An Ls 400 In Dire Need Of Help

[dlssup]

I have an H reg 91 ls400 just reached its first 100k, owned it for the past three years and in perfect condition and running order when bought.

However after numerous services at a local lexus dealer it is now running very poorly.

3 services ago i could hear a faint tapping noise, sounds just like tappets, i had the work done at a local garage, could have gone to lexus but comments like 3k to fix the speedo slightly put me off. After three attempts to get the shimming done the car is still as bad as before. The car will run for approx 10 mins as quiet as a mouse after the shims are done then the tapping noise returns. Somehow is came back with a surging problem and stalling problem. i eventually bit the bullet and took it to lexus..i can hear the groans now. Was then told the engine had to come out and stripped as it sounded like piston slap and they couldnt tell me how much it would cost, after picking myself off the floor from laughter, i said no and eventually got them to look at the car properly and look at the cam tensioners etc, I eventually got a reply stating there was play in the tensioners and top pulley bely...650 to replace them and the cam belt, y not it was off...but wouldnt say if they were within spec or not and 50/50 chance of fixing it..anyway that was 650 down the drain..and still the car surged..much complaining later a new oxygen sensor and thermal sensor fitted...200 bill suppose to be in the 650 so a lot of complaining to lexus uk later bill dropped..lexus suggested having car for a week to see if it was build up around injectors...eventually they admitted there technicians dont have any experience on the old ls400 mostly on ls430, great help that is to the ones with the older cars

car runs low revs about 600 surges only after a cold night, still has its noise, on start up runs at about 1200 and drops down, quite to start with but gets noisier as it warms up, no throttle response between 800 and 1200 off load, This was a present off my wife who sadly passed away recently, i dont want to loose this car, any help would be gratefully recieved, thanks

dave

sorry for the long post

[ROYT]

Is there no throttle response 800 rpm and above with the engine hot and cold?

Does it sound like all the tappets are noisy or just one or two?

There are 21 options in the shop manual for 'surging', exactly what has been replaced?

If you try to drive the car does it stall?

[chips229]

Hi dlssup,

Sounds like you have been given the runaround and as to the Lexus Dealer they should know how to fix them the price they charge .

Phone Lexus Bristol...I went down there last year when i first bought my H reg 1991 LS400.

The technician really DOES KNOW his stuff and has worked on them right from the mk1 model like ours.

I will give you the Number to the parts Dept as its right by the workshop.

The technician You need to speak to is call Steve,have all details in front of you before you phone as he will be busy,But He will have time for you and like i say knows his stuff ;)

Parts number 01179165519

Hope that is of help Fella,please let us all know how you get on for future reference.

Cheers chips.

[dlssup]

It sounds as if it is coming from the drivers side bank only.

So far i have had a local garage do the shimming 3 times. Had the cam belt tensioners and the top pulley wheel bearing replaced. The stalling and surging problems did not start until local gargae did shims for the second time, i suspect an air leak but lexus says everything ii ok that way and ok from all the computer read outs.

The car does stalls mostly in reverse but certainly not as bad as it has been doing, the surging is better once i had recieved the car back from lexus but did still surge first thing after a cold night.

The throttle response is worse as it warms up but its not really noticable once on the move. The car runs perfectly once going, since the shimming has been done the cars acceleration is rather impressive sand feels smooth under acceleration.

lexus has changed an oxygen sensor and thermal sensor, they reackon they got a -25 deg C reading off it once. they assure me they have rechecked the throttle housing and its been reset on the computer, however i dont really believe this.

The car tapping noise is worse once the car warms up..water pump????? dunno.

Tick over seems fine when cold about 1200 to 1000 revs and slowly drops to 800 once fully warmed drops to 600. it feels as if it has a misfire very similar to when 2 of the leads went just after i got the car, this was due to over zealous cleaning of the engine and water had found its way into where the spark plug leads are routed over the engine. i have noticed the temp gauge is showing hotter than normal running, by about 2 marks on the gauge, strangly it does fluctuate between normal running temp the car always hads run at and this slighty higher level, i cannot say if its on acceleration or coasting during normal running, probably an air bubble in the system.

yes i would appreciate the number for bristol lexus, any help from a mechanic that knows what he is doing cant go wrong.

thanks for the help

[dlssup]

just seen number for bristol...thanks will ring it monday

[dlssup]

Finally after going through this site and its links i have found the problem. it seems the old ls 400 has a common problem with this ticking noise coming from the 5th and 7th cylinder. looks like the valves stick, small cap under the shims gets stuck, the description of the fault matches mine exactly, looks like getting the shims done has popped this cap back out but it has depressed after 10 mins, the shims now being set to the smallest factory setting gap seems to have made the ticking noise louder. I cant describe my disgust at my local lexus dealer, they knew this and went on a money making exercise, just wait till monday morning.

See how much is charged to remove the cylinder head , probably repair the head and fit a couple of valves...not a lot if i get my own way.

Anyway as that should fix this problem does anyone know how to refocus the laser on the old cdx-m97512zt, went off last year, or were to send the unit to to be repaired, rather do it myself have most of the tools to do the job, just got to find the cap to adjust laser beam, bit embarrasing for me cos i am in the laser industry but a bit higher power than this

Also does anyone know how to cure a sticky speedometer, awful when cold, doesnt move some morning till warmed up, seems like a loose wire, i have heard they have problems with the back light pcb burning out...would this really cause this problem, feels as i say a loose wire or perhaps adry solder joint, any help again appreciated.

[tangray1]

Just out of intrest for you if you go on the US site for SC400 (soarer) it gives a complete guide on doing the valve gaps very ez to follow and certainly doesn`t involve taking heads off ! Just to put my tenpence worth in I would put your surging down to your TPS (throttle postion sensor) being worn. :winky:

[dlssup]

Thanks for the info i shall certainly look, does it explain how and y these buckets under the shims stick, how is it repaired and how common is it for the fault to return, by the way lexus refuse to admit it is a common fault etc etc, what a shock.

[chips229]

by the way lexus refuse to admit it is a common fault etc etc, what a shock.

←

Yea they would make good politicians!!!

[93_LS400]

Well .. I've got the same problem but haven't got round to fixing it yet.

the problem is a known one with the 1UZFE engine generic, this is where you found the 5/7 cylinder thing [ on the 1uzfe engine forum ] , but you'll find a lot of dealers who don't bother proper fault finding and go on money making exercises rather than fixing faults

or who don't do any research .. this stuff isn't in the standard manuals...

If you find a good dealer who knows the 400s stick with them like glue ...

[dlssup]

From the guys who tried to shim the engine it seems the problem is with the number two cylinder on the drivers side as looking from the front of the engine, which cylinder this is i dont know at this point. What actually needs to be replced or what really needs to be done to fix this problem, some say its a quick job others u have to remove the cylinder head, looks like i will need a fine weekend in either case, not that im holding my breath for that, bit like finding a proffesional lexus dealer, few and far between.