So I have a 1988 subaru gl wagon and it is having charging issues. As in the alternator is not charging the battery. I have replaced the alternator twice as well as had my old one tested (it tested at 14.5 volts). I have replaced the battery, and have taken off and cleaned all the grounds battery terminals, and plugs to and on the alternator. Whenever I test the alternator output it is the same voltage as the battery. Whenever I rev the engine above 3000 rpm, all the error light come on (charge, break fluid and stop lamp) just like when you turn the car to the on position. Thought it could be the ignition switch so replaced that and still nothing. Any suggestions? I am out of ideas.

What voltage readings do you get on the battery while at idle, and revved?

 

What I have seen on my GL / loyales is when one of the brushes in the alternator wears to the point of loosing contact with it's slip ring, the dash lights glow dimly at first, then eventually, it's not unusual for a number of them to glow.

 

The wiring involved with those lights is in the 2 pin connector.  There are at least 2 other connections in the wiring between the back of the alternator and the lights.

Hey Gap, I didn't know there was another one of us in Colville. So am I. Check continuity through each wire for the plugs. It may be a broken wire that looks fine but isn't. Like GD says, don't troubleshoot a rig with Visa. It is going to be something simple and something that is just being overlooked. Plus when you rev it, it seems like it is losing whatever voltage it may be getting before the rev.

 

What do you mean Tested? Did you take it to Oreilys and have them put it on the machine? Like DaveT said, it might be loose when you rev. 

Edited March 1, 20179 yr by Naked Buell

Make sure you compare readings at the alternator and at the battery posts.

 

It also could be a bad diode.  Check reading at the alternator for the AC current.

 

Good luck,

Sam

Had my alternator taken out and tested at orielly as well as having orielly and Walmart do a system test and none of the tests suggested the alternator was bad. Whenever I check the voltage Wether at the battery terminals or at the alternator, it is the same (within .01 volts) at 12.6. