OK ive been working on dsms for a while now, and i just recently got this 1990 gsx, what ive done so far stock rebuilt block 50,000miles, rebuilt and o-ringed head less than 1000miles, stock 14b.

Yesterday i did two things, i put on my 3in apexi (catless) turbo back exhaust from my previous dsm, and intalled my 3.5 gm maf and maft and new throttle body elbow.

I put the exhaust on first and started the car to check for leaks, everything looked good and there wasn't any smoke. Then i installed the MAF and MAFT and while calibrating the maft i noticed a steady fog of white smoke coming out of the muffler. So i obvious undid the last thing that i had done and hooked the stock maf back up, but it was still smoking. Did a compression check, all is good, coolant is full and green with no bubbles, oil is full and not milky. Started it this morning and still smoking, but it stops as soon as i start driving and wont smoke again untill I start it up again, which sounds like valve stem seals but literally the head was just completely rebuilt less than 1000 miles ago. Im leaning toward the stock 14b with unknown amount of miles, but the only other turbo i have to put on there is my holset HX-40 from my previous build, not neccisarilly ready to put that on with the stock bottom end and no tunning. Looking for any ideas, there was literally 0 smoke before the exhaust and maft install.....

Being that its white smoke, it sounds like you are burning coolant somewhere. you try a leak down test along with your compression test?

Have not done the leak down, the only thing i worked on that involves coolant was the throtle body when i put on the new elbow, anyone ever had the FIAV leak coolant into the TB?

I personally have not heard of it but try a leakdown if you get a chance to maybe pinpoint where the white smoke may be coming from.

Do a leakdown test like suggested, your problem could be with the head gasket.

iugrad92turbo said:

Do a leakdown test like suggested, your problem could be with the head gasket.

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That is exactly what I was thinking. I have seen strange things with little sign... Like my failed head gasket on my WRX. It showed no sign of a damaged head gasket but i spun a rod bearing due to that

Thanks i started it a lunch and it was no longer smoking, not sure what the problem was.... but yeah the head is oringed and held down with arp's I dont like changing head gaskets. Im just going to keep an eye on it hopefully it doesnt start smoking again.

Well chances are if it smoked once it will probably do it again until fixed, just one of those things head gasket no not fun. Turbo could be smoking, rule out things as you go but do the procedure, its a car things go wrong even when something may be new, i learned that new stuff, fresh stuff sometimes bad things happen im doinga full rebuild now so let us know what you find.

iugrad92turbo said:

Well chances are if it smoked once it will probably do it again until fixed, just one of those things head gasket no not fun. Turbo could be smoking, rule out things as you go but do the procedure, its a car things go wrong even when something may be new, i learned that new stuff, fresh stuff sometimes bad things happen im doinga full rebuild now so let us know what you find.

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yes... this... both friends and i have learned the hard way about new things gooing bad. just keep a close eye and look for oil and coolant mixing.

I would perform the leakdown test myself to check the shops work, if I were you.

I would pull the snorkle off the turbo to check for shaft play, since it takes ten minutes and the chance of a blown T25 is high.

Sounds like valve stem seals. And when doing your compression test was the engine fully warmed up. Did you try adding a cap of oil and performing a wet compression test to see if your numbers rise.

My 98 gst had 223k on the stock engine. It was burning oil too, not too bad but if it idled at a stop light or in a parking lot, it would puff smoke when I took off. I found oil in the intercooler pipes after the turbo, meaning the turbo was leaking oil into the intake. So I replaced that with a rebuilt 16g. Some of the smoking went away. I also took the head off and put in headstuds, new cometic headgasket and had the head resurfaced and new valve stem seals and no more smoke at all. Still running on the stock bottom end, rings, rods, pistons, bearings. No knock or not even any ticking from the lifters. Chances are its the turbo. Be careful, if the oil seal decides to completely go out, it will suck the oil out of the engine quicker than you can shut it off. If your running it hard.

i have a 1995 gst and i have white smoke coming out of the tail pipe, not all the time just when i really push it and it smells too , im not sure if im running rich or blown head gasket any suggestions on what it can be?

Black smoke fuel white smoke coolant.


Search it theres hundreds of threads on this subject

I agree with kbiger76. If it was bluish, it would be oil. In your case it is the white smoke indicating water/coolant being in your motor. I would check your headgasket first. Is your car low on coolant at times.

U said it smells, does it smell sweet? If so u likely have a BHG

Turbo could be blown, valve stem seals, head gasket, possible causes, sounds like more a turbo seal, are you oveheating, that would give the sign of a blown head gasket. When my hg blew several times it was overheating, lots of white smoke after driving, and then idling, it was my turbo. After many years of working on these things not too hard to work with, or fix.

my car does not over heat and it just lost coolant that i put on last week when i did a flush , it may be the turbo seal or many other things but im not sure how to figure it out exactly but do the process of elimination one thing at a time till i fix it . i will leave the head gasket for last since its the most work and expensive one..

