Lex*Toy

99 SC400 VVT-i
93,000 Miles

Oil: Mobil-1 5W-30


I was stepping on my car pretty hard today for about an hour or so, until I noticed a light haze of white smoke in my rearview mirror


Not good.

Changed oil 2 months ago, where I know my SRT ECU, headers, exhaust system has me running rich. This is a fact, since I barely didnt pass emissions 4 times!

What could be causing the smoke?

And most importantly, what to do about it that doesn't involve rebuilding and leak-down tests since I dont want to think about rebuilding on the motor.

BTW- Spark plugs were changed 2 months ago as well


So what does the Doctor prescribe?

VJ RC51

From all my experence with white smoke on a 2J, its fuel. When its smoking, take a lighter to it and stand back hahahhhhaha, i almost caught my arm on fire doing that. Bad ecu in my case.

It would be super super rare for you to blow a headgasket n/a.

SupraCoup3

two things:

searching would tell you what white smoke is, and second: this should be in the engine/tranny section.


White smoke is water or coolant in the exhaust. How much white smoke are you seeing? If you're laying down a pretty good cloud, I'd be inclined to think BHG (which is rarely heard of on the 1UZ)

and FYI:
Blue smoke is oil, black is unburnt gas (you'll only see this if you're running pig-rich)

Lex*Toy

Blown headgasket? On a 1UZFE?

Second opinion?

DaveGS4

iTrader: (2)

I found this information and posted it on a prior thread a few months ago.... may be useful:

----------------------------------------------------------------------------------------------------------------

Exactly what color is the smoke? Here's a good diagnostic FAQ I found with a quick google search...

From http://www.salemboysauto.com/faqs/faq-38.htm:

Black, blue, white or grey smoke from the tailpipe!

--------------------------------------------------------------------------------

Black smoke is raw gasoline burning. A rich condition can be the cause by a heavy or mis adjusted float, a choke stuck shut, a bad oxygen sensor, a bad map sensor, a bad fuel pressure regulator, a plugged up air filter or a bad injector. Typically, if you only get black smoke first thing in the morning, it has to do with the choke or the fuel enrichment portion of your fuel injection system. If you get black smoke all the time, get it fixed NOW. If you don’t, you run the risk of wiping out the catalytic convertor and doubling your repair bill.

Blue smoke is oil burning. The tailpipe will either smoke all the time or just once, first thing in the morning. If you get blue smoke all the time, that is a sign of impeding doom. That is the first sign of the beginning of the end. Broken rings, bad pistons, damaged cylinder walls, all high dollar items.

On the other hand, if all you get is a puff or two first thing in the morning and never again throughout the day, then your problem is probably bad value guides or value guide seals. It will cost between $350-800 to replace the seals, $750-1,500 to replace the guides and seals. I always tell my customers, wait until you begin to see other symptoms of this oil usage. Wait until you start fouling plugs, wait until the oil consumption is greater than one quart every 1,000 miles. And never assume that seals alone will totally fix this problem, if the engine has 100k miles plus.

Grey smoke can really be black or blue. You can usually tell which is it by the smell or by matching other symptoms you have to the color of the smoke is easier. Others will say blue is blue and all other is really grey to black and I would agree.

White smoke is either the transmission shift modulator is bad and allowing the engine to suck and burn transmission fluid (repair costs under $100) or it’s really, really bad. White smoke could also be coolant or antifreeze that is either leaking, or being forced into the combustion chambers and being burned. The exhaust will look wet and have a sweet smell to it. A bad head gasket (75% of the time), a broken head (15% of the time) or a broken cylinder wall (10% of the time) will be the reason your engine is burning coolant or antifreeze. The repairs start at $400 and go to $4,000.

DriftGirl

iTrader: (6)

Do all the normal 'headgasket checks'. (milky oil,radiator pressure test,etc)

or hold your hand an inch away from the exhaust while its smoking. Just hold it there till it gets too hot, then look for water in your palm

These engines should last forever....with simple bolt on mods. Ive gone thru a few but thats with FI






Just do the leakdown test

VJ RC51

My engine white smoked from fuel. The car ran like crap. The white smoke was vaporized fuel that was UNBURNT!!! I was getting about 5mpg and the car ran rougher then crap. You could light the exhaust on fire into a big fireball hahahaha.

Lex*Toy

I did hit the rev limiter pretty hard in 3rd, for about 5-6 seconds while paying attiention in bend not to "make nice" with the concrete barrier.

How can I check ths? If the transmission shift modeular is bad? Can I replace it?

Lex*Toy

Smoke did not have a "sweet" smell, but one that contained oil. Transmission fluid? Or ECU bupped up fuel usage for "higher than average" driving, without decreasing from too-fast-to-normal driving.

Smoke lingered and did not care about on or off acceleration. Constant until I pulled over and let car cool down for 5 minutes.

Questionable. Seems like I might have to do a leak-down.

Water level is exactly where I normally keep it 1.5 inches over full.

Probabilty of issue?

Bosco

If not white, blue, grey, or black, what color is the smoke supposed to be?

Lex*Toy

White smoke for water issues, but there is a thin line between white and gray in your rearview mirror on a sunny day.

The jury is still deliberating before I muster the nerve to purchase a leak down kit.

Project300

Emerald knows the 1UZ and a leakdown test is the best place to start, since it isn't very hard to do and tells you if the head gaskets are at fault. Either way, you will not fix this by just changing the spark plugs or the oil. Sounds like it's time to turn some serious wrenches on that 1UZ.

nasc300

My white smoke problem with an sc300
https://www.clublexus.com/forums/sho...ht=white+smoke


The advise I got below was completely wrong in my case.
https://www.clublexus.com/forums/sho...ht=white+smoke

SupraCoup3

If you don't give all the pertinant information, (like being NA-T, which means some wire splicing hence the possiblity of a fried ECU)

How do you expect people thousands of miles away from you to accurately diagnose white smoke coming out of your unbeknownsts to us NA-T'd SC300?

People too often mistake advice on the internet as the word... it's not, it's simply advice. A good place to start. The number of factors involved in white smoke means that we can merely tell someone why it most often happens, and what causes the smoke to be white.

If you want an absolute answer, pay a team of mechanics to break down your engine and check ever last tolerance.

If you want free advice, post up here.

nasc300

Read again. And pay attention this time
The car was and still is NA.
Stock as hell when I asked for advice not even a ricer sticker.
No ECU or wire tampering at all, thus you have no point to make.
I "plan" on going NA-t some time soon.


This is exactly my point.
Everyone jumps to conclusions. Yes white smoke in most cases is caused by a BHG. But not always. Like I said the advice (and not the WORD) I got was completely wrong in my case. Now that is a fact.