1998 Mitsubishi Eclipse elecrtical

RICHIE51

MEMBER
1998 MITSUBISHI ECLIPSE
137,000 MILES

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

Sunday, July 14th, 2013 AT 10:08 AM

1 Reply

KHLOW2008

MECHANIC
41,814 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.

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Sunday, July 14th, 2013 AT 5:41 PM