I have a 2001 Dodge Dakota 4X4 4.7L and I have never had a problem with it starting. The battery is 10 year old and the truck has 120,000 miles. Last night i got in it and as i turn the key i heard a pop and the truck was dead. I was able to jump start it but as i drove to get home the volt meter spiked to it highest limit. The Check Guages light came on, so i pulled off to the side of the road. As i sat ideling there the volt meter went back to normal and the Check Guages light went off. I began to drive again and the voltage went back up and the light came back on. When i got home i turned the truck off and tried starting it again. There was absolutly no juice in the battery.

Can anyone help??

 

Welcome to DF
I would start with a new battery first, But I will move you post to the section that may help you.

 

Tossup. Id pull the battery, and Alt, take em to Autozone/pep boys etc to see thier test results. Id vote alternator...battery wouldn't create more voltage...could just be a fake reading.

 

I'd vote battery. They don't last forever. It may be shorting internally.

It acts as a big capacitor in the system. It can cause electrical problems.

 

A battery is not a capacitor. Mine just went, literally, 2 days ago. I know they dont last forever. Mine was just about 8 yrs.
They do not retain voltage and puke it out in spikes. Alternators do however, create voltage, and if thier internal regulator dies, which is semi-common, it would create a reading above the 12-14V 'norm'.

Maybe we will actually see a post #2 to see!

 

10 years you sure on that?

That would be a record most fail every 4 to 5 years you must be very lucky or you don’t drive the truck all that much.

Sounds like

1. Battery finally failed
2. Charging system is not working correctly
3. Other electrical problem in wires power block just other things could be a number of things.

Have the charging system checked first like the alternator because if it’s bad a new battery just may get damaged.

 

First things first, you need a new battery. Even before any of this happened, you needed a new battery, you were running on borrowed time, voltage and amperage for a while.

Batteries do act as load in the charging system (not a capacitor though, as stated above), in fact years ago back when batteries were made a lot better and stronger, and electrical systems were not as complex, the battery was used as the sole regulator in the charging system.

If your alternator was throwing higher voltages to a good battery, it would eventually kill the battery but it would hold charge for a while, since you can't even crank your engine, your battery is shot, and I'm betting it's the reason you are seeing the higher voltages. The fact that you can jump start it points directly to a bad battery.

Start with a new one, it's a simple and cheap first step, and you need one anyway. After you hook it up, start the truck and see what your voltage gauge does, idling and driving. Or hook up a meter to the battery and bring the RPM's up by hand and watch what kind of voltage it throws out. If it's still high, the internal regulator is most likely shot and you probably need an alternator as well. High voltage is usually the internal regulator, and low/no is usually the internal diode trio (bridge rectifier) or brushes.

I'm not saying there can't be other things going on, but best place to start is new battery and check your alternator voltage output.

Let us know.

 

Agree with Dakmm... Battery is the culprit.

 

Battery's life all depends on climate. My battery in my truck is going on 8 years It can sit in feezing temps all week long and show no signs of being weak when I do start it(knock on wood) Batterys are weird they can sometimes just commit suicide with no signs of it. Even a brand new battery can too. Im betting its got a short in there somewhere. Autozone,napa or advanced will test it for free.

 

I didn't say it IS a capacitor, I said it "acts" as a capacitor to absorb transients. What does a capacitor do? It stores small charges of energy. What does a battery do?

FYI, the regulator is NOT in the alternator, it's in the PCM.