First off this car has a new battery, starter, coil, plugs and wires.

I can't let the car set for 48 hours without starting it because the battery loses all charge.

When the car is running the voltage gauge fluctuates up and down like it isn't getting a consistant 12 volts.

How can I tell if anyone ever put underdrive pullies on the car?

Something is dragging it down and I haven't got a clue what it would be.

Any ideas?

 

Could have under drives,but I wouldn't worry about that yet. Take the alternator off and have it tested,if its good then put it back on and make sure its actually charging,if not your gonna have to chase wires.

 

first thing to check for is hook a dvom up in series with the neg battery terminal and ground post on battery and set dvom to amps and check draw with all doors shut and lights off and hood lamp un plugged if it has one, draw should be between 25-50 milliamps at rest

 

Like they said above test the alternator, might be time for a new one. Do you have it alarmed? Are you leaving something on when you park it?

 

If it is draining over night there is a short somewhere that is pulling power while the car is off.

 

You dont have a CHARGING problem... you have a DISCHARGING problem.

Go read up on diagnosing Parasitic Power Losses

 

Your right Adder it is a discharging problem.

Also, no it doesn't happen over night. It happens after the car has been sitting for a couple of days. If I use the car every day it is fine. But the past couple of days I've used my other car and sure enough the battery was dead again.

The last time it did this happened to be at a shop and they said they checked the output of the alternator and claimed it was putting out the correct voltage. Though I still plan on having autozone put it on their machine.

No there is nothing on when the car is off, at least as far as I'm aware. Stereo, climate controls, etc. are all off.

 

same thing happened to my bronco, if you drove it every day, or every other day, it would be fine. but if you let it sit for like 4 days, the battery would be dead.

ended up being a stripped power wire touching the oil pan/block/k member. cleaned it all up, covered it, and secured the wire away from anything it could rub, and the problem was gone.

 

why does it have a new battery ??? did you test the battery ? and was it doing it before ??

you can tell if you have underdrive pullies easiest by the size of the crank pulley. UD's are tiny.....stocker is as big as the balancer, but the UD is about 2" smaller i'd say

 

do like mjr said and check it. I usually take a test light and touch one side to the neg battery post and the other to neg battery cable. If it lights up, you have a drain somewhere. Then start pulling fueses and checking things like the light in the trunk. If everything is in spec, you probably got a bad battery....It does happen.