Leadfoot

cant beat lexus quality!!!

Good move VMF!

I just bought a 98 LS400 and I can definitely feel a big difference in the driving experience from my 92 LS400. I really like the smart 5 speed box and the power that the VVTi gives. The digital readouts and non-blacked out displays are a welcome change too. However I think you guys have hit the nail on the head, how much can you improve the driving experience? Its 99% there now.

Thanks for the info, any threads you can point to?

http://us.lexusownersclub.com/forums/index...+wiring+harness

Thanks for posting the pics MW, it is always good to see real world test data. I have looked up LS400 crash testing on www.youtube.com and was impressed with the footage.

My commiserations on the loss of your car. Hope you are feeling better soon, good luck searching for a replacement!

Some great points SRK!

Do you have your owners manual? Mine states quite clearly the correct procedure for testing is when hot, and that cold levels are only a rough guide. But its important that its not too hot! i.e. 10 miles of easy driving I think was recommended. I would give you the details from mine but I am on holiday in New Zealand at the moment, so its a bit tricky!

Good luck.

Has anyone experienced the problem i'm having with my 91ls?

Fortunately quite a few people have had this problem, do a forum search on the classic "trunk wiring loom was made too short" fault, where the wiring has worn through due to use and causes a backfeed of voltage that gives your symptoms. You should be in for an easy fix.

Cheers!

So the one under the hood needs to be replaced as well?

hehehe the one thats blown needs replacing!

Right side of engine bay in front of the shock tower is the main fuse box, take the lid off and have a look under it, the fuse sizes and their function are shown inside the cover. Other ones in the driver footwell, get down to your toe view and you should see it.

Get a circuit tester and test the fuses for the dud circuits, hopefully the new fuse will sort the problem. DO NOT stick a bigger fuse into the holder to try and make it work, as there may be a fault (which caused the fuse to blow) and a short circuit is a great way to start a car fire.

Hope your problems a simple one.

Does anyone put new screws after installing rotors. My front rotors does not have screws, mechanic said "it is not needed". mechanic installed new rotors, and Front End Shakes When Braking. I wonder whether it is caused by missing screws.

Thanks!

I put new screws in mine when I did the rotors. The manual says to use at least three lugnuts to center the disc on the hub, then hold it in place with the screws. You could easily take off the wheel and look at the position of the disc holes in relation to the wheel nut studs. My new rotors could be moved around alot, although I don't know how much of an unbalancing effect this deviation would cause. Heck I might go and unbalance them just to find out!

I can gaurantee that toyota do not put in parts that are not needed, the japanese engineers do not think like that!

Congratulations and well done, we knew you could do it!

Is it all stopping smooth? How were the rubber boots in the calipers?

Take it easy on them till you have done 100 miles or so and then you should be a very happy person for a long time to come.

hey leadfoot

you might have noticed i have the same symptoms as craig down here, on your point about vaccum leak

i notice a hose its a 18 or 19mm diam.,going from inlet pipe of the throttle body to the cam cover, presumably

for crankcase venting, mine didnt seem to have a valve in it, thought this might have some bearing on things??

It may do if the valve thats missing is the positive crankcase venting valve.

Thanks to Carl we have some pictures...

http://www.lexls.com/tutorials/emission/pcv_valve.html

The workshop manual says

INSPECTION OF PCV VALVE

1. REMOVE PCV VALVE

2. ATTACH CLEAN HOSE TO PCV VALVE

3. BLOW AIR FROM CYLINDER HEAD SIDE

Check that air passes through easily.

NOTICE: Do not suck air through the valve.

Petroleum substances inside the valve are harmful.

4. BLOW AIR FROM INTAKE MANIFOLD SIDE

Check that air passes through with difficulty.

If the PCV valve fails either check, replace it.

