Mk1 Ls400 Engine Warning Light With Lack Of Power?

Manc · June 18, 2008

Recently i saw an article on the MAF sensor, some of the description of the engine fault sounded similar to mine so i printed off the walk-through but it was off another engine the 3uz-fe or whatever it was. It was basically the air-flow sensors and looked very similar - until i took it apart and typically it was a different part to the one shown. I compared and there was nothing to clean, no sensors i could see etc.

i didnt mind taking the air filter and stuff off because i was doing the popular p/s o-ring replacement too and it gave me better access but.........

Can anyone shed any light my engine. It was fine late last year, then it was off the road for a few months and it had a service while it was stood. When it moved again it had developed a slight pull or lack of power when i needed any acceleration - the less revs the worse it was, it still did it with lots of revs but not as much - prob just because of its own power anyway

i noticed when i came to drive it the wrong transmission oil was put in (brown stuff, should be pink? well at least i know my cars not gay

This isnt the fault i know but it makes me doubt the mechanic, having changed all the plugs and leads im thinking is it a timing fault?????? But he's a respected guy etc..... so thats what took me have a look at my air flow sensor.

But now im back again.

The car doesn't do it all the time, say around half and half really - its why ive not took it in yet because it'll probably be the day its ok and then im left with more "we need to plug the computer in" charges.

Any ideas you people??? Gotta say you're a top bunch

Cheers for any help...........................................

Bigste · June 18, 2008

These cars are noted for being very fussy over transmission oil. You must use Toyota type 4, nothing else will do. You need to completely get rid of that old oil before progessing further.

steve2006 · June 19, 2008

Hi,

As Bigste says get the ATF replaced with the correct Toyota Fluid ASAP but the EML light and the lack of power suggest the engine is in limp home mode due a defect somewhere.

You need to interrogate the diagnostics to obtain the fault codes and below is a link to assist you to do so.

Good luck

http://www.troublecodes.net/Lexus/

Manc · June 19, 2008

Hi,
As Bigste says get the ATF replaced with the correct Toyota Fluid ASAP but the EML light and the lack of power suggest the engine is in limp home mode due a defect somewhere.

You need to interrogate the diagnostics to obtain the fault codes and below is a link to assist you to do so.

Good luck

http://www.troublecodes.net/Lexus/

Thanks BigSte and Cheers Steve06 - Your help again and those codes are super. I'll let you know what code it was - prob gonna be weekend now.

Its not quite in limp home mode (I've experienced this on a merc van), its just a tiny pull / dip in power for a split second or 2, i might get 2 or 3 of these 'dips' when more revs needed. Its like im messing with the accelerator but my foot is still.

I suppose its choking or starving of something or similar. Some american (eng & trmsn forum) says the wire loom in the boot frays (he said trunk). Near the left hinge and it does funny things to the engine?? It sound dubious i know but he swears his was ok after he re-wired. He listed 3 faults where people have had to put a/c on to stop it stalling when speed is reduced. Mine doesnt do this but my fault was mentioned in there - in fact i'll try to do a link..... http://www.lexusownersclub.co.uk/forum/ind...showtopic=44782

had to cut & paste it so dunno??? Its uk forum Eng & Trans, huge title: 1991 LS400 hard to........look for the reply by Alex the OK - it made me laugh, but i might have a look too

Im not a mechanic but will do stuff - how hard is cleaning the throttle body? and is changing the gear oil ok to do (i know it wont be easy)

Big thumbs up to the two Ste's

Manc · June 19, 2008

Does the ATF change need any new parts too?? like sump plugs for normal oil, or any gaskets.

Thanks for the tip - i do notice a slight gear change now so i thought i might have to change it - wont be going to that mechanic again. I was gonna check spark plugs too cos he did a service on it a while back, but to be honest it fires up instantly and i thought any plugs or ht leads that were wrong would affect all the time - mines just occasionally at the mo......

Haylands · June 20, 2008

Hi

Do you definatly know that someone has put the wrong fluid in the gearbox or do you just presume they have because of its colour.... only brown auto transmission fluid is a sign of a worn transmission, the fluid starts off nice and pink and when the bands in the box wear they stain the oil brown. If you want to do an oil change you will need a sump gasket and a new filter, you remove the sump to drain the oil, there isn't a sump plug, and change the filter at the same time. If there is a large amount of metal particles in the bottom of the sump then start looking for a new box.

Sorry for delivering bad news....

Pete

kendr · June 25, 2008

Do you know for sure that your mechanic changed the plugs etc, The reason I ask is that it is quite a long job and I found out that mine had not been done for way over 150,000 miles. It too was missfiring slightly as you state. Also as it had been standing, is there a chance that moisture has got to the HT system?

cleverdick · June 25, 2008

Check out www.lexls.com for how to do such things as change the ATF and clean the throttle body, both of which should give a vast improvement. You definitely need to get that trans fluid changed immediately - by the sound of it I doubt if it was done at all. It's not that bad a job to do, providing you allow yourself time and space and be sure to have everything to hand before you start. I did mine a while back (started a thread on it here somewhere) and it has not put a foot wrong since. (Not that it was causing a problem beforehand, except that the fluid was brown and therefore tired). I cannot stress enough the importance of using only Toyota Type IV in the transmission, regardless of what anyone tells you - including the Lexus or Toyota dealer. Don't let them dupe you into buying an 'equivalent' because there isn't one. Just be prepared for an argument with them before they order it in for you. And it'll probably cost over £100 for 10l, but that's what you need and there's no way round it I'm afraid... :-( Plugs should be Denso iridium, and you may as well change the leads as well while you're at it. I'd always advocate the use of genuine Toyota parts, because although they are much more expensive, they are invariably cheaper in the long run because you avoid the hassle of having to do the job twice. (ADL parts are pretty good if you can't get OEM). At least if you do the work yourself you know that the job's been done right (well, at least done!) and you can take your time over it.

All the best...