What to do when your baby (my car) is sick? **(UPDATED 12/11)**

[dud]

I want to thank everyone who replied with comments (both constructive and not so much). A co-worker recommended a mech shop near where I live so I drove (just made it) the SC4 to their shop this morning for a full diagnostic. I just got a call ... and they have absolutely no idea what's wrong with it. They are stumped. These people work on higher-end cars such as Porsche, Mercedes, etc. and the only thing they can recommend is the Lexus dealership ... but they warned me they would be very expensive.

The saga continues ...






My Lexus 1993 SC400 is not feeling well and it's killing me. I probably need to have the car towed and checked out but I don't like anyone touching her.

My car has the 1UZ-FE V8 and has only 52,000 miles on her. The problem started about 6 months ago. Every once in a while I would pull up to a light and it would stall. Also, I would be travelling down the road and let off the gas and it would stall ... at 50 MPH!

Fast forward to this weekend ... I finally got the chance to work on her. I removed the IACV, a valve which allows air into the block and which can get clogged. Once removed I noticed that (for a 16 year old part) it looked clean and nearly pristine. I cleaned it out and put it back in. Once reinstalled I started her up and she ran perfectly! Game over, right? Wrong!

A day later the car will only start if you put the foot on the gas. If you let your foot off, it stalls in a second. If you punch the gas to 2000 RPM a white smoke comes out the back ... and the exhaust smells really bad.

I am an avid DIY'er and have tried EVERYTHING I can think of. I have cleaned the IACV, I checked the MAF with my meter and it checks out. I pulled the whole air intake up to the throttle body and it is near pristine.

I know this is an air-fuel mixture problem at idle but cannotput my finger on the problem. Anyone have any ideas?

Thanks ...

 

[Bignate603]

White smoke usually indicates a head gasket problem. Have you been going through coolant? Do you see air bubbles in the coolant tank.

 

[jhu]

I'm confused. How did my baby become your car? Give it back!

 

[JulesMaximus]

White smoke usually indicates a head gasket problem. Have you been going through coolant? Do you see air bubbles in the coolant tank.

QFT. I bet you're looking at a blown head gasket which means removing the intake manifold and one of the cylinder heads...parts aren't expensive but there's a lot of labor involved.

 

[canadageek]

I wouldn't agree with a faulty headgasket. a headgasket failure would show consistent symptoms, and this sounds like it comes and goes. I'd take another look at the IAC, seeing as how things got better, then worse after you cleaned it. pull your codes using this http://www.troublecodes.net/Lexus/ then get back to us.

few more Qs:
any oil going missing?
is there emulsified oil in the coolant/water in the oil? (yogurt)
what does this smoke smell like? gas? sweet, like coolant? like burning oil?

 

[fleabag]

Did you do the trunk wire thingy? I can't remember if that is only an LS400 problem but the SC400 and LS400 do share the same engines.. You should check out lexusownerslcub.com or clublexus.com for more info on your car as those forums know a bit more about the car than this forum. This forum is closer to a chilton's manual while those forums would be like a full service manual...

 

[Vette73]

Did you do the trunk wire thingy? I can't remember if that is only an LS400 problem but the SC400 and LS400 do share the same engines.. You should check out lexusownerslcub.com or clublexus.com for more info on your car as those forums know a bit more about the car than this forum. This forum is closer to a chilton's manual while those forums would be like a full service manual...

Yea that forum is running on MAX PRESSURE~!!!

This forum barly meets the inside door jam pressure.

 

[angry hampster]

Could be a horrific vacuum leak.

 

[fleabag]

Yea that forum is running on MAX PRESSURE~!!!

This forum barly meets the inside door jam pressure.

Phonetically that's "barley" so I'm just going to assume you miss the beer icon..

 

[AdamK47]

Is this the car that was babied and garaged by the previous owner only to sit and depreciate for you to snatch up at a great price?

