I've scoured the forums and no luck. So now I turn to starting a thread to see if I can find the answers.

To start off, I sold this car to a buddy of mine in perfect working condition [it was owned by a mechanic for 18 years prior to me owning it]. My buddy is not the nicest to vehicles and that's putting it lightly. On Christmas eve 2022, he ran from Georgia State Patrol and got pit maneuvered and ran the car into a telephone pole. He ended up selling the car back to me rather cheaply because he couldn't get it to stay running. I fixed it by replacing some broken vacuum lines and the radiator. The car drove fine for a few months and around April of 2023, the car started intermittently starting. I tossed it up to a dead battery and would start it up with a jump box. On Easter while riding down the freeway, it randomly stalled out and then started fine when I cranked it back up again. My thought was a bad alternator, so when I got home that day, I unplugged the battery and left the car running off of the alternator and it did so until I turned it off. After that day the car hadn't started back up.

Fast forward to today. I decided to start working on it again and figure out the issue with it. I tried jumping the battery with another vehicle for 30min but to no avail. I took the battery up to Autozone and had them charge it up, which took 3 hours and then had them test it. Their verdict was that it's fully charged, but the battery is bad. Even knowing the battery is bad, I wanted to test the alternator again, this time with a multimeter, to ensure it is supplying ample charge to the battery. Since the battery had 12.4V when I hooked it up to the car, I jumped it off with another vehicle again and it started. I checked voltage and I had 14.2V. I then threw a load on the car with heater all the way on, lights, and radio and the voltage dropped a little, but maintained at 14.19V [due to the bad battery dropping voltage]. So I no longer think the alternator is the issue.

Once I turned off the car and unplugged the jumpers, I tried to start the car again. Once the ignition turned to the RUN/START position, you hear a click and all the lights on the dash went out, like it completely lost power and does it every time since. So my question is, what could be causing that issue where it clicks once and then kills the power to the car? Trying to start it after that, it will make multiple clicks like the battery is dead [obviously, the battery is bad]. Besides the battery, should I be looking elsewhere? Faulty Ignition Switch? Faulty Starter [Though I doubt seeing as it cranked fine with a jump]? Any help is greatly appreciated!

SUMMARY:

--Battery has been charged but diagnosed as bad
Voltage of battery when put into car [12.4V]
--Multimeter Test for Alternator from battery posts:
NO LOAD - [14.2V]
W/ LOAD - [14.19V]
--Car cranks with jump from another vehicle
--Without being jumped, car makes one click noise and kills power to itself when trying to start
--After that, it'll make multiple clicks like it is dead when trying to start.
--All fuses in fuse boxes are fine

QUESTIONS:

--Could it be a faulty Ignition Switch?
--Could it be a faulty Starter?

Any help from any of you fine people here would be greatly appreciated. I really don't want to start throwing money at parts to fix the issue if it isn't needed.

 

You might have a bad battery. I have a camera I use, it will fully charge but the batteries are so weak the camera won't stay on by itself, it just shuts down. I am not sure why you are using a known bad battery yet are looking at other things.

 

I found out the battery was bad today. I put it back in just to ensure my alternator was functioning properly and the alternator wasn't the issue that caused the bad battery to begin with.

Would a faulty battery cause the issue I'm having when trying to start the car? With the complete power loss to dash lights and everything, even if the battery is just slightly lower than optimal charge? [Optimal being the 12.6-12.8V and the bad battery sitting at 12.4V]

 

Not sure, you stated the battery was determined to be diagnosed as bad, so I am using that information. It's not the charge that is the most concerning thing I am thinking about, it's determining if there is something fundamentally wrong with the battery as battery's have welds that can break inside a battery, or stratification, things like that.

 

I mean if the car physically slammed into a telephone pole, its not unreasonable to think it could have broken some internals of the battery that is I am assuming it is the same battery still in it, but even if it's not the battery still is diagnosing as bad.

 

It was the same battery from when he wrecked it. I plan on grabbing a replacement battery on Tuesday since the battery is still under warranty for another year. Once I get that battery, I'll perform another multimeter test and hope that the issue is solved. I'll definitely keep everyone posted on what's going on with my issue. Also, Happy New Year to all of you guys!

 

I got the battery replaced finally and has been in the car for 2-3 days and the car starts right up. I still have to check the car doesn't have a parasitic drain with the multimeter today when I get home to ensure there isn't any other underlying issues there. If all is well, then I'll be moving on to basic repairs, like new tires on the front end, front end alignment, replacing the passenger headlamp, etc. Thank you CLLEXUSS for responding to the post.

 

@CELSI0R @CLLEXUSS So just tried to start the Lexus and got the click sound in the dash and then all lights to the dash go off and the car acts as if the battery is dead even though the radio clock is still on. I multimetered the battery right away. I have 12.3V at the battery. Any direction I should be heading for this?

 

EDIT: What I wrote below about CCA is good to know, but I just realized you've replaced the battery.

If you manually put the car in neutral (I assume you're trying to start it in park), does it start up?

To move the shifter to neutral, make sure the parking brake is engaged (so you don't roll of course), then hold down the button next to the shifter labeled "SHIFT LOCK OVERRIDE", and move the shifter into neutral while the button is being held down.

Also check all of your fuses to make sure none are blown and they're all the correct amperage rating (shown in the owners manual).

If you need an online owners manual, please see these official documents from Lexus' website. Select LS 400, 1990:
https://www.lexus.com/My-Lexus/resou...d_guides_promo

Electrical section for fuse boxes:
https://assets.sia.toyota.com/public...df/6-4_212.pdf

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Good to note but not relevant at this time - about battery CCA
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I noticed one item wasn't mentioned in the battery test - apologies if I missed it

What is the CCA (Cold Cranking Amps) rating on your battery? It should say on the battery itself on a sticker. Also, what does is the remaining CCA on your battery after running the test. Any battery test at auto zone or advance auto, etc should be able to give you a receipt with the results.

If I remember correctly, batteries for this car should be rated at 750 CCA

When the battery cannot provide enough current to turn the starter (the starter has to pull a lot of amps to turn over the engine, especially in the cold and since it's a V8), then the car won't start.

This would make sense with why the car cranks when you jump the battery with another one, but not by itself and basically dies.

Also, how old is the battery? There may be a lot of internal resistance between the cells.

If the CCA is too low and that's the reason for the battery testing bad, then you likely need a new battery or need to desulfate yours. There are trickle chargers that will desulfate batteries, but this can take a few days and won't necessarily restore the battery back to new depending on how far gone it is.

 

CELSI0R. I was going over the car again to see if I missed anything, all fuses are good and correct amperage. I noticed my terminals were corroding more onto the new battery posts, so I went to the auto store and bought a wire brush to clean off the posts, some terminal protectant and 2 new terminals. She seems to start fine now. Probably just really corroded terminals, they seemed to be the originals on the car. My next project is finding a yellow clip off of a harness for the passenger side airbag sensor. Mine is busted and wires are cut. I found a used one on ebay, just waiting to see if the guy will sell it to me cheaper.