1998 Mitsubishi Eclipse elecrtical

137,000 MILES
Avatar
RICHIE51
  • MEMBER
  • 1 POST
repaced altgernator jump started car to check volts show 12.5 i kowwhen running it should be 13.8 had i bench tested itpassed but i can't ge it to 13.8 don't know why i can jump start the car ad drive it around the battery light does notcome on and when i get back and shut it off it wil not start it hasa w battery in and starter plus an altenator what could be the problem im all of out ideal need some help
Jul 14, 2013 at 3:08 AM
Advertisement
Avatar
KHLOW2008
  • ✓Experienced Mechanic
  • 41,812 POSTS
Benchtesting is not an accurate means of alternator testing. It can test if the alternator is charging but it does not test its charging capacity.

At 12.5 v, the charge rate is too low. After starting it could be 12.5 volts but it should go up aftera while if the battery was initially weak. If it does not go up, either the alternator is bad or it is not turning as fast as it should be, meaning there could be something wrong with the drive belt or the harmonic damper.

Did you retest the charging after driving around, if it drops lower than 12.5 volts, you know there is something wrong with the alternator and rebuilt alternators are something I do not trust completely.

Jul 14, 2013 at 10:41 AM
Add a reply
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.

Frequently Asked Problems for This Vehicle