-   4.6L (1996-2004 Modular) Mustang (
-   -   Electrical Issue? I'm stumped (

Kenny_k82 02-20-2012 01:55 PM

Electrical Issue? I'm stumped
I have an 01' GT and I put a new battery in about 2 months ago after having to jump my car (figured it was the 4 year old pos battery). Everything was good for a month, but over the last 3 weeks I have had to jump it at least once a week. The battery tests good and the alternator is good as well. I keep my keys out of the ignition and I make sure everything is turned off.

-It goes dead randomly after sitting overnight, but sometimes starts just fine for 5-6 days and then randomly it won't start.
-It will click when I go to start it or barely crank over and then click
-Starts right up as soon as jumper cables are hooked up
-Had the battery tested at 2 places

So if it were a short wouldn't it drain the battery every night as opposed to doing it in 1 day sometimes and 5 days other times? Battery and Alt test fine and I have had no starter issues at all. Any ideas? Missed class today because of this and it's getting annoying.

shrimperdad 02-20-2012 02:08 PM

I had a vehicle doing something similar to this and it was wire partially broken going to the starter. If the battery is fully charged showing good voltage and it will not start this can be your problem because your not getting enough amps to the starter. If the battery is drained then start pulling fuses to see where the drainage is coming from with a volt meter.

Kenny_k82 02-20-2012 02:16 PM

It starts fine when the battery is fully charged, I don't own a volt meter and I don't know anything about electrical problems. I'll try to check the wire going to the start but it Might be time for a shop I guess...

cliffyk 02-20-2012 03:51 PM

How many miles a day do you drive, how long is each trip, at what speeds?

How was the battery tested? Was it a 15 to 20 second high amperage, 100A to 300A load test or one of those silly little handheld things used by the FLAPS--if the latter then it wasn't really tested...

Kenny_k82 02-20-2012 04:34 PM

I drive about 25 miles a day with speed from 35-55mph. I had it tested on a handheld at Walmart, didn't trust them so I brought it to Napa and they did a quick test and then put it on the machine for a load test for 30min and it tested good.

cliffyk 02-20-2012 06:57 PM


Originally Posted by Kenny_k82 (Post 7847179)
I drive about 25 miles a day with speed from 35-55mph. I had it tested on a handheld at Walmart, didn't trust them so I brought it to Napa and they did a quick test and then put it on the machine for a load test for 30min and it tested good.

Well that should be plenty to keep it charged. Do you have any aftermarket accessories (alarm, radio, ???) that might be drawing power even with the key off?

One other test to perform is what is commonly called a "dark current" test, see page 414-00-10 of this document, Battery--Drain Tests...

Kenny_k82 02-20-2012 07:40 PM

That's the odd thing. I've never had any sort of electrical work, stereo work, or mods requiring any kind of electrical modification and I have had the car for over 2 years with no issue and then all of a sudden this started. The radio, amps, everything is stock.

Kenny_k82 02-20-2012 07:46 PM

Ok, so I could be nuts, and let me know if I am but I made an observation. The car had no issues for a full week until this morning. During that time I was making sure that I turned off the radio and heater before shutting off the car and pulling out the key. When it was dead this morning I noticed that I left the radio on before shutting off the car and taking the key out of the ignition. It's the only thing I can think of that I did differently, but is there any way that could make any bit of difference?

trexflyer 02-25-2012 02:06 AM

I had the same issue with my explorer a few yrs ago. Replaced the starter cable/wire and everything was fine. Battery was an old pos so replaced that. 2 months later replaced the starter and everything was fine for another month or so. Thinking that it couldn't be the new starter wire, and everything else was replaced I was stumped. Turns out the old battery corroded the inside of the new wire in 2 months and that ended up being the main culprit (again).
I guess it's possible the remote power lead going to the stereo amps is causing them to stay on all the time? But that would involve other issues with the radio/wiring as well. My random starting issues were just that....random. Sometimes it would go for over a week starting fine, other times I needed a jump right after turning the car off n driving for 200 miles.

Kenny_k82 02-26-2012 11:33 PM

I was cleaning my car today and noticed something odd. They key was out of the ignition. I sprayed the radio and wiped it down and when I hit the buttons the radio came on, just the display trying to eject a CD. I don't think it should have power with the key out of the ignition, might be the culprit!

All times are GMT -5. The time now is 02:23 PM.