280z fuel gauge / alternator fuse blowing upon acceleration

[Joey J]

Ok so i purchased the car in February, the fuse blew maybe a month or 2 later i didn't think much of it. I just replaced it with a fuse i had laying around. It didn't even have the correct fuse. 

 

The required fuse is 10A and i believe it had 15A i ended up replacing it with a 20A, it worked just fine until about 2 weeks ago (I didn't know any better, i now know that's a big no no)  This time around i decided to use the correct 10A fuse and it lasted until today and now it blows instantly upon hard acceleration.

 

I blew 3 today... i tried cleaning up the ground wire onto the engine block because i had just replaced all the coolant lines and the ground was removed in the process. That didn't fix anything though.

 

Below is a pick of the wiring. I always wondered what that lose yellow and red wire was pointing down

 

I'm thinking my alternator went bad and it putting out too much power causing the fuse to blow. I'm going to remove the alternator later today and take it to Autozone and get it tested. 

 

Any help is greatly appreciated!

[Joey J]

looks like that loose wire in the pic is supposed to connect to something but i cant tell what it is in the diagram above

[72240z]

Replacing blown fuses with high rated fuses without solving the issue is asking for problems. 

Sounds like the voltage regulator to me. 

[datzenmike]

The extra wire is likely for a capacitor to filter out alternator whine.

[Ranman72]

put a voltage meter on your battery and rev the motor see if it boosts past about 14.5 if it doses alt voltage reg is bad 

[Joey J]

I removed the alternator and got it tested at autozone and advanced auto parts and it failed at both places. I replaced it and at idle the volt meter reads just above 16 volts. (It was in the normal range before the alternator decided to fail)

 

Looks like you all are right the voltage regulator went bad. Luckily I decided to order it yesterday. So I should have it in 2 days. Ill post the results then.

 

Is it possible that the bad voltage regulator damaged the old alternator?

[Joey J]

Ok so I replaced the alternator and the voltage regulator. Checked all the connections and cleaned them. I put a trickle charger on my battery and fully charged it.

 

The charge light stays on when the car is on and the volt meter slowly climbs past 16 at idle. Here's the readings I got with a handheld volt meter testing from the battery.

 

Idle 14.75

Idle and lights 13.21

Idle Lights a/c 12.44

Off 13.4

 

I have no idea what to do now. So confused.

[Joey J]

Tested again with a volt meter and it reads 15 at idle and 15.35 from the alternator itself.