i am not sure if my alternator or battery is on its way out but on occasion when my headlights are on the volt gauge fluctuates up and down. sometimes it goes away and the volt needle is well above midmark. other times it drops. i am going to get my battery tested but i would like to know the difference in symptoms between a bad battery and alternator. thanks.

 

Most auto stores will check your charging system for free as they're hoping to sell you a battery or alternator. Do you have any other symptoms like slow cranking?

 

When one goes out, it usually takes the other out with it. It did that in my case, and had to replace both. Good luck, hopefullly you replace the culprit early enough so it doesnt put too much strain on it.

 

it does take a couple cranks for it to start but i assumed that was the 140,000 mile fuel pump that is ready to be replaced by a racetronix unit. i believe the slow cranking really is the fuel pump though because it starts a lot easier with a full tank of gas rather than a low tank.

 

If it was the alternator, you would have a low reading on your gauge and lights and stuff would be dimmer with the ignition in the on position.

 

You mean the Battery right? the alternator is not doing anything with the ignition in the on position. The engine needs to start spinning before the alt produces any volts.

I noticed the wire conecting the Alternator straight to the battery to get a little warm with the engine in Idle. My scanner has detected voltages as low as 12.8 with the A/C on and lights on. To make sure I scanned her while I crancked the engine on and the Battery voltage dropped to 8 volts before she started...


Correct me if I am wrong but my battery is weak or I have a bad conection to the battery. My bat is about 3 years old now and I think its draining voltage from the Alternator. Funny thing is that I did park my car for 7 days recently and I she crancked just fine when I came back. so I dunno what gives.


Marvin

 

Yeah...thats what I meant because if the alt aint working than your battery aint happy.

Your battery lasted 3 years???? Damn thats good bro. I would say shes on her last leg.

 

when myu alternator was on its last leg. Nothing would work properly. The car wouldnt run right it just stumbled around and it wasnt pretty. After it was replaced all problems were fixed.


Later,
-JOhn

 

sometimes when its really low the check gauges light comes on.

 

When mine went bad I got a check gauges light.

 

anyone ever observed the battery voltage with a scanner while revving the engine up?

does it remain steady of drops with RPMs with the Alt its in its last leg?