Alternator problems :(

[Moph]

My Sierra has me stumped. I'm running a 100A EF Falcon alternator with a 6 month old RAA Premium battery (decent heavy duty) and am on my third alternator in 3 weeks

It's possible that alternators 2 and 3 were duds straight from the wreckers - dunno. I've fiddled with wires and am pretty sure I have the IG and L wires hooked up correctly as the in-dash battery lamp comes on with ignition on then turns off once the engine fires up. Both IG + L are at battery voltage when disconnected from the alternator and ignition is on.

But I'm just not getting any charge. Alternator light isn't coming on when the car's running or anything - I just don't get charge. Am having to put it on charge every night at the moment (or push start the damn thing everywhere) but am getting sick of changing alternators.

Any idea where the problem could lie? I'm worried something I'm doing is blowing these blasted things but I can't work out what.

[-Scott-]

Does the body of the alternator have good continuity to ground?

[Moph]

Yup - 2G cable from alternator swing arm mounting bolt to battery negative + 100A earth strap to body + normal bolt/mount connection to block. Should suffice

2G from B+ to battery also.

[-Scott-]

Sounds good - have you actually measured the electrical resistance?

Can you take some voltage measurements?

[ethann]

My Sierra has me stumped. I'm running a 100A EF Falcon alternator with a 6 month old RAA Premium battery (decent heavy duty) and am on my third alternator in 3 weeks

It's possible that alternators 2 and 3 were duds straight from the wreckers - dunno. I've fiddled with wires and am pretty sure I have the IG and L wires hooked up correctly as the in-dash battery lamp comes on with ignition on then turns off once the engine fires up. Both IG + L are at battery voltage when disconnected from the alternator and ignition is on.

But I'm just not getting any charge. Alternator light isn't coming on when the car's running or anything - I just don't get charge. Am having to put it on charge every night at the moment (or push start the damn thing everywhere) but am getting sick of changing alternators.

Any idea where the problem could lie? I'm worried something I'm doing is blowing these blasted things but I can't work out what.

I feel for your brother!

I don't having any reds when I start my car, This arvo I'm checking the bulbs because I was told that thats part of the charging system.

[chimpboy]

I've fiddled with wires and am pretty sure I have the IG and L wires hooked up correctly as the in-dash battery lamp comes on with ignition on then turns off once the engine fires up.

Just to check - how are these two connected then?

[Moph]

No probs re resistance Scott - all cables have good continuity. That doesn't mean of course that they might not have burnt out all but one last strand of copper that is keeping the readings good, but it's unlikely.

Voltage measurements - yes have done, but haven't found anything useful. Basically IG and L are at zero volts with ignition off; battery voltage with ignition on but engine off; with engine running IG stays at battery voltage (slightly lower actually as it comes off the loom somewhere within the car hence has 0.2-0.3V drop) and L stays at battery voltage but the alternator internal circuitry cuts the circuit meaning the alternator light flicks off. B+ is constantly at battery voltage no matter what - no charge.

Not quite sure what you mean with your query chimpboy. For those who know EF/EL alternators, I have L (red/white) hooked up to the top-most alternator pin, nearest the B+ terminal and the IG (black/something) hooked up to the bottom most alternator pin.

Am thinking I might buy a recon'd eBay unit ($165) so I can at least be sure the alternator is fine, and the seller should be able to confirm for me that the pinout is as I have assumed.

[chimpboy]

Sorry, what I meant is that afaik, these alternators want one wire via the ignition lamp, and the other direct to the battery by essentially the shortest route possible, as a voltage sense. So I was trying to double-check exactly how you had them hooked up.

They don't, I think, need to go to the ignition switch because they get their ignition signal via the lamp circuit.



This image came from a page that came with a brand new EF alternator my old man bought (or maybe EB... can't recall).

I don't really think that the 0.2-0.3V drop you've mentioned should really matter though, and in theory it would cause your alternator to do too much, not too little, so it is probably not worth getting into I guess.

It's a rather odd problem and I am afraid I have no more thoughts at this point!

[Moph]

Thanks chimp - I note that diagram warns against reversing S (IG in my terms above) and L as it will destroy the warning lamp circuit - perhaps I've blown the warning lamp circuit. The general word in the Suzuki section was just to try the wires one way, see if the lamp lit, and change them if it didn't. May be wrong advice there....

Did just notice another symptom - I usually baby the Zook around, changing at around 3500-3600rpm. I had reason to plant the foot this avo and noticed the alt + handbrake lights came on when I revved it hard. Repeated it a number of times and found that both these lights come on when I rev over 4500rpm odd and stay on until revs drop below 4500rpm

I think I'm just going to accept that I've fried yet another alternator, buy a reco one with the pinouts marked on it, check the Zook wiring diagram to be 1000% sure I'm hooked up correctly, and see how that goes.

[-Scott-]

The lights on/off you describe sounds like the regulator isn't doing it's thing - which is possible if you've "destroyed the lamp circuit". Can you buy a replacement regulator by itself?

[chimpboy]

For what it's worth, the regulators are the same on the commodore alternators of the same era - VP or so. So you could get one at a pick-a-part for stuff all if there is one nearby.

[Moph]

Grave dig for future reference by others. Found this in a search re something else and thought I should update as to the solution. Wasn't the alternators at all ... was the pulley slipping on the shaft Hence the alt light coming on at higher revs. Had to swap the multi-V Falcon pulley for a V-belt one and in each case (with the alts I thought weren't working) it was likely the same problem. I was tightening them by hand - didn't have a torque wrench.

Net result of the above stupidity is that I have one new aftermarket alt fitted plus both a new and second hand alt sitting on the shelf as spares

C'est la vie...

[Foo on patrol]

Well there you go! Did you give yourself an upper cut?

[RAY185]

So you were using a V belt on a multi rib pulley?

[-Scott-]

No, he wasn't.

[RAY185]

Wow I read that wrong huh. Oh well I had a chuckle anyway. Bourbon must be kicking in. Bottoms up!