kamtra

This is my first post. I bought a 90 LS400 with all options (120k miles, dark green/grey) two months ago. My first Lexus. I'm very impressed with the quality of assembly and I've decided to keep this car as my daily driver for a long time. I also have 87civic si hatch that I autocross and a silver 84 volvo turbo wagon (everyone should have one).

Last week I installed a new timing belt (yes, myself) and rotors. While I had everything in pieces I thought I'd change out the idle up valve that everyone (including me) has problems with on the power steering pump. The valve is in a crappy place to get to and I gave up pursuing it further It's about an inch from the strut tower wall. So, what I did was take the two vacuum hoses coming from the valve and connected them to each other. I wasn't sure what this would do to the idle or the steering but I have yet to notice any difference- besides the fact that the car doesn't smoke when started anymore. Things may change when it gets colder though. BTW, if I had a lift in my garage I probably would have change the valve- even though they cost $100 or so.

Also, after much investigation I discovered that low and behold, the non air strut from the LS400 replaces the air strut perfectly. PERFECTLY. I have no idea why people don't do this. My left side strut had a leak- Lexus told me that the stock shock would not work because the control arms are different. Well, yes, they're different but the difference has nothing do do with dimensions or where the strut mounts. The difference is that the air equiped arms have an extra hole in it for mounting the ride adjust lever that lets air out. I'd have to look again to be sure but anyway....I went to a salvage yard, bought a complete set of four shocks for $200 and slipped them into place in about two hours. Also, the MKIV Supra shocks mount the same at the top and bottom end- not sure on length though.

I installed a K&N filter charger to make the car sound meaner. It sounded awesome but the mass air-flow sensor hated it and made the engine hiccup and die sometimes. I put the factory stuff back in and everything is fine now- except it's too quiet.

The left side speakers front and rear didn't work when I got the car. Thought is was the Nak unit or amp. Turns out that both speakers were just bad. Replaced them with some old Infinity kappas that I had laying around. Had to cut up the wave box a bit but the left side still sounds as good if not better than the factory right side.

Fixed my drivers seat too- was reclining only on one side. That was not fun. Scratched the car taking the seat out too!

My AC unit LCD was showing no digits so I took the three bulbs out that lit it up and used them to replace some that had burned out in the buttons. Now I don't even notice that it doesn't work because it doesn't stand out. I highly suggest doing this!

I made a new grill out of expanded steal and painted it black. Fitted it inside the chrome frame and it looks really good. I'll post pics soon. The metal cost $5 and it took a hour or experimenting to do. I HATED the factory grill.

I have questions about brakes. The SC400 can use Supra TT calipers and disks but I don't know about the LS400. Has anyone seen the brake setup on an SC400/GS400? Are the caliper mounting holes the same dimension or will I have to fabricate something?

I'm still trying to figure out my half dim speedo needle. I've read all the posts but I like to do things a little non-traditional.

I'm also looking for 17 inch wheels.

Thanks for all the help- I feel like I know you all from all the reading I've done on this site the past two months.

James- kamtra

GA400

Hi James,

Thanks for sharing your findings. It will definitely save others some time and money, especially the findings on the fitment of standard shocks vs. air shocks. I am very interested in seeing your grill, that sounds interesting. I have a 91 LS and I agree that the stock grill is boring.

Thanks,

Rich

persian451

good post, let me know about the grill as well.. I need a new grill without unloading my wallet

kamtra

I love taking pictures but I'm still stuck in SLR land. No digital for me...I'll get my pics developed in about ten days (I take lots of pictures) and I'll post them here. At first I kept the expanded steel in it's original color of silver. It looked very street racer. I thought I'd paint it black just to see what it looked like. Now it looks kind of like an Acura. Both are a drastic improvement but I think I actuall like the silver one better.

RA40

iTrader: (6)

Great post.

In the Suspension section JBrady was mentioning the possibility of a big brake swap for first gen LS4's with the second gen LS4 brakes. As he also stated, the setup resembles those from the 4'th gen Supra. The Supra has some nice brake kit's to choose from.

Toyotas have a fair amount of cross compatibility as judging by past models...however until a hungry LS4 owner comes along, much is theory.

kamtra

Okay, I got sick of the black grill and got some really thick expanded steel from a metal shop. So thick that I had to use an angle grinder to cut it. After an hour of sweat it's on the car. I love the metal look. If only my car were silver!

