realVIP

Hi Ladies/ Gents.

I am the new owner of a 1990 LS400. The car will NOT crank.

A little history:
The previous owner parked the car in perfect working order, for the winter about two years ago. In the spring afterwards, he tried to start the vehicle with no luck. he opened the trunk, and a mouse jumped out lol.

The car has not started since. As a troubleshooting measure, the car has had:
The starter removed/ replaced with a new one (by the Lexus dealer)
New battery
3 different ECUs have been tried (not sure of the condition of each of them)

I have not yet towed the vehicle to my place yet to tear into it, but I'm looking for potential fixes for this issue. I've done some searching, and I see that the Neutral safety switch could be an issue, other than fixing/ repairing this switch are there any other potential fixes that should be tried?

Here's a video of the what starting the car looks like while attempting to start. The Park & Neutral indicator lights do also illuminate on the dash

http://vid1253.photobucket.com/album...psj0n618os.mp4

Any advice that can be given/ you have is greatly appreciated!

dicer

How does a mouse get into an LS400? Not good. They like chewing wires and making a mess.

The security system is likely stopping it from starting.

realVIP

We did think of that, we put the key in the door and unlocked it so the security light turned off, still no crank. The neutral switch is questionable. The Park and Neutral indicators illuminate on the gauges, and we moved the shifter back and forth and tried starting in neutral position and still no go.

sha4000

iTrader: (1)

Is the check engine light on/

dicer

Check starter relay.
Also key switch.

Are you saying the Lexus dealer could not get it going either, after the big bucks for the starter change? What ecu's were changed? Ecu in lexus nomenclature is any Electronic Control Unit. There is one for just about everything electrical in the car. One for the security system, seats etc etc.

realVIP

I wasn't able to tell, because when the car is switched to accessory doesn't the check engine light stay on anyway?

This is correct, it wasn't running after the Lexus dealer replaced the starter/ checked the relays. Specifically the ECM was changed, there is one currently plugged into the car, and two 'spares' laying in the passenger side footwell.

The starter relay has been checked, but not the key switch to my knowledge, I'll investigate the key switch further.

sha4000

iTrader: (1)

You still should be able to read codes if any are stored.

randal

So, let me see if I have this straight...the Lexus dealer replaces the starter because the engine will not crank over, then gives up when that high dollar, shotgun approach does not work? You need to run far away from that dealer.

As a very simple first step, find the starter relay in the fuse box and determine if it is energizing when the ignition key is turned to the 'start' position. You should feel or hear a faint clicking from it.

realVIP

good call. I'll have to borrow a code reader and get it checked out.

According to the previous owner.. Yes, lol. I wouldn't have taken it to a dealer anyway for a repair like that. $$$$

I did check the starter relay previously, and yes when attempting to start, it does click.

randal

That is good news about the starter relay 'clicking'. At least it is being energized. That clears the park/neutral switches. The security system does not come into play with cranking the starter. The contacts could still be bad. Unlikely but maybe. Sometimes you can swap the horn relay with the starter relay (if the same).

It really is a simple matter at this point. So, the relay supplies +12v to the starter solenoid which pulls in the starter solenoid contacts and supplies the high current to the starter to make it whirl. Since the starter is new, it can only be several things. 1) no 12v from relay to starter...even if the relay is good, it could be that there is no 12v to the relay (fuse out). 2) Wire off from relay to starter (maybe mouse chewed it?). 3) No main 12v to the starter motor (that would be the big main cable). 4) engine is locked up (let's hope not!).

dicer

Also relay click means ignition switch start position is working okay.
? Security system normally does have something to do with starter, not sure how it does it though with out a study session. Well on 90 to 92 anyway. You need a wire diagram for that start system, to jumper the relay terminals to solenoid, could be a bad wire or connector. Or like posted above bad contacts in the starter relay.

randal

I checked my Lexus manual and the starter relay contacts (2,4) are fed by the + of the battery thru a fusible link. The relay coil(1,3) is fed from the + of the battery thru the ignition switch and a 7.5 a fuse. The theft deterent ECU provides a ground for the other side of the relay coil. So, Dicer is correct that the theft unit does affect the start circuit. I looked at a schematic online and it must be for a different model. Now, you could short pins 2 and 4 together on the starter relay and you should get a rise out of the starter. That would tell you that the new starter at least cranks the engine.

realVIP

awesome, great info guys. I'm having the vehicle towed to my place on thursday night (its 45 miles away), and will check out everything mentioned above on Friday this week.

Thanks for all the help/ advice. I'll be sure to update you guys when I get a result

Thanks again!

RA40

iTrader: (6)

This post may be of some additional help:
https://www.clublexus.com/forums/ls4...ml#post8263261

A sitting car with rodent/s is not a good combination. He and his friends could have eaten through many areas of exposed harness.

realVIP

Alright guys, I have an update:

Got the car towed to my place. I bypassed the starter using the steps from this site http://www.lextreme.com/dx-starter.html (about half way down the page) We used the battery on another car as the power source.

I have a video here to show you how it was done, and what it sounds like:

http://vid1253.photobucket.com/album...pshtcvg4zt.mp4


We've also cranked the motor over manually to make sure its not locked up. It spins freely