starting problems

[teppei286]

maybe its because i live in michigan and its crazy cold here sometimes but ive been having this problem. my battery keeps dieing overnight i guess or when it sits all day. Ive gotten the batt tested and the alternator tested both came out perfect. Even after i got the bat fully charged at a near by store and i turn the car on, the bat meter jumps depending on what i turn on. It goes from 14 to under 12 if i turn on the defroster, lights, rear defrost which is the worst. i really dont know what to do. Also at times when im driving or reving the engine you hear a whistle noise come from the alternator area. Not a screech but more a loud whistle.

any help or input would be greatly appreciated
ty

[hermesbooking]

I just went through some of the starting issues. Changed the Alternator, that was a huge problem for me. Check your grounds real good and the cables coming off the battery to the starter. If you have some corrosion on any of that stuff, it will mess up your day. I went through all my ground points, cleand them and sprayed with a corrosion preventative, and went through my cables. Hope this helps a little.

[Eldorado]

what alt did you put in, hermes? oem? or aftermarket?

[Razorback1980]

Looks like you have two posts for the same problem. I'l put my response in both.

Here is how I do it. I take the negative battery cable off the battery. I get a meter with a 10 amp reading and clip the negative lead on the battery post and the positive lead on the battery cable you just took off. This will tell you the amperage traveling through the meter. Should be less than 100 mA. Actually ideal is around 60 I think. Car should not be running and all doors should be shut and all lights off. Anything that should be shut off normally over night should be off. That will give you an indication of how much electricity is being pulled while it's sitting overnight in the driveway.

If the amperage being pulled is about 100mA, then you need to look for something pulling power and draining your battery. With the amp meter in place as described about, start pulling fuses and relays until you pull one and the amp meter reads under 100. That will tell you the circuit that is pulling the power and then you need to start unplugging items on the circuit to find which one is bad. Some of the common things that cause this is the heater connectors on the rear hatch glass and the door light switches that run the light when you open the doors. You might try those two circuits first.

Once you get your battery drain levels down to an acceptable level, the battery will stay charged.

Just thought of something...when running the car, does the voltage read around 14V? It could be the charging wire isn't carrying current to the battery because of corrosion or poor connections somewhere. If the current drain is under 100mA, then start looking for dirty or bad battery cables or the alternator connection on the back of the alternator or the connection on the starter.

The amount of battery drain will tell you which path to pursue.