Bad Alternator Diodes? (1 Viewer)

[Eporter]

The Brake light on my '83 FJ60 was flickering, and the charging gauge dropping down below 12v, so I just had my alternator rebuilt at a local reputable rebuild shop.

Got it home, reinstalled the alt, fired up w/ gauge at ~16v, shut off for the night. Next day went out, battery completely drained, just got the dimmest of dash lights glowing when the key was first turned on.

So, I charged up the battery and reconnected the alternator. As soon as I reconnected the battery terminal, I could hear the click/thunk of the starter solenoid. Get in truck, turn key (don't hear the click/thunk) and it starts up. Gauge is at ~16v.

Is this normal? I always thought I heard the click/thunk when the key is turned to the on position. Is a short in the alternator causing the starter solenoid to click open(shut?) and then stay powered, thus draining the battery?

I don't remember if the click happened the first time i hooked the rebuilt alt. back up. And I managed to blow the fuse in my multimeter, so...

Thanks for any advice, it's been awhile since I've been on here.

 

[OSS]

Nothing should actuate (click on) when connecting a new battery, especially not the starter solenoid.

I'd rule it out by making sure all accessories are returned off, key out of ignition, then disconnect and reconnect the battery terminal. Nothing should happen.

If you're definitely hearing the starter click when the battery is reconnected, there's something wrong with the ignition switch.

A battery can be permanently damaged if its discharged too deep just once. Recharging it will get its volts back up, but it won't have the amps it used to.

Don't trust the dash voltmeter for accuracy. It's just a general guide. If you want to keep track of your volts while troubleshooting, run a wire from the battery to the cab to a hand held volt meter so you can verify what's really going on.

 

[Eporter]

Yeah, the click at battery connect had me wondering.

All tests/noises were done with key removed, all things off, door closed, etc. I tried to isolate the ign. switch by disconnecting the two wire harnesses under the steering column, but the clicking kept happening, strange?

Agreed the dash voltmeter isn't to be relied upon. I mainly just used it to note that with the new alternator it was now reading at a higher volt level.

I guess I'm wondering if this is an example of a "classic" bad alternator problem of letting power bleed through and affect the starter.

 

[morganism]

It's prob the bad wiring setup from the ignition switch back to the starter solenoid. It can jam open, and not even click or turn over.

The solenoid contacts can fry, but that is usually not why tapping starter can get it to start, it is because it jars the contacts on the small wire, and knocks the spindle gear off the high points on the tranny ring gear.

see this,

94 delayed cranking. Starter, ignition switch, or other?

it can also be crappy connection at fusible link connector, the big green cyl coming off the batt positive. Those contacts need to be cleaned and buffed regularly, so it doesn't fry just from increased resistance in the contacts.

 

[Eporter]

I'll have to look into the starter & wiring. It's weird that this happened right after the rebuilt alt. but that's how it goes sometimes...

I def. had a starter issue where I had to tap it with a hammer about a month back. Previously I've had some no start issues with no click/crank/whatever. It's like all these clues are pointing at something!

 

[Eporter]

So I took out the alternator & had it tested at the rebuild shop. They said it tested all good.

Put it back on, and it seems like I've got 12v power coming from the alternator harness plug? With battery connected, I can connect the B+ terminal on the alternator, and nothing happens. If the harness is plugged in, & I connect the B+ harness, I hear the starter clunk/thunk?

Seems like an ignition switch issue?