5. REINSTALL PCV VALVE

Basically the PCV valve is a variable throat device held down against its seat by a spring. Under idle or deceleration the high vacuum in the intake lifts the valve off its seat, but the flow area is actually small. A heavier engine load means less vacuum, and the valve is not lifted so high and actually has more flow area.

If you did not have a PCV valve at all but the hose was connected then the flow would be high at idle, which could suck in a lot of oil mist into the intake chamber which would probably cake things up beautifully over time.

If your valve was stuck shut with gunk then the crankcase pressure could increase, but no where near the levels required to steal noticeable power. It's merely an emissions device.

Thanks to your question I have discovered that fresh air is actually sucked into the cam cover under the throttle body (check the pictures in the http://www.lexls.com/tutorials/EFI/throttlebody.html tutorial) by the crankcase vacuum created by the PCV, which recovers this air mixed with blow by from the pistons and burns it up in the cylinders. My last car was a 1978 MGBGT so this hi-tech stuff is all new to me. Its cool but complicated.

Can you post a picture of the cam cover end of this hose for us?

It would be nice if it was a simple $10 part causing the problem, lets see.

you're kidding me... they just clip in!?!?!?!?! so how does that prevent it from falling out lol

Once everything is bolted up there is no way for them to fall out. Putting it all together takes a bit of practice, but we didn't tell you that till NOW! It is fairly obvious once you have all the parts on hand.

Well... I just called up to Superior Lexus for the clips on the calliper and it costs $40 for the clips + freight/shipping... is there an alternative? I don't really want to pay $40 for a bunch of these clips... and how do I put these clips on anyways? super glue? lol

Also, how do these rotors and brake pads look? I want to save money, but also get some quality.

Fair enough, I was lucky and didn't have any missing. But there are three things you should NEVER skimp on when working with cars. Brakes, steering and tyres. Pretty much everthing else can fail and you stand a good chance of surviving. It is your choice, we can only offer our opinions.

I didn't put original equipment on mine and they are fine, but again its a personal choice. The ones you linked look OK from the photos.

Funnily enough the clips just clip in!

Let us know how you are getting on.

The ES300 that I had before the LS had EGR problems, and it was a snail (well more of a snail than usual. LOL) when the EGR was out of whack.

Thanks for the input Blake, the evidence is stacking up for some sort of vacuum leak/egr problem. The reason I want to go through all the error code diagnosis is that the manual says to do that first. If the ECU finds nothing then the troubleshooting matrix is used.

This matrix lists causes for the malfunction in rank of probability (one benefit from having the Lexus LS400 development program's 450 prototypes tested to death, thats a nice statistical sample!), and looking ahead a vacuum leak is listed higher than egr. The surging and poor power are typical symtoms of a open hole to atmosphere somewhere. Trouble is there are so many parts to weed through. That's where patience and a methodical approach will work.

Craig, the #SST 09843 18020 can be as simple as a paper clip, but I will take a photo of the device I made and show you where to position it. It is wise to have it insulated just incase you touch another terminal by mistake. SAFETY FIRST!! You are right hand drive too so it should be pretty close to my UK spec. My wife gets back from holiday in an hour so I will get the camera back, but will have to spend some family time this weekend so you may not hear from me for a few days. Have a nice weekend, as over the next few weeks I am going to work you like a dog.

You are going to need

1) a voltmeter,

2) ideally a spare 12V battery and some leads

3) some hand tools to remove some of the egr bits so we can test them.

Are you happy to pull bits off and get your hands dirty? If you can type an email then I believe you posses enough dexterity to get the job done, also is this car your daily driver?

Also can you please confirm that your gas tank hisses (i.e. sucks air) when you open the cap. The emissions control system is designed to have the fuel tank run under vacuum.

In your opinion - could an EGR related 'thing' cause my car to accelerate poorly when 'floored' from a dead stop?! AND cause a surging sensation?! Everything else seems to have been inspected, adjusted, cleaned and/or replaced.

Thanks!!

