ChrisG1000

I have a '94 LS400. This morning it would not start. It clicked and tried to turn over for a second then just stopped.

I checked the battery voltage and it read 12.4 (which I thought was good).

When I jumped the car it started just fine.

I'm now thinking the battery is bad, but it seems like the voltage is fine. Any ideas would be greatly appreciated!

BrittonJ85

I would start with replacing the battery 1st and then if you do replace it and the new one dies then more then likely your alternator could be die or on it's way out the door. But yeah from my learning experience start with the battery, then test the other electric parts such as alternator, spark plugs, spark plug wires, distributor rotor and caps etc.

Let us know what happens next after you purchase a new battery.

ChrisG1000

Installed a new Duralast Gold (only battery I could find locally). Fired up like a champ. Seems to have much more power than it did before.
Therefore, it was likely the battery. We'll see what happens in a few days, though.

BrittonJ85

Yup sounds like the battery.

ChrisG1000

Phew. I just bought this thing (for my wife).
I read a TON of good things about the cars, but the more I read in this forum the more worried I become.
This is a very complicated car- mostly from an electronic standpoint.
I hope I made the right decision buying it.

I will say that it drives like a new car, and is the quietest car I have ever owned. Beyond the quietness, there is not one rattle or strange noise on this car. Wish I could say the same about my 2007 Toyota.

LS4Lalonde

LS is a beautiful car and beats the pant off any newer car. I had a similar problem on my '94. Hope it isn't the TPS (throttle position sensor) and new ECU. Cost me around $1800 but was sooo worth it.

PureDrifter

iTrader: (10)

generally you need 13-14v to start the car, if it's sitting AT 12v exactly it's probably too low.

making sure the terminals are tight is also a leading cause.

deanshark

If you still have the old battery, you should give it a full charge and keep it in the trunk just in case the new battery goes dead for some other reason. Then, at least you wont get stuck out somewhere without being able to get a jumpstart. You can just change the battery and run it off the battery enough to get to a safe spot.

BrittonJ85

For some strange reason I still do not know where the ECU is for my LS400 but I can find the one for my SC400. I wanted to get one from the junkyard to keep in my parts stock collection just in case I may come across a issue with my ECU just as I experienced with the SC400 but I just can't figure out where to find it. Is it under the dash?

Also I would agree LS are awesome cars and very reliable depending on if the previous owner took care of their car and if not you can always restore it so that it will be reliable. I bought my LS400 as a project because it would not start so I had to replace a lot, from timing, cams, cams seals etc but it was all worth it because I love restoring a old classic Lexus automobile. Plus it makes you feel damn good when you say "yeahhh I restored it" if someone asked about your car lol.

deanshark

BrittonJ85; if ya searched for the ECU placement alot of threads would have come up, some with pics. But , The ECU is on the passenger side bolted to the lower dash panel.

BrittonJ85

Cool. Thanks!