90LS400Lexus

I was under the impression dirty throttle body is a solution for erratic idling due to the throttle plate not being able to seal closed fully and thereby creating air leaks which work against the action of the IACV. As such I don't understand what it would do at open throttle positions such as 2-3K RPM. Are you sure you're not ascribing too much benefit to a throttle body cleaning? Definitely a fix for idle issues, but I’m not so sure about the other.

I am really not sure. All I know is that on take off, when I hit about 1500 rpms, I would have a "dead" spot and it was not even. Also, when I would be going 35-50 mph and it was in overdrive, if I was changing "grades" of the road, the car would lunge, as if there was slack somewhere. Well, all of that hooplah is completely gone after the throttle body cleaning. I am impressed. I didnt get to enjoy it this evening, because we are in the middle of a snow storm! I left my Lexus setting at the parking lot at work! My uncle brought me home in his 4wd. We have 5 inches of snow here at my house, but some areas have much more... roads are ALL snow covered, numerous power outages, accidents, etc. Its bad.

We are not really used to alot of snow, so its made a mess of things here.

Definitely... thats your problem. You will be amazed!

I love the power steering systems on the gen 1 LS400s.

I love my car, but the PS systems are crappy and complex. They are good when they are working, but how many people have not had issues? If they havent, they will soon! ;)

Sorry, I dont know whats going on with your PS system... cant even figure out my problem of occasionally stiffer steering. I was able though to stop the leak. :)

Good luck.

They probably won't know what to do at AZ or AA.

You can do it yourself with this --> http://www.lexls.com/tutorials/intro/codereading.html

Thank you very much for that link! Seems very simple. If (or when) it comes back on, I will know what to do!

Well, I had already disconnected the battery to reset it and it didnt come back on just by starting it, but I am sure it will come on again. I guess I had cleared the code. I wish I had of waited. So strange it decided to do this shortly after I had the throttle body cleaned. Maybe he left a connection loose, or there is a vacuum leak at one of those vacuum lines he had disconnected in the process.

Update - ran the code and its "71" EGR system malfunction. It did not do this until I had the throttle body cleaned

On my drive home from work this evening when on the highway, my check engine light illuminated! It stayed on steady. The light stayed on, but the car is running better than ever now. To recap, I had the throttle body cleaned two days ago and the car runs so much better. Not sure if the issue is connected or not. I did disconnect the battery, restarted and it didnt come back on. I am wondering if it was just needed to be reset or something?

If it comes back on, can somewhere like Advance or Autozone read the codes on these cars?

Naturally this would happen three days before I likely had it sold! <_<

I have a 97 LS 400 with 98k miles on it that has a whine coming from the power steering pump area. The sound does NOT change much when the wheel is turned. I checked the fluid and all is fine. My independent mechanic said it looked fine when he did the 90k service recently. But it is still there. It is worse at idle and I can actually feel a little vibration through the wheel. So I just had all the work done and the problem is still there. I took it to another mechanic who said the belts where fine and agreed the pump was going out and change it. What should I do? I have one guy saying it is fine and another saying it is not. Could it be anything else? Thanks in advance.

Gotta love the power steering systems on the LS400s. ;) Seriously, if its whining and the fluid is full, it may be going out. Is the steering hard to turn?

Power steering woes are no stranger to ANY LS400, but the 1990-1994 models seem to be plagued the most.

Good luck and welcome to these forums.

A $1200 "loss" over 2 years and 25k miles of driving is not a loss at all! It's simply the cost of transportation.

Thats what I was thinking too. Could not have rented a car that cheap. ;)

lol. Well I spoke too soon on the steering, because when I left for work this morning it was back to its old ways. :( I never went to the way it was before again today. I guess something is really screwed up with the steering pump or rack. I am not sure. Its like a switch is being thrown on the steering.

Anyway, the car is running very nicely since the throttle body was cleaned. ALL of that hesitation and stumbling is GONE! :) There was even a point where I thought my torque converter was bad because of the lurching... it was all the throttle body causing it.

I priced it to a couple of guys for $3000, but said I would take less since it needs valve cover gaskets and motor mounts for someone picky in the future, but most people probably would not even notice it needs motor mounts. If I sold it for even $3000, its a big loss on my part, but I paid too much for it when I bought it. I have put about 25K miles on it in two years, so maybe that will justify the $1200 loss, but its a little more that since I did replace tranny mount and fan bearing.

I am going to keep it priced at $2800 and may take a slightly less offer, but not much. I feel its worth at least $2600. Accords and Camrys of this generation in nice of condition are selling for that around here.