HMCGARY

Do you have a picture or diagram of the idle up valve?

bokomba

I read something very interesting you wrote. I have power steering pump trouble. I just replaced my second alternator because of the PS leak. You mentioned something about smoking when you initially start up before you by passed some valve. I am experiencing the same problem, please elaborate on the cause and the relationship between the smoking and the PS system.

Thanks Ben.

retrodrive

I never knew about the strut conversion. I need to do a howto on this. People are spending way too much $$$ on replacing air suspension. Very cool that you can work on your car yourself. About the supra brakes, I am not certain but the SC430 brakes won't fit.

rybikowsky

Thanks for shareing. This type of info is why I use this site. You have just saved some people a lot of money.Carpe Diem. Michael

kamtra

Ben,

Somewhere on this site there's a diagram of the valve. If you're looking at the power steering pump from the top, it's on the bottem left side between the pump and the wheel well. There's only about an inch gap so it's hard to see. It's a little valve about the diameter of a quarter and an inch or so long. It has two vacuum hoses coming out if it. One comes up and attaches to the intake between the silver square thing with the mass airflow sensor (MAS) and the black plastic bend pipe that connects to the throttle body. It's the first vaccum hose, er, come to think of it, it's the ONLY vaccum hose connected to the intake piping. The other hose snakes up and connects to the intake manifold (the big pretty thing on top of the engine) right in the front- dead center. You'll know which one. These hoses signal the pressure in the power steering pump, telling the engine when to "idle up" and when not to during steering.

The valve and the hoses are just supposed to have air going through them but after awhile the seals that separate the power steering fluid and the air start to leak and power steering fluid makes its way up the hoses and into your intake- thereby making it's way into your engine. It collects in there so that when you start your engine a big puff of blue smoke emerges- freaking every Lexus owner out. Typically, blue smoke means that your piston rings are leaking engine oil into the compression chamber and igniting along with the gas. The solution is replacing rings which costs a fortune. Fortunately, I've never heard of a V8 Lex having this problem. At 125k miles, my cars engine oil still looks clean when it comes out. These engines are truely the best thing that you can get for under $100,000.

I'm getting off the point- I've had too much espresso already this morning. Anyway, the blue smoke for us LS owners simply means that our "idle up valves" are leaking PS fluid into the vacuum hoses and possibly even dripping out and into the alternator. The valve costs more than a hundred dollars and is in a bad place to try and get to. Any half way decent mechanic can do this job though if they have a lift. Just show them the new piece and tell them where it is. I'd take it to a gas station or something- not the local Lex dealer. They only know how to make money.

kamtra

I went to a salvage yard yesterday and looked at a first gen GS400. The rear suspenion was very different than the LS with shorter shocks and control arms, but the mounting holes for the caliper looked to be in the same place. I'm still trying to figure out how to make my brakes larger with little expense. I may have a Lexus but I'm still cheap

retrodrive

You can always borrow the brakes from junkyard and try them on. Ask them if they have some laying around and leave a deposit.

bokomba

Kamtra,

Thanks for the info. on the PS idle up valve. You're very right that cloud of blue smoke at start up, freaked me out for a long time because I know my engine is tight. I litterally have to drive 7,000 miles (I use syn. oil and drive alot) before I notice a slight change in oil level. I finally can solve this problem and not get embarassed in the mall parking lot by a smoking Lexus whose engine I know is a heavy weight.

By the way welcome aboard we can learn alot from you.

kamtra

Because of my super happiness with the grill I made, I'm currently making a chrome/steel plate to put where the shift console is. You know, the thing in front of the arm rest that has the letters for park, drive, reverse and such.....I've noticed that all the new luxury cars have chrome there. What I have now is black plastic and large squarish letters that look remarkably like a Camry. I think I can get one made within a week. If it looks good I'll post pics to see what you think. Something like this should cost less than $15 but make a big difference in the interior. I'm also thinking of replacing the wood around the power window switches on the doors. I'll also make a plate to completely replace the wood piece in front of the center armrest that always cracks with age. I'm not sure how good it will look all chrome but it'll be easy to make. Anything is worth a try.