Craig!! :)

OH....MY......GOD. I just read the entire "please do me a favour" thread of yours and I had no idea how much torment you have gone through for such a long time. Dude, you have the patience of a saint.

Lets try and step back and look at your problem from the fundamentals.

Your customer complaint is

"my car is really VERY nice if driven only semi-aggressively. But after an hour or so, especially if I floor it from a dead stop, it begins to hesitate and surge and the gear changes become more abrupt. This is especially true when 'red-lined'. In fact - the entire 'feeling' of the car changes. It goes from being quite pleasant to quite frustrating and annoying. The idle also becomes erratic, like the engine is trying to clear its throat. It's noticeably worse at 1400 RPM's and 1800 RPM's."

A perfect engine will;

1) suck in the right amount of air and fuel

2) compress it

3) ignite it

4) get rid of it and start again, making lots of torque

a) Your problems may lie in the amount of fuel being delivered. I saw that you have had the fuel pump and filter cleaned and the pipes "fully checked out" by a doorknob. The interesting fact is that the fuel injection cut rpm is 1800 and the fuel return rpm is 1400. Hmmmmmm, a strange coincidence? ( I don't know what this means yet, I have to do some background reading on the EFI system)

b ) Lets say you had an airleak that was sucking extra air into the manifold, thereby reducing the proper fuel to air ratio. Well I think this is out since the ECU calculates the burnt gas ratio using those lovely new O2 sensors you bought it, and if it was out of spec it would tell you with engine fault codes 25 or 26 (but we will check soon anyway).

c) The EGR system could have a malfunction and be allowing recirculated gas into the intake, diluting the mixture and robbing you of all those glorious horses that you know live in that block. The ECU will only produce fault code 71 if the EGR gas temperature sensor is reading <65C when EGR should be occuring (i.e engine warmed up, below 4000 rpm)

d) compression should not be an issue on a motor as young as yours, and as you know its history you know the engine hasn't gone without oil for a couple of weeks during a drive through the baja desert. So lets discount this one.

e) Lets face it, you have done virtually everything to your ignition system. The car sounds good on the videos too, no complaint of a misfire as such. I want to discount this one too.

f) the exhaust system, if choked will prevent the flow of gas through you motor. But you say it does occasionally "run free", which is not a typical characteristic of a clogged cat. Lets ignore this one for now.

g) nobody has mentioned the gearbox. Maybe the engine is making making lots of power, but its being robbed by something in the gearbox. Is redlining good for them? The torque converter is fine though as that passed the "smoke the rear bags" test. When was the toyota "T-IV ONLY" oil last changed? I am going to assume you have serviced it at the correct intervals, but had to mention it as its part of the "powertrain".

Therefore;

Even though you only have OBD1, it has a highly sensitive diagnostic setting that it can be placed in that is used for tracking problems. Lets use it to eliminate some of the above items, namely b & c (air/fuel ratio amd EGR function).

Do you know how to read the OBD codes from your instrument cluster? if not please check some of my previous threads, I have rattled on about it quite a bit in here (click on my name and look for my previous posts).

What I propose is that we work together to eliminate the possibilities above till the culprit is found, and not spend any money on replacement parts (you have done enough of that already). Your car is working smoothly when taking it easy, so nothing is seriously wrong. It is obvious to me that you have the patience and determination to get this sorted, you just need some technical guidance to help locate the problem. I have the ability to read instructions (i.e. the factory manual), so we should be able to find where your variance from normality resides. Hopefully.

My old 92 also gets ropey around 1800 rpm, and I have a leaking EGR pipe. Maybe we have the same problem, which is why I responded initially to the EGR question. Hopefully we can both cure our frustrations and learn a bit about the wonderful engineering that is the LS400.

So bone up on my posts on reading fault codes and I will see you back here when you are ready to start or have some questions.

By the way i know this an off-topic topic for this specific forum,but i trust no one else more than you guys for a question like this thanks again......