Yes, I highly recommend to anyone to get your throttle body done, or do it yourself if you know its not been done in awhile. You will not regret it!

I've seen a few salvage LS400s in yards with burned engines. What caused it, don't know. Any oil leak though is warrant enough to repair, and the valve covers are easy enough to pull. I did mine with the timing belt change two years ago, nothing difficult at all if you know your way under the hood.

Do the spark plug tube gaskets and valve cover bolt gaskets too, they're usually sold as a set.

Sounds scary. Good thing I have full coverage. :) Well, I have seen one with a slightly burned engine... turned out very near the alternator. I would bet it was from the power steering leaking down in the alternator and it shorted out. One other I heard of that had a fire near the upper part/center of engine near the EGR valve on a 1993 LS.

IF you do do it please take lots of pics. A DIY write up would be great. I have been thinking about doing mine for a while, but I've never had the courage or time. It seems pretty simple but that doesn't mean it will be easy. ALLDATA says its about 3 hours per side. That for a competnat tech, so I would venture to guess a day or even a weekend dipending on your pace. I think it is simple enough not to screw up so long as you take your time though. BTW time on valve clearance adjustment is 6.6 Hours and I checked head gaskets just for a laugh, 12 hours for one 14 hours for both banks. Don't pop one of them!

I will, but I doubt I will do it. I know I will screw it up.

Check this link though if you didnt already... its a good step by step write up on this that another guy wrote up.... take a deep breath! :)

Changing valve cover gaskets on a gen 1 LS400.....

http://www.lexls.com/tutorials/engine/valvecover.html

I read this DIY link: http://www.lexls.com/tutorials/engine/valvecover.html on how to change the gaskets yourself, but WOW it looks like a task.

Now that I have got a couple of other things done on my car, whether or not I sell it, I would like to maybe get these valve cover gaskets replaced, as they have been leaking for awhile now. I had thought about getting a mechanic I know of replace these or even do them myself, but rethought that after part about me doing it myself after I read that info on that link again. ;)

I know mine are leaking, because I do get a faint oil burning smell from under the hood, most of the time when the engine is full warmed, but what concerns me is that it will occasionally put out this big puff of smoke from the left rear side of the engine near the valve cover. One day I had it idling in the driveway and when it did it, I recognized it as the smell I had been occasionally smelling and it appeared from the back driverside of the engine. Its only noticable when it does that if I am setting in a drive-thru, traffic light, or stopping somewhere. Driving, I guess it blows away and not smelled.

I am assuming that oil is dripping down on the manifold when it does this, but its strange because it smells like diesel fuel smoke when it does it, rather than that typical burning oil smell. Its been doing this for awhile now. It must be so minor though because last couple of times I have let the oil go between 4000-5000 miles before changing and the oil ALWAYS stays full on the dipstick. I just dont want to cause a fire, but its been doing this for about 16 months now and nothing has happened. I have had a couple of OLD cars with leaky valve cover gaskets over the years and never any issues other than some smoke, but not sure how bad this leak is on the LS, where exactly its dripping, or how hot an LS engine gets or if it could cause a fire on this particular car. I know all cars are different and have different heat sources, etc. I know oil is not as combustible as gas, but still I guess if it gets hot enough it would. Anyone ever had a fire on an LS400 because of a leaking VCG?

It puzzles me though that puff of smoke and the smell of the smoke. Most cars when VCG leaks have a steady amount of smoke and it has a distinct oil smnoke smell. It would be nice if some sort of additive could be added in the oil to ease leaking of the valve cover gaskets or if slightly tightening those rear bolts would help, but look like a pain. There is probably no easy way around this other than replacing them hmm?

I have been wanting to get my throttle body cleaned for awhile now, but put it off. The dealer wanted like $120! I took it today to a shop that has about 6 mechanics (been around for years) and always stays busy. The guy that did it (older man) had a 1991 ES250, so we talked alittle about Lexus's, because I stayed in the shop as he did it. :) Hes not really up not up to par though, because he dont think an LS400 was made in 1990 and it started in 1991 and that in 1990 that it was a ES300. I just let him believe it, but we all know 1989 was the first year the LS400 was sold as a 1990 model.

My throttle body was terrible. It was all gummed up. It took him about 30 minutes to get it cleaned out, but he did and man, does it run so much better. That hesitation when I would first accelerate from a stop is gone, as is the "chugging" that I was getting on light acceleration between 35-50 mph as the grades changed.

