Hey guys, i ran into a small (massive) problem with my 99 gs400, this weekend my battery drained and i needed to get jumped every time i wanted to start the car. i charged the battery, it started fine twice and the third time it stopped mid crank and theres no sounds when i try to crank it not even a click. Does someone know what could be happening? i’m thinking it could be the starter but it could maybe be in theft mode? i’m going to try the lock/unlock trick when i get home from work, hopefully it works!

 

Start by checking/testing the battery (or have an auto store test)... sounds like it's bad.

 

I got the battery tested and its all good. i was thinking maybe the alternator since when it did start after a boost, i went for an hour long drive and it didnt recharge.

 

If you keep guessing, you'll more than likely spend more money throwing parts at it than needed. Get the alternator tested. Almost any auto parts store will do it in the parking lot... Diagnosing the problem correctly is always the better method. :-)

 

I bought a cheap ELM327 and OBD2 fusion on my iPhone and it shows voltage.

 

How many volts? Should be 12.4-ish with the engine off, and 14.5-ish running.

 

Yes i know and i don’t want to throw the parts cannon at it, but it’s kind of hard getting the alternator tested when the car doesn’t want to start.. i am recharging the battery again to see if it starts and i foud out that my starter relay has already been tampered with by one of the previous owners.

 

sounds about right but depending on the charge the battery has the alternator output might drop so it doesn’t overcharge

 

The general rule is a problem starting is battery related and issues while it’s running are charging related. Some times that means alternator, some times the charge isn’t getting into th battery from the alternator, and the battery cables or terminals are damaged or corroded. Take the battery to a parts store and have them test it, I’d it tests good, have them check the acid to make sure all the calls are full, then put it on the slow charger for several hours. Once u know the battery is correct, the car should fire right up, if it doesn’t, u have a starter or immobilizer issue. If it does fire up fine, and your able to drive it, a bad alternator will be apparent after u see the battery light come on in the dash, right before it dies completely and if u jump start it, it will die soon after the jumper cables are unhooked.

 

Some simple at home testing methods would be to start it up, then pull the NEGATIVE battery terminal off the battery. A good alternator will provide plenty of power to feed the engine and it won’t miss a beat. A bad or weak alternator will not be able to sustain the ignition system and it will die almost immediately. If u pull the cable and it keeps running, then u can use a basic, inexpensive set of jumper cables to diagnose a bad battery cable. Many cheap jumper cables are 2 separate cables and the positive and negative cables aren’t attached to each other like they should be. So u can run a good cable from the output on the alternator to the + battery battery terminal, and if that doesn’t help, try the - battery terminal to the engine block, and with the other jumper cable, the engine block to the chassis.

 

Thanks a lot for all the response! The car is “fixed” i still don’t know why it did it but it runs good now. I charged the battery, removed the starter relay and put it back in and it started after! i’ve been running it for 4 days now and its still going strong.

 

I would recommend picking up a new relay in case this happens again. Relays can be a little touchy, and that was a hint that yours is getting weak. Buy one but don’t install it right away. If u have another problem, u will be ready to fix it once and for all. If u haven’t had any issues after a month, just return the new relay and get your money back.