Toyota Repair: toyota van repair, fuse block, fuse box


Question
i recently bought a 88 toyota van, i replaced the fuel pump on it and the alternator and the efi fuse under the dash was blown. it now runs but will not charge battery, when i rev the motor to about 3000- 3500 rpm the charge fuse on the fuse block has power( with test light) but not at idle. old alternator charged 11 volts new alternator charged 12.5 volts , manual says 13-15.3 volts are necessary,could it be something making diode in alternator go bad? i've been all over this van and all wiring checks good, relays, circuit breakers, etc. some looseness in fuses in fuse box, should i replace fuse box?

Answer
12.5 volts is not enough to keep the battery charged, have the alternator bench tested, if it checks good you need to look elsewhere for the cause of the voltage drop between the alternator and the battery, you will need a wiring diagram for this. Don't forget the ground side, make sure the battery ground connection is good, can't think of anything that would make a diode go bad, re-check the alternator, it's possible that it had a problem when you bought it.