After that, I ran more errands... pleased with the performance. Also another miracle (though it may be short-lived) is that when I slowed down off of the highway before I got home is that I noticed the steering seemed to be easy to turn... I pulled into my driveway and my power steering is back again! Even when in gear and stopped, I could steer with my pinky for the first time in about 6 weeks. Most of you know the nightmares I have had with my power steering lately. I am wondering if after I cleaned the pump screen that there was air in the lines? Apparently the screen was dirtier than I thought. I just hope it continues to work and not go back out. Its been a strange ordeal thats for sure.

Wow, I dont guess it matters now... after 30 minutes of driving it (took it to the shop and had the throttle body cleaned) the steering is now turning with ease..... even when stopped! Not sure how long it will last, but I am hoping it only had air in the line.

Well, after losing some blood and some skin off of my finger, I finally got the reservoir back on. We never could get the cap off of it, but I was able to clean the screen inside. It was really not even dirty... just a couple of small flakes in the bottom. Last night I did spray heavy jets of adhesive remover, the same solvent recommended to clean the screen on the solenoid. It set over night and this evening when I got home from work, it was so clean looking. I could even see the actual light bulb through the screens.

Billy, I read that link again and I can relate to that fellow. The front bolt that can be accessed through the holes in the pulley was easy... the lower side bolt was a pain and I have found out for me that the one nearest the engine on top is impossible. I actually left it out, but the two bolts holding it IMO secure it well. All they basically do anyway is give it extra bracing. Its too dark to see if the thing is now leaking since I disturbed the original o-ring. I hope not.

ANYWAY and unfortunately, it has not helped... steering is still as heavy as it was before. So here I am now. Fixed the leak, plugged the idle-up valve, replaced the rack solenoid with a working one and cleaned those screens, cleaned the screen in the PS pump, refilled with fluid. Still poor steering.

It does have SOME power assist, because when the car is off, the wheel is almost impossible to turn. With it running, it is much easier, but requires much more effort than before and the steering is "springy".

I am wondering if its simply where we plugged the ICV valve, but I dont think so, because it DID NOT do this the first two weeks the ICV was blocked.... even at a stop and at idle, it was easy to turn. I need to get some input from people that have actually plugged their ICV valve and comment on how much their steering has changed.

I dont want to replace the rack and it end up being the pump or visa-versa. I cant afford that. I owe $2K and if I can get that as-is, I will let it go.

Thanks again for everything.

**BTW, one of those pole looking things with a magnet on it is a must when doing this... it helped me alot. Without it, I would have lost most of the bolts. Also, this car is a tool eater too... drop stuff down in the front bumper its done unless you have one of these. Boy I love this car.

How long can you live without power steering?

I have a feeling that eventually you will get this sorted out. What's worse--being out $300-500 or so and without automobile transportation, or having a car that runs and drives but has some issues and still owe $2000?

Well, I have been without it (power steering) for about 6 weeks now and its really frustrating. I am trying to get it fixed so I can sell it.

Also, if I sell this car, I will actually have another car to drive, because at that point, I will sell my mom my very nice Mercedes for about $1300 (which is a bargain, because its a $3500 car at least) and I will then drive her car (1998 Oldsmobile) and then I will buy me another "days off" car... probably a nice early 90s Town Car, Caprice, Camry, Accord, Toyota truck, etc. Not another LS400.

I have owned alot of cars - some older and with many more miles and have never had the power steering issues on anything like I have had with this car. Its like chasing ghosts.... it cant be fixed. I keep thinking maybe its where I blocked the idle-up, but I dont think so, because for two weeks after that it did not do this and now that its started, it does it at all RPMS, so I dont think thats it.

Heck, I have two nearly 40 year old American cars and the power steering is like new... turns with ease with your pinky... no leaks and as far as I know, the fluid in one of them is probably the original fluid. Even my old 1990 LS400 (pictured to the left in my avatar) had nearly 280K and the PS was in perfect condition.

Good pics anyway, except for the last one ... looks kinda depressing.

;) It is depressing. This is the only place I had to keep the rain off of the top of my head. ;) Thats setting outside the door of my dads workshop where the lighting for this type of job was only slightly ample. I have a couple of good flashlights, but natually cant find them when you need them. <_<

Unfortunately I dont have a nice big heated garage like alot of Lexus owners have... but then again, most of them have 2001-2009 models and dont need to work on their cars in their garage. ;)

Thanks. Well, the one reason I was so puzzled thinking it wasnt the pump is because it happened so suddenly. To recap, it started about 2 weeks after I replaced the return like and blocked the idle-up valve. It was fine for two weeks... it steered so easily. Then.... it go to where I was getting a "shudder" / vibration at low speed turns.... it got worse and worst until it was getting to where the steering was becoming stiff and heavy to turn. There is no growling from the pump or anything... its just like its only putting out 20-30% power steering no matter the RPMs/speed.

