Question!!!
 

Hey so how do i know if my Alt is bad??? i went to start my car and i thought everything was good...when I backed out of the drive way I noticed that the headlights were a little dim but I thought nothing of it cause the car ran fine a few hours earlier...anyway as i was driving up the street to leave my neighborhood i noticed the radio was going off and on...I thought this was weird....so i shut the car off and looked under the hood saw nothing out of place nothing looked disconnected or broken so i shut the hood and went to start the car back up..it cranked sooooo slow then fired up and shot stright up to 2500 rpms and then dropped to 950rpms then started to surge....what do you think it could be???

sounds like the alt. it's self, you can take it off and have it tested, or could be the battery but i doubt it.

yeah...a few people have suggested I start the car and unhook the battery to see if the car continues to run HOWEVER i'm a little wary of that method.

Why?

I got this from another DSM forum

"P.S. Removing your batt cables while the car is running is not really a good idea, it is possible to "jolt" the computer system with the extra voltages coming from the alt and therefore cooking things that should not be cooked. "

deff sounds like the alternator man. another way to check is if you have a volt gauge, wire it to the alt output and see if the alt is puttin anything out

now would the Alt being bad make the car have a erratic idle??

do not unhook the positive cable with the car running, on newer more advance systems it can fry your ECU.

some may have differant inputs but from my knowledge it can, yes.

your battery ends up loosing enough power to where you spark pulses will slow down and you puel pump will slow. basically when everything starts loosing power, the system will run goofy.

take a meter and put it on the back of the alternator where the reboot is and ground the other end. if ur getting 12.5 to 14 volts the alternator is good