1JZ alternator issues

[ronnie4]

When I first start my car the voltage reading across the batters is about 14.5 volts. After driving for 5 minutes or so it will drop to around 13.1 volts. Is this normal or is my alternator going out? The battery light is on all of the time when I am driving. Thanks in advance

 

[ronnie4]

Update: Just drove it and the headlights and lights seem to dim when the electric fans are on, when I turn them off the lights get brighter and engine rpm's increase slightly. I guess this seals the case that it's the alternator.

Is it normal for the alternator to ot have enough juice for all of the accessories or is mine dieing? I want to say the stock 1J puts out 90A and I remember the one on my old civic was 65A and it had enough juice for everything I ran on it including a high amp stereo system.

 

[JustinGotA1j]

Sounds like its not working too well. On my 1j it did the same sort of thing so I replaced mine with one from a lexus sc300 (92-94) which is direct bolt on plugs and everything and its 110 amp to which is even better.

edit: before replacing the alternator take your battery in and have it checked out. most places will do it for free

 

[tissimo]

Your alternator light shouldn't be on if its producing 13.1v. You have issues with your wiring I assume.

 

[ronnie4]

Your alternator light shouldn't be on if its producing 13.1v. You have issues with your wiring I assume.

Even when I am reading 14.5 volts across the battery with a multimeter the gauge only shows 12v. I assume this is a problem with the wiring to the gauge? Anyone know which wire coming into the cluster feeds to the gauge?

 

[tissimo]

I assume you ran a seperate wire to the battery for the alternator (not using factory wire) so check your fuse box power wire. It might be worn and have some broken wires at the connector (seen a few times).

 

[ronnie4]

I assume you ran a seperate wire to the battery for the alternator (not using factory wire) so check your fuse box power wire. It might be worn and have some broken wires at the connector (seen a few times).

You talking about the one that goes to the from the alternator to the fuse? Checked that one and it's fine. I'm thinking it has to be the wire feeding to the gauge, anyone know which wire it is?