We will try and sneak this one under the radar.....I am not a guru, but the toyota info service at

http://techinfo.toyota.com/ is only $10 to join for 24hrs.

You can download everything related to the specific car type, including all the LS models (getting it back on topic hehehe) including all the troubleshooting. Chances are the horses mouth will have the answer.

Good luck. ;)

Yeah.. the shims are accounted for, but they look like crap... I should buy some new ones... they don't clip on the brakes too well

I held mine on to the pads with a tiny dab of high temperature silicone sealant hehehe, if it gets too hot it will just burn off, and once they are in there they won't fall out.

What about the light?

It is an orange T-Rex. I'll post a picture when I get a chance.

Cool, looking forward to it.

The carpet itself is dry but there is still some water in the foam padding on the back side. We are getting some warm dry weather this week so it should be good to go by Friday evening. I'll put it back together then. I really don't have a choice. I need the car for work next week and my mother will need her's back when she returns from vacation.

JimA

Put it back in damp and you will be surprised how much more it will stink than when it just had cigarette smoke on it! Get some towels out of the linen closet and mash them against the foam, then put them in the laundry for your mother when she gets back!!

Actually don't.

I found about $3 in change, some costume jewelry, one Cheerio and a plastic dinosaur. SCORE!

What sort of dinosaur was it?

Seriously now, have you gotten it back together and smelling sweet yet?

Well... i decided to put everything back together because I think I will wait for a new set of rotors to come in... However... when I put everything back together.... my parking brake light is on and it won't go away... something tells me it's because of my brake pads

If its the light with the exclamation mark in the middle then its only the float switch on your brake fluid reservoir, when the level gets low it turns on the warning light. Check the level and that the switch is still working OK by taking the cap off you reservoir moving the float up to the top of its shaft, light should be out, then move it down the shaft and the light should come back on.

If you are getting pads it might pay to get the fitting kit too. Are the anti squeal shims all present and accounted for on the old pads?

I'm not aware of any tutorials on the subject for Toyota / Lexus vehicles.

Technical training course L752 has all you will ever want to know about air con, it is 9 pdf files about 3.12MB in size and can be downloaded from

http://techinfo.lexus.com

I just hope I never need it!

I dont have two screws that hold my rotor on as displayed in step 7 nor do i have a rubber thingy either and I can see where the screws should be.... I think i'm in trouble

Apologies, once you have completed the job it will be come clear. Also I forgot you didn't have the rubber thingy. reference the picture above. The parking brake adjuster should be able to be seen through the hole when the hole is rotated to the very bottom, you'll need a torch. Use a flat blade screwdriver to move the serrated adjuster wheel thats in the hole. Move it up or down depending on what loosens the shoes (sorry I can't remember which way it goes). Once you get the disc off play with the mechanism and you will understand it easily.

You will need the clips, they come in a "fitting kit", which is separate from the "pad kit" and "shim kit". I reused my old clips and put a little dab of anti sieze copper grease on the points where the pads touch the clips (a tiny bit only). You may be in for a trip to the dealer to get the "fitting kit", sorry I don't know the numbers.

But I'm curious. Is there more to the EGR than just the VALVE? IS there an EGR PIPE? [or whatever] Quite a few messages [here a LOC] seemed to go on about how difficult it is to change the EGR [something or other] and takes up to 5 hours to do.

Oh yes, there is so much more. To reduce nitrous oxide (NOx) emissions, part of the exhaust gases are recirculated through the EGR valve to the intake manifold to lower the maximum combustion temperature in the cylinders. The gas is taken from the exhaust system near the cat, up the back of the engine bay through the EGR pipe, which is notorious for leaking, and is a complete beyotch to replace (which is why mine is still leaking!!) to the EGR valve, which is in turn controlled by the VSV (vacuum solenoid valve) and the Vacuum modulator.

