Ok, I need to use the brains of my fellow CL members.

For the past week my car has had trouble starting. It was very weak and would take longer than normal to turn over. I figured this was a battery issue. A few days later the car wouldn't start, but would try to turn over ... i just kept turning the key and eventually it started. Now i know i need a new battery.

I go buy a brand new battery from autozone, install it, and the car instantly starts perfectly, like new. I come back to the car about 5 hours later, and it wont start or even try to turn over. The interior lights are very weak and flickering, the radio wont get enough power to turn on etc....

This battery is brand new, and was shown to work. I am pretty sure this is a Alternator problem. Am I correct? Also, if this is a alternator issue, did I mess up the battery? ... because at one point it started the car fine.

Side note: I have had a stereo system with a 400 watt amp hooked up and running for the past 3 years, and recently noticed that when the bass is turned up, the headlights would dim drastically when the car was running.

I am very limited in my knowledge in this area, and would appreciate any input on this matter.

Thanks a ton! I can always count on the members of this board to know everything in the clutch.

 

bad ground is also causing the battery to drain faster. Get an Optima Redtop battery and get a good ground enhancing kit. That would help solve some the things you see with the ground.

 

ok, but could a bad ground really drain a brand new battery in 4 hours?

 

Your battery is probably just fine. Simply remove the terminals and reinstall them. Make sure that you CAN'T move the battery cables once tightened. Sometimes the terminals get stretched and will not make contact like they should, if this is the case then simply use some pliers to bend the clamp tighter.

I had the same problem with my SC after having the battery replaced.

 

I've tried pretty much everything I can think of in terms of moving the cable, tightening them, making sure the ground is good.

Is there a chance that the battery is just bad?

The weird thing to me, is that after I first installed the battery, the car started up no problems whatsoever ... but then a few hours later ... dead as a doornail.

Some kinda power is going to the car though, because the dome interior lights will turn on, but they are only like 10% of their normal brightness.

 

get the alternator cheacked out .if thats not the problem something is draining the battery .or something can be grounding

 

Update: I got the car jumped, and drove it to an Autozone. They tested the battery and said it was fine. I then took the positive cable off of the battery terminal, and the car did not stall out or shut off.

This would lead me to believe that both the alternator and the battery are ok.

I just shut the car off, and will try to start it in a few hours, hopefully all goes well.

The guy at Autozone said maybe it was my starter selonoid. Does this sound right? How would I know?

 

I would have said your starter, but it wouldn't account for the dimming of the lights or the radio. The starter going out would generally be an intermintant "start" or "no start" situation.

I'm guessing that it is still your cables and connection. Think about it, if you were able to Jump start the car and the battery tested good then it has to be something between the battery and the connection.

Perhaps the top connections on the batter are damaged. I had an instance with a Yukon that had dual poles (top and front connections). When we tested the battery from the top connections it tested fine, but the front connections were broken. Causes MUCH confusion until we figured out what was going on.

 

What ended up being the solution here? Still looking for a way to get my 1993 SC400 to "Rise from your grave!", as it were. Similar problem with the intermittent start / sluggish start problem and working Battery / Alt.

I'm looking for any and ALL solutions to avoid the DREADED (and prohibitively expensive at over a grand) SC400 Alternator replacement.

I love my 400... but DAMN I wish it had the starter placed like the 300......

 

the dimming could mean your alternator is going bad after years of working really hard.
see if the car starts up by bypassing the fuel pump control module by connecting the fp and b+ ports with a paper clip or something. These ports would be located at the diagnostic port on the engine. Do this especially when the engine does not want to start.

 

DO NOT LET ANYONE REMOVE A BATTERY TERMINAL WHEN THE MOTOR IS RUNNING!!!! On a computer controlled car this can cause a power spike and pop a computer or one of the main fuses. Pulling the battery terminal is a good trick on old non-computer controlled cars. I have replaced several computers and some main distribution blocks after a “shade tree mechanic” did this. It sounds like a parasitic draw. Something is pulling power from the battery when the key is turned off. There could be high resistance on the ground side but I would look for a draw first.