 

[dud]

I wouldn't agree with a faulty headgasket. a headgasket failure would show consistent symptoms, and this sounds like it comes and goes. I'd take another look at the IAC, seeing as how things got better, then worse after you cleaned it. pull your codes using this http://www.troublecodes.net/Lexus/ then get back to us.

few more Qs:
any oil going missing?
is there emulsified oil in the coolant/water in the oil? (yogurt)
what does this smoke smell like? gas? sweet, like coolant? like burning oil?

No oil is missing ...
No oil in the coolant ...
The exhaust smells like it is saturated with unburned chemicals.


I am beginning to think the problem is the ECU. If I had a spare I would change it out to see what would happen. A new ECU is about $250.

 

[derrick2237]

No check engine light? Check for the trouble codes. Weird exhaust smells could be bad catalytic converter.

Also check your spark plugs, they can tell you alot depending on the color/patterns on them.

 

[iamwiz82]

Is this the car that was babied and garaged by the previous owner only to sit and depreciate for you to snatch up at a great price?

You're the dummy for paying for depreciation, mang. He just gets the ladies to droll over his 16 year old car while yours sits in your garage. ^_^

 

[AdamK47]

You don't know that. There are plenty of hot women going into the garage and drooling over them. I have to tell them to leave because they keep ruining the clean paint.

 

[boardsportsrule]

i would go back to the ICV...clean it with carb cleaner, but leave it lubed with WD-40 or similiar...too clean=metal-on-metal grabbing...

 

[fleabag]

i would go back to the ICV...clean it with carb cleaner, but leave it lubed with WD-40 or similiar...too clean=metal-on-metal grabbing...

Worst advice I have EVER read on a forum... Do NOT use WD-40 to "lube it up".. D: Just go to the lexus forum and ask those guys because the people here haven't a damned clue about these cars as these problems are usually more out of the ordinary and aren't what on would normally expect. i.e. these cars are "unique".

 

[alfa147x]

I had a problem like this for my '94 altima normally white smoke = head gasket problem
but in this case im almost sure that your white smoke is straight gas coming out your exhaust... hold a cloth and let it absorb some of the white smoke and smell it... i ended up selling my altima and never did get it fixed...

 

[SpatiallyAware]

Worst advice I have EVER read on a forum... Do NOT use WD-40 to "lube it up".. D: Just go to the lexus forum and ask those guys because the people here haven't a damned clue about these cars as these problems are usually more out of the ordinary and aren't what on would normally expect. i.e. these cars are "unique".

lol no, they aren't.


Although I agree with no wd40 on an IACV. Personally I would try contact cleaner first, then maybe maf safe TB cleaner

 

[Pacfanweb]

No oil is missing ...
No oil in the coolant ...
The exhaust smells like it is saturated with unburned chemicals.


I am beginning to think the problem is the ECU. If I had a spare I would change it out to see what would happen. A new ECU is about $250.

Or you could take it to someone who knows what they're doing and get a proper diagnosis.

 

[Pacfanweb]

Worst advice I have EVER read on a forum... Do NOT use WD-40 to "lube it up".. D: Just go to the lexus forum and ask those guys because the people here haven't a damned clue about these cars as these problems are usually more out of the ordinary and aren't what on would normally expect. i.e. these cars are "unique".

No they're not. They're fancy Toyotas...no more, no less.

 

[JulesMaximus]

No they're not. They're fancy Toyotas...no more, no less.

Agreed. It's a great engine but there really isn't anything overly special or unique about it.

I'm curious to see what was wrong with it though. Hopefully, the OP will update us.

The 4.0 L (3,968 cc/242.1 cu in) all-alloy 1UZ-FE debuted in 1989 in the first generation Lexus LS 400/Toyota Celsior and the engine was progressively released across a number of other models in the Toyota/Lexus range. The engine is oversquare by design, with a bore size of 87.5 mm (3.44 in) and stroke of 82.5 mm (3.25 in).[1] It has proved to be a strong, reliable and smooth powerplant with features such as 6-bolt main bearings and belt-driven quad-camshafts. The connecting rods and crankshaft are constructed of steel. The pistons are hypereutectic.

