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1st generation charging problem

Discussion in 'General 4Runner Talk' started by climbon, Jan 8, 2017.

  1. Jan 8, 2017 at 2:29 PM

    climbon [OP] New Member

    Jan 8, 2017
    First Name:
    1988 4Runner
    Hi all. I am new to the forum. I have a 1988 4 cylinder 5 speed. It has about 250K on it and generally runs well although burns through a little oil. My main problem is the charge warning light has come on recently. The battery is definitely not getting sufficient charge. I pulled and fully charges the battery and fixed a loose negative terminal battery cable end (ground strap). I tested the output of the alternator with a multi-meter and it showed almost 14 volts. Can anybody help me get right to the problem or suggest a step by step procedure to resolve this? Thanks in advance! Ken
  2. Jan 11, 2017 at 11:35 AM

    TN_TRAIL New Member

    Dec 24, 2016
    First Name:
    2017 TRD OFF RD PREM
    oh the list....!
    Hi Ken,
    Sounds to me like you took the right steps. Got a couple more fairly simple suggestions. First, with the battery fully charged, check your alternator output with all accessories going full snot. (lights, AC, etc.) IIRC, it should be reading about 14.4V measured at the battery terminal. Second, did you load test your battery? (these can be had cheaply enough at Horror Fright, and are indispensable IMHO). To use it, with the battery fully charged, (and you should actually wait about 24hrs after a charge cycle for an accurate test), mimic a full ten second load test on the battery, while noting where the meter drops to during the load. Then I repeat it again. the reason is that a "weak" battery MIGHT pass the minimum voltage test the first time, but the second one seems to always (so far for me) show the battery's impending death in the near future, and should be replaced. OK, now, IF the battery is bad, (and it could well be, since you found a loose ground that would limit the proper charge current from reaching the battery) make sure to thoroughly check the charging/regulator action of your alternator as well. I have had a bad regulator in one years ago that nearly drove me nuts. (similar symptoms) Good luck, and post your findings.

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