Basically the system monitors coolant temperature, throttle valve angle and engine speed through a combination of ECU control and vacuum levels to adjust the EGR valve settings. The exhaust gas is allowed into the plenum chamber of the intake, which is why the backs of our throttle bodies get so caked up with crap over time. Over 4000 rpm or below 55C coolant temp the system doesn't operate, other times it operates as it pleases.

Bet you wished you had never asked!

Also I don't know about cost, but your local Lexus Stealer will.

any suggestions on how to remove the rotor since I am trying to get it resurfaced?

Superb use of the camera, really helps us see what you are up too!

You may have to back off the parking brake adjuster thats accessable through the big hole that had the plastic plug. This will allow the parking shoes to retract and the disc will come off easy. Just keep going one way, if it binds up and the disc won't rotate then go the other way, but write down which way is which!!

For safety's sake measure the thickness of the rotors, new they are 0.630", worn out they are 0.591" so take a measurement and decide if its not better to just put a new rotor on. If you do end up putting a new rotor on take care not to put greasy fingers on the friction surfaces. You can clean it off if you do, but a little care will save the hassle.

Also please confirm that there are two 14mm bolts holding the non piston caliper side to the piston half of the caliper, you state only one came off?!!

nearly there......

Hokkaido Island forest pixies

Shouldn't it be Honshu Island forest pixies considering its Lexus? Those southern types found near Nagoya are a smaller variety, so that probably explains the accessibility issues, which I will encounter when I try and fix my leaking EGR pipe.

;)

If it gets low, do I even need to remove the cap then? Also.. im quite confused on where to put my jackstand -_-. If I am working on my rear right tire... and I put the jack in the proper place... do i put the jackstand on the left side of the jack(closer to my tire, or on the right side of the jack(further from the tire)...

I jack under my diff (manual page IN33 recommends this) and put the jack stand where you are putting the jack. The front engine crossmember is used when lift the whole front.

Perseverance is the key.

:D

I am not certain how important those two screws are. I recall a long thread either on this forum or on CL where some folks seemed to feel that they were necessary in order to keep the rotor from shifting slightly when the brakes were applied. This is hard for me to accept. If the lug nuts are tightened properly, I cannot see how the rotor could shift in the absence of these two screws. I suppose if the size of the holes through which the lug bolts fit were too big, and the lug nuts were not tightened properly, you could have some slight shifting of the rotor. This combination does not seem likely.

I just replaced my front rotors with SP slotted rotors. These rotors did not have the two screw holes. I have not felt any sensation that the rotors were shifting any when the brakes are applied.

Before I purchased these rotors, I discussed the need for the two screw holes with the sales people at Raceshopper.com. These are the folks from whom I purchased the rotors. They indicated that none of the after-market (non-Lexus) rotors come with these screw holes and that the only purpose for these screws was to hold the rotor in place when the tire is removed. I do not know if this was all fact or just sales talk.

I doubt that the absence of these screws is causing your car to shake. More than likely, your rotors simply need to be resurfaced.

Grandpa, I am referring to the two small screws on the outside of the disc that hold it to the hub, they are about 6mm thread diameter, usually corroded and sometimes missing (as in your case). I got my replacements from my toyota dealer for free!

On my 92 when I took the screws out I could mount the disc well off center. The mass of the disc is large enough that this imbalance would be felt at speed. The screws certainly could not transmit any braking torque, thats why the manual states you should do the lugnuts up with the wheel off so that the disc is centred exactly BEFORE you do up those two piddly screws. They merely hold the disc in the correct position, because there is no way you can move the disc once the wheel is being mounted and you are fighting gravity (unless you have a tribe of Hokaido Island forest pixies to help, they have very small hands). However the tapered face on the lug nuts does not protrude through the wheel so those who have off center discs won't know anybetter.

Maybe the aftermarket discs without the little screw holes have a much tighter tolerance around the stud holes and are therefore unlikely to be offcentre.

Sounds like you will be the master brake specialist around here in no time Grandpa! :D