Alternator toast?

[ninjazombiemaster]

My car had been driving kind of weird, stalling a little, and the head and dash lights would flicker when driving. This got worse and worse, until it was borderline undrivable, difficult to start (today it didn't start, dead battery), and running headlights seemed to make it worse. Rock Auto has several Alternators between 50-60 amps for about $30+shipping less a core charge, should I choose to send one. I could be mistaken, but I'm most likely on the 40 amp stock alternator.

Does a dying alternator fit the bill for all this? And does anyone have a specific recommendation on the new unit? I'm not paying $100+ for an MSA one, though if I'm not already converted, it is my understanding I'll either need to purchase a external to internal regulator conversion kit, or rewire it myself in order to prevent the car from not shutting off / dying slowly from a trickle.. though I'm sure there are plenty of threads on that already.

[Zed Head]

The flickering sounds like my Pathfinder alt before it died. But you have an external regulator on yours. You might just need a new regulator, your alternator might be fine.

And your stock 73 alternator should be either 50 or 60 amps, by the FSM specs. If you already have a 60 amp, then switching to internally regulated won't get you much, if all you need is a regulator.

Not positive, but I think a bad regulator can drain your battery also.

[ninjazombiemaster]

One extra note. If the car is running, my amp meter sits dead center. Running lights, etc, push it left like normal. Normally higher RPMs pushes it to the right. However, it won't move right past the center line at all. If I idle and rev my engine really high, it goes crazy and the meter flies all over its range.

[Zed Head]

Auto stores can check both separately if you take them in.

[Captain_Zeros]

If the ammeter goes to the left of zero, you need a bigger alternator in my book. I've got a used 280zx alternator and it runs everything like a champ. "rewiring" to use an internally regulated alt is wizz easy, it's literally unplugging a connector and jumping the correct wires to each other in the chassis harness (early cars like ours like to have a diode in there to make sure the engine turns off when you take the key out, about a dollar at the local radioshark) . The 280zx alternator conversion kit plug does the same thing and looks sexy doing it, but it's not strictly required for a functional setup.

Edit: pictures of all my car's wiring modifications to run a 280zx alternator. The blue weatherproof connector on the white wire is just because it ripped out of the 6 pin harness connector and that was easier than trying to shove it back in.

Edited July 13, 2013 by Captain_Zeros

[ninjazombiemaster]

Yeah. I was gonna have it checked this morning, and then the battery died.. hah. So now its stuck in my parking space until I can find/buy a huge extension cord, or get lucky and maybe it turns over enough to start.

Edit: Ninja'd the ninja -

If the ammeter goes to the left of zero, you need a bigger alternator in my book. I've got a used 280zx alternator and it runs everything like a champ. "rewiring" to use an internally regulated alt is wizz easy, it's literally unplugging a connector and jumping the correct wires to each other in the chassis harness (early cars like ours like to have a diode in there to make sure the engine turns off when you take the key out, about a dollar at the local radioshark) . The 280zx alternator conversion kit plug does the same thing and looks sexy doing it, but it's not strictly required for a functional setup.

I agree. typically when driving it stayed positive, but idling or driving at low RPMs for extended periods with a lot of things going on pushed it in the negative. Its been a nuisance, which is why I'm going bigger with the repair.

Edited July 13, 2013 by ninjazombiemaster

[71Nissan240Z]

Test the output voltage at the alternator before the regulator. That should tell you what needs to be repalced

[ninjazombiemaster]

Sounds like the smartest course of action is to charge it somehow and try to test it. In the long term, I'd like a bigger alternator, but right now my focus is getting back on the road, so if that means a new regulator, then so be it. They run about the same price on RockAuto. I'll check on my setup after I get off work and make sure I even have an external regulator. I'll post a picture, too.

[Captain_Zeros]

If you can't find a long enough extension cord, carry your battery inside and charge it near an outlet :ninja:

I would strongly suggest the 280ZX distributor, mechanical voltage regulation is pretty objectively terrible from a performance standpoint.

[ninjazombiemaster]

If you can't find a long enough extension cord, carry your battery inside and charge it near an outlet :ninja:

I would strongly suggest the 280ZX distributor, mechanical voltage regulation is pretty objectively terrible from a performance standpoint.

Perhaps long term. But this is my only vehicle and I need it back on the road yesterday. At least manually charging it should suffice for the weekend.

[71Nissan240Z]

If u need a step by step to test the output voltage before the regulator I can provide that too.

[FastWoman]

FAIW, running your battery down that far sucks much of the life out of it and can possibly kill it. You shouldn't try starting your car on a weak battery. Charge it first.