I will go back and re-read that thread and hopefully I can get that cap off tomorrow.

Thanks again.

Come on Buddy, With the proper tools and approach/Mindset anything is possible, Hang in there and re-Approach with confidence. You can always (as before ) get all the support that you need right here.

Yeah, thats what I kept telling myself when I was trying to get the reservoir off. I come very close to poking a hole in the screen. That reservoir was a PITB to get off.... if I had of had hands as small as cats paws, it would have been OK. I honestly dont know if I will be able to get it back on.

Sad thing is I dont think the screen was clogged. I think the pump is shot, but puzzles me that it dont growl or make a noise.

Well, here is my old solenoid.... as you can see the end had to be cut off and placed on the solenoid off of the 94 LS400.

Here are some photos of this mess...

.... it was a heavy drizzle and fog, so I had to pull it under the cover out on the workshop.... not an ideal place to work on a car and the car was wet from being out in the rain....

UPDATE: I should have upated this thread as well... my steering is fine now... has been steering with ease for about 9 days now. Apparently had air in the lines. ;) Oh - also we had already dealt with the solenoid. Mine was bad. It was not clicking when we tested it, but Billy on here got me one off of a crashed 94 LS400... it worked (clicked) when tested (had to change the plugs, as the electrical connectors were slightly different), but I still didnt have PS for a few days... it was either air in the lines and/or the pump screen was dirtier than I though... either way its fine now... oh, I have the car sold... its going bye-bye soon. Kinda miss it already. ;)

Took me about an hour, (with crappy tools and poor lighting), but I finally got the power steering reservoir off of this crap car and I think it was a waste of time. The remaining fluid went everywhere... on the pulley, etc. I imagine I will have a majorly slipping belt, etc.

I can see light easily shining through the screen. Also that link says to "bend up the tabs" to remove the cover, but thats easier said than done. I cant figure out how to get them to bend up. I tried using a screw driver, but no luck.

I guess I will use that 3m adhesive remover spray and go ahead and spray it the best I can. To be honest, I may never be able to get the reservior on again.

I guess all that is left is the pump is bad or the rack. I owe $2000 on it and I am sure I cant get that out of it in its current state. I am going to have to lose alot of money on this car. I may can get $1700-1800 for it as is and let the new owner deal with it. :(

EDIT-

EDIT - I just realized that there are holes in the pulley center that allows access to the bolt, but I took a bright light and shined down in the reservoir and the screen LOOKS clean unless the little holes are clogged. ?? I dont see any big chunks of anything.

I just cant figure out why my steering is so stiff at all speeds. If it were the pump, I would think I would hear a noise from it.

dont know. could mean heater fans.

Not sure if its right or not, but this is how I was told to run the vac lines after blocking the idle-up valve. I was also told you can simply "cap" both of these off with those little caps. My smoke on start up went away immedietly once we did this. The idle-up valve was never causing my car to drip the fluid on the ground... it was only causing the embarrasing smoking on start-up. The external leak ended up being the return line on the back of the reservoir. Leaked for two years and I never knew thats what was leaking. It was a $2 hose and about 10 minutes to replace.

For those of you that are battling or may battle in the future (and you eventually will) the power steering rack solenoid on your 1990-94 LS400, keep in mind that somewhere between 1991 and 1994, they changed the electrical "plugs" on these solenoids. I have a 1991 LS400 and our good member Billy Powell on here was able to salvage me one off of a crashed 1994 LS400 and while the solenoid itself is indentical, my dad called me at work today to tell me the 94 LS solenoid would not plug into the rack on my 1991, as the connector is slightly different. My guess is that they may have changed the connectors on the solenoid in 1993 when Lexus did those what, "99 updates"? <_<

He had to actually cut the connectors off of both of these and splice the end of my solenoid connector to the 94 solenoid. Sadly, I still have heavy and stiff steering, so apparently it was not the issue, unless the changing of this end caused it to malfunction. I dont know, but I know this is really frustrating.

Tomorrow, my plan is to try one LAST thing... I am going to clean the screen in the bottom of the power steering pump and see if that is the problem... other than that, all I know is that the pump and/or the rack itself is shot. Not good news for a poor guy and why a poor person should never own a old LS400 with over 200K. ;)

Thanks to everyone for the info and replies over this 6 month battle I have had with my power steering issues... its been one thing after another. I finally got the leak and the idle-up valve smoking issue resolved, then everything else started happening with the steering. Oh well. :(

Just wanted to pass this info along on the changes.

Well, I for one love this thread. :)