eating batteries, and or starters

[ForTiLLiaN]

92 explorer XLT
When i first got the truck, it had a normal battery and alt.
I put in a 160amp ALT. and a stereo and it worked fine.
Later on i put a 4mo. old red top in it, and about 6 months later the red top and the starter went out. This was in sept of 04. So i bought another red top, and another starter from autozone and this morning i went to go start my truck and it wont start. I noticed last night when i got outta work the start sounded kinda week. Well this morning it doesnt want to turn over, it tried 2 times, and after that theres not enough juice to turn it, just clicks. I believe i have a warranty on both the starter and the battery. But im wondering what is killing them is such little time. I have a large stereo, but i would think my alternator could keep up with it. I have an alarm as well, but i dont think that would kill it. When im driving my volts stay right under 13.8 and when its off there right around 12.

Thanks for any input

 

[jim blair]

You might use a digital voltmeter to see what the voltage is at the battery with the engine running and your stereo playing. Some times the voltage delivered to the battery is not the same as indicated on the gauge in the dash. First measure the voltage at the battery with the engine off. Then start the engine, turn on any other assecories that you use alot and see if the voltage drops. Also see if the voltage rises much if you increase the rpm to 1500 rpm or so. If you have good voltage being delivered to the battery then the starter or it's conections are probably the problem.


If a digital meter at the battery is dropping low at idle with everything running and you idle very much it will slowly suck the battery down. If your voltage is dropping too low at idle it might be the cables dirty or a poor ground conection. you can turn the engine off measure the resitance, (ohms) between the engine and the battery ground post. Then measure resistance beween the starter case and the engine block. These readings should be zero ohms or real close to it.

If there is much resistance at all betwen the ground side of the starter and the battery, then, according to ohms law the there will be a voltage drop across the resistance that will subtract from the voltage of the battery. The this will lower voltage will make the starter work harder and eventually burn it up. It is same effect as using a really long extension cord on a power saw, it will seem to operate but it really is working way too hard and won't last long.



Back in the early 80's I once had a Chevy with a 396 that ate starters every few months. I had put in battery, altenator, cables, and voltage regulator all at once and a couple weeks later it wouldn't start one morning. I was going to school to be an electronics tech and I was stumped as how it would fail to start after putting all those new parts on it. I thought the car was posessed. I took a copy of the wiring diagram for the car to school with me and asked the teacher what his approach would be. He said to measure the voltage drops and resistance of all the wiring and components and the answer has to be there somewhere.

I measured the voltage at the battery with the engine running and it seemed to be charging good. I ohmed out all of the circuit and found the starter wasn't grounded very well. I took the starter back to the place I bought it from and they tested it and gave me another one. I made a grounding strap to run from the engine to the fire wall. Then I used sand paper to make the starter mounting surface and block mounting surface reall cleann and shiny. I put it all back together and now I had zero ohms from the ground battery post to the starter case. I never had anymore problems with car starting again.

I know this is kinda long winded but I hope it helps.

 

[ForTiLLiaN]

what is the best way to find an oil leak? Recently i developed a small oil leak, it will leak about 1 quart every 1-2 months. I noticed on the starter that the connections got hit with oil pretty bad. The oil grime starts just about the valve covers. So i guess i would start there and replace the valve gaskets, and other ideas on what to look for would be great.