Leakdown test is the best way to diagnose it I do believe. Is it boosting not boosting, loss of power? More information or we cant tell you anything

It does boost but has a delay I'm not sure if it needs to be tuned or a blown turbo, maybe a boost leak ? What exactly would the leak test tell me ? Wouldnt it tell me leaks all over the engine example piston rings also ?

Hectorb25 said:

It does boost but has a delay I'm not sure if it needs to be tuned or a blown turbo, maybe a boost leak ? What exactly would the leak test tell me ? Wouldn't it tell me leaks all over the engine example piston rings also ?

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According to you profile you have a stock 2g, so I dont think it you need a tune.

A blown turbo usually leaks oil rather than coolant, I think the CHRA would have to have a crack in it to leak coolant.

A "delay" in boost can because by different things. Do you mean you are not spooling or hitting boost until later RPMs? Having the t-25 you should have almost instant spool. Could be an exhaust leak somewhere before the turbo, manifold gasket, that could be causing this. Unlike the 1gs, 2g manifold are less prone to cracking to I would check the gaskets, manifold and turbo inlet.

It could also be your car retarding timing. This tends to feel like the the car is delaying.

The charged air in your system (air that the turbo produces that's positive pressure) in a closed system. There should be no air in or out from any other point besides the inlet and outlet (obvious exceptions like boost reference source). A boost leak test will tell you where the leak are in you system by creating positive pressure inside when the engine is off to allow you to hear/see where the air is leaking from. Common places would be the TB gaskets, injector seals, loose clamp on coupler, leaking BOV (2g stock BOV is notorious for leaking), Intake manifold gasket, anything that uses vacuum off the manifold could be leaking air out.

A boost leak test will only tell you if there are leaks within the turbo system, if done properly (closing the intake valves). The engine internals can be tested with a leak down test and/or compression test.

here is how to proper preform one:
http://www.dsmtuners.com/forums/art...-boost-leak-test-how-boostpro-net-tester.html

Good information agentorange313! I'd add rep points if I could...

Anyway, as mentioned above, white smoke is indicative of coolant leaking into the engine. My opinion, just do a compression test. It takes maybe 20 minutes and will tell you if your HG is toast. Low compression in adjacent cylinders will usually show you where the HG is damaged. This is very common.

TuRBoTaLooN said:

My opinion, just do a compression test. It takes maybe 20 minutes and will tell you if your HG is toast.

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A compression test won't tell you much about a head gasket issue, although low compression on adjacent cylinders is a symptom of one type of HG failure.

http://www.dsmtuners.com/forums/articles-engine-fuel/336535-do-you-have-blown-head-gasket.html

A much better approach is to do a leak-down test as kbiker76 mentioned.

http://www.dsmtuners.com/forums/articles-engine-fuel/338152-compression-leak-down-testing.html

calan said:

A compression test won't tell you much about a head gasket issue, although low compression on adjacent cylinders is a symptom of one type of HG failure.

http://www.dsmtuners.com/forums/articles-engine-fuel/336535-do-you-have-blown-head-gasket.html

A much better approach is to do a leak-down test as kbiker76 mentioned.

http://www.dsmtuners.com/forums/articles-engine-fuel/338152-compression-leak-down-testing.html

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I agree. A leak-down test is more specific and will yield better results in diagnosing the issue. However, the OP mentioned the white smoke out the exhaust (as in the title too), which according to your article (excellent write up btw!) is indicative of headgasket failure between cylinders allowing coolant to get in the combustion chamber and thus producing the white smoke. A compression test will show low compressio numbers at the adjacent cylinders. Granted, if that is the case, the leak can be elswhere in the combustion chamber (piston rings, valve seals, etc), but in the same sense, if it yields good compression numbers, it can be ruled out. I suggested this test because it is quick and easy to do with just a $20 compression test kit. I should have elaborated that low numbers should be followed up with a leak-down test to find the source of the leak.

But regardless, based on what I've read, if I had to guess I'd say he is experiencing a HG failure according to your #2 scenario in the article...a failure between cylinders allowing coolant into the combustion chamber.

EDIT

I also noticed he said the car doesn't overheat but loses coolant...

Hectorb25 said:

my car does not over heat and it just lost coolant that i put on last week when i did a flush , it may be the turbo seal or many other things but im not sure how to figure it out exactly but do the process of elimination one thing at a time till i fix it . i will leave the head gasket for last since its the most work and expensive one..

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Which further supports my theory.