It's resemblance to a race engine platform (6 bolt cross mains and over square configuration) was confirmed in 2007 by David Currier, vice president of TRD USA in an interview with http://www.v-eight.com stating that the 1UZ platform was based on CART/IRL engine design. It was planned to be used on GT500 vehicles, however its subsequent use in the Daytona Prototype use was not planned.

In its standard, original trim with 10:1 compression, power output is 191 kW (256 hp), torque of 353 N·m (260 ft·lbf).[1]

1UZ-FEThe engine was slightly revised in 1995 with lighter connecting rods and pistons and an increased compression ratio to 10.4:1 resulting in peak power of 195 kW (261 hp) and torque of 363 N·m (268 lb·ft).

In 1997, Toyota's VVT-i variable valve timing technology was introduced along with a further CR increase to 10.5:1,[1] bumping power and torque to 216 kW (290 hp) and 407 N·m (300 ft·lbf). In the GS400 application, output was rated at 300 hp and 310 ft-lb of torque.

The 1UZ-FE was voted to the Ward's 10 Best Engines list for 1998 through 2000

 

[alfa147x]

Check your egr valve

 

[fleabag]

Agreed. It's a great engine but there really isn't anything overly special or unique about it.

I'm curious to see what was wrong with it though. Hopefully, the OP will update us.

You can tell me that when you do your own work on your LS400 or any other Lexus for that matter. "Fancy Toyota or not" these vehicles have to meet a lot of requirements in order to be sold as they are. Working on an LS400 is no Corolla by any means and clearly you're not aware of the things that make these cars malfunction because otherwise you wouldn't be saying what you're saying. If we were talking about an ES350, then I'd agree it's a fancy Camry but the LS has a lot more stuff that you'll never see which makes working on them that much more difficult. The engine isn't the problem, it's all the associated crap with the bad capacitors and other electrical anomalies that is what makes it stop functioning properly. In case you didn't pickup on it, the LS and the SC are mostly the same vehicle in terms of expense and complexity, the difference being the SC is an LS400 "coupe". Oh and don't argue with me about how the SC isn't based on the LS400 body and all that crap because I already know that.

 

[Bignate603]

You can tell me that when you do your own work on your LS400 or any other Lexus for that matter. "Fancy Toyota or not" these vehicles have to meet a lot of requirements in order to be sold as they are. Working on an LS400 is no Corolla by any means and clearly you're not aware of the things that make these cars malfunction because otherwise you wouldn't be saying what you're saying. If we were talking about an ES350, then I'd agree it's a fancy Camry but the LS has a lot more stuff that you'll never see which makes working on them that much more difficult. The engine isn't the problem, it's all the associated crap with the bad capacitors and other electrical anomalies that is what makes it stop functioning properly. In case you didn't pickup on it, the LS and the SC are mostly the same vehicle in terms of expense and complexity, the difference being the SC is an LS400 "coupe". Oh and don't argue with me about how the SC isn't based on the LS400 body and all that crap because I already know that.

So it has lots of electronics that go wrong, just like any luxury car from the same time period?

 

[videogames101]

You can tell me that when you do your own work on your LS400 or any other Lexus for that matter. "Fancy Toyota or not" these vehicles have to meet a lot of requirements in order to be sold as they are. Working on an LS400 is no Corolla by any means and clearly you're not aware of the things that make these cars malfunction because otherwise you wouldn't be saying what you're saying. If we were talking about an ES350, then I'd agree it's a fancy Camry but the LS has a lot more stuff that you'll never see which makes working on them that much more difficult. The engine isn't the problem, it's all the associated crap with the bad capacitors and other electrical anomalies that is what makes it stop functioning properly. In case you didn't pickup on it, the LS and the SC are mostly the same vehicle in terms of expense and complexity, the difference being the SC is an LS400 "coupe". Oh and don't argue with me about how the SC isn't based on the LS400 body and all that crap because I already know that.

So, you're saying that

"If you punch the gas to 2000 RPM a white smoke comes out the back ... and the exhaust smells really bad."

Is caused by electronics malfunction, and that it wouldn't present itself as a problem in a Camry?