spin freely.

Smoke on startup is often a sign of worn valve stem seals.

I also agree with doing a compression test. If you do one, report the numbers. If you have low compression, do a wet test.

Also, do a boost leak test. It's always a good idea.

For $8, you can get a set of NGK BPR6ES plugs. Those are the plugs that work for EVERYONE. Folks have had problems with iridium plugs...and they're a lot more expensive. Gap the plugs to 0.028". If you're running above 17psi boost, go with 7ES plugs. If you're high boost, you probably know what plugs you need.

 

[knochgoon24]

I'd check to make sure your don't have any pre-turbo exhaust leaks. Check to make sure your exhaust manifold to turbo bolts are tight and that the manifold and turbine housing aren't cracked.

And try to run NGK BPR6ES plugs gapped to .028". They seem to be the best spark plug for our cars.

AND preform a boost leak test. Just do a search on this site and make a boost leak tester to pressure test your IC piping. You'll probably find a few. The most notorious are throttle shaft seals, BISS o-ring, and injector seals, along with the usual IC couplers.

 

[1996GSTurbo]

thanks guys i will do a test and let you know

 

[TheAButton]

Well when you start any car up when its cool out its gonna smoke because of condensation in the exhaust, but when its warm out and the car is warmed up and it still is smoking a lot then you have a problem. Something I'd would look into is if who ever put the head gasket on, did they reused the head studs. Because if you or the person didn't replace the oem headstuds, that could be your problem all together. Because the stock head studs can stretch which will cause a small head gasket leak. If this is the case you'll just need to buy some ARP head studs, and maybe a new gasket (if its okay when you look at it). Thats how I bought my last car, the guy thought he blew out his gasket, but when he rebuilt the motor he reused the same ones and ended up selling his car to cause of it. Hope that helps you out.

 

[1996GSTurbo]

i think thats all it is because it doesnt smoke when it warm out and like i said if its cold out it only smokes alittle bit until it warms up. so far what i read that doesnt seem like a blown head gasket or leak and it smells like gas and not coolant. i just cant find the damn leak