JohnEd

iTrader: (1)

Got some news from my Lex service rep. about oil smoke out the ex at startup. Seems the "up-idle switch" that is located on the power steering output perforates internally and the vacium line connected to it sucks pwr str fluid into the intake. Soooooo, you think you have valve seal or ring problems and the pwr str fluid is just leaking somewhere. And, you are right, sorta.

Sorry if this has been hashed before and is old hat, I just get so excited and everything. Imagine, if this saves just one dude from yanking his heads to redo the seals? Well, my work here would be done.

Lex said it is a common problem.

John

XxSC400xX

iTrader: (1)

Does it smoke EVERY time you start it up? Occasionally I used to get some smoke on startup on really cold mornings. From what I understand it is the valve stem seals leaking a bit of oil into the cylinder head when they shrink due to the temp. It only happened like twice. Now I keep my car in the garage.

JohnEd

iTrader: (1)

XX,

If the up-idle valve is your problem you should see some loss of power steering fluid. The oil only migrates in high vacium condition. When you shut down your engine it has usually idled for a minute before hand. At start up the engine idles a while befor you start out. The first time you get into the throttle very deep you get a puf of smoke. It will seep oil into the intake all day but because you are driving you never accumulate the oil in the intake manifold. At the bottom of a long coasting hill you get a serious puff when you first get on the throttle.

This is exactly the same symptom as leaking intake valve seals. The clue is where you are using oil...engine oil or pwr str oil. I wsa using more than a quart of atf a week in a Ford way back. It turned out the vac modulator switch was leaking atf back up to the intake manifold. The first time you encounter this it is a real mystery. Lex said "I stock this up-idle valve because we encounter so many bad ones." Hint!

Hope this helps.

John

XxSC400xX

iTrader: (1)

No, it doesn't smoke while driving or use power steering fluid (I keep a close eye on it to make sure it's not leaking onto the alternator) or any noticeable amount of engine oil. I'm sure it was just a fluke due to an extra cold morning.

Thanks for the info. Something to keep in mind as Lexus says it's a common problem.

tkafam1

Hey guys, I have the same thing on occasion. It's usually a bluish white smoke that doesn't last very long. I had the dealership check the powersteering pump for leaks and they said it was fine (this was about 2.5 years ago) I just got the car back this morning and the service shop changed the powersteering fluid because it was pretty old. They said it didn't appear to have any fluid missing. So I guess whatever is creating the occasion smoke isn't power steering fluid. This has been going on since I got the car and so far it hasn't caused any other problems, other than an occasional increased heart rate. I would love to know what causes it, but I'm glad to know its a common problem.

MJHSC400

I know this was a commonplace thing on the LS, but was not aware the SC had the same inherent problem--

Mine doesn't seem to lose any fluid, but maybe I'm not checking it close enough..

I'll watch it closer--- I also hear the part is cheap too--

94SC4

John, many many thanks for this info. I was about to go to the Lexus dealer with the white puff of smoke issue and I'm sure they would have suggested valve stem seals. After reading your post, I looked up the info in the service manual, disconnected and then plugged the vacuum lines, and have driven it for several weeks. No smoke! The p/s pump is leaking just a bit so I thought the fluid loss in the reservior was a result of the p/s pump, which is only partially true. The vacuum valve only cost $100 verse, I'm sure, a couple thousand at Lexus for stem seals. Many thanks again - this forum and your info is a huge money savor.

over40driv

Anybody got a picture of the idle step up valve with a pointer to it?

over40driv

One time, before I got my new cat. conv. and mufflers I started the car up the morning after a little high rpm romp, and the car had a whitish-blue smoke for about 15-20 secs. Normally a cold start-up is crystal clear.

94SC4

The Idle Up Valve screws directly into the pressure side of the hose at the power steering pump. You can only see it from the engine compartment using an inspection mirror or you'll need to take off the under tray and look for it from below. The valve has two vacuum hoses coming off from it. Basically, look for any device attached directly to the pressure side hose at the pump. I had to remove the pump to get to it and replace it.

b1ackhawk

ill have to check this out. A little smoke on cold starts than goes away immediately.

DasBach

iTrader: (7)

I get that little puff of smoke too! I also had to refill my power steering last week

mr2tosc4

iTrader: (1)

Resurrecting this thread, I'm having similar issues right now. From what I've read, you can either: 1. Buy an Idle up valve -- or -- 2. Try OLT's $3 fix and get rid of the vacuum lines. Am I missing something else?