squirralie

Hi, I am just wondering if anyone has any ideas about the Lexus LS400 1993, We were driving along it was running as it should and just like a click of a switch it had no acceleration and a slight vibration coming from the motor under acceleration, when the car is sitting still at idle it sounds like its got a slight sore throat and the slightest of rough running so slight that the engine is still stable and not rocking on idle,,, I have a tune up kit with plugs leads dizzy caps, rotor buttons and coils so I will try that tomorrow thinking maybe one coil may have packed up,,,
How many petrol pumps are on these cars, it seems like half of the motor is running but its still relatively smooth running.
Any suggestions would be appreciated, maybe some things I can check out tomorrow, thank you

RA40

iTrader: (6)

With this running condition, is the check engine light on? If so, the easiest route is reading the error codes. That will tell you more precisely what needs attention. Could be a coil pack or wire.

YoshiMan

There is just one Fuel pump on these.

squirralie

Thank you both RA40 and YoshiMan for your replies,

No there is not an engine light on, Well fingers crossed its the coil pack because I have two new ones here and Ill replace them today along with the plugs leads and dizzy caps and rotor buttons.
there will be a big deep breath on starting this job hoping it gets sorted, I'll give feedback after the jobs done on if there is any improvement at all,, thanks again

squirralie

whats the best way to read error codes, I guess the hand held diagnostic machines? ,, or is it possible with a laptop and some software, I would love to be able to do it with a laptop

Hodson

I believe your car is OBD I, I don't believe that a code scanner can hook up to it. You have to jump a couple terminals with a metal wire and count the blinks of the CEL on the dash to give you a code number.

http://www.lexls.com/tutorials/intro/codereading.html

squirralie

Well I just replaced the plugs and leads and after all that didn't have any coils, bugger, I tell you what I am sticking to the holden straight 6 to work on and never want to work on the lexus motor again, mind you doesn't help when some rubber lines are snappable, but also broke a plastic T piece thing that comes out of the air intake
Any way no difference so its off to Lexus I guess for the bill of a few grand I am guessing,
bloody took me about 6 hours to pull it to bits and put it back together and no difference,, I have a lot of pain from a medical condition so no doubt that took its toll on the time but just makes it so much more disheartening when it made no difference, ill suffer tomorrow for todays efforts,,,,

squirralie

Hodson, it has a diagnostic socket under the bonnet on top of the motor,,, is that for the hand held device or pin shortening as you suggested

cobalt91

There should be two sockets. One on the driver side of the intake manifold and one near the steering wheel. Is your ls right hand drive?

squirralie

yes right hand drive, the socket under the bonnet is on top of the motor and only just on the passenger side of the centre of the motor, I think I have seen the one near the steering wheel before.

LScowboyLS

this kind of problem is almost always electrical, and is often caused by bad ECU capacitors

This ECU issue happens on all LS400's/Celsiors and is especially common on 93-97 models

squirralie

Thanks LScowboyLS, are they usually expensive fixes, The car is in at the local Lexus dealer so I'm not expecting it to be cheap but I am just not knowledgable enough to locate the problem myself and we don't have time for experimental fixes so all I can do now is keep my fingers crossed and Ill update this thread when I know what the issue is,,,,
I guess the ECU can make it run rough as well considering it probably controls most aspects of the motor running.
Maybe I should have located a good s/h ecu, I am sure a new one would cost the earth if they are available, couldn't imagine them repairing it

squirralie

I just read the symptoms from the post you linked me to and the only symptoms ours had was the running a bit rough and the poor acceleration, everything else seemed to be normal,,, maybe in its first stage of playing up,, but I will report back hopefully tomorrow because they said they should have a diagnosis by lunch time.

LScowboyLS

you don't have to have ALL of those symptoms, it starts out with just one of those symptoms, then the problem gets worse over time.

and no, the Lexus dealer would not be the place to have this fixed, that would cost $3000

squirralie

oh, now I'm excited haha,, $3000 is a big repair,,, fingers crossed for tomorrow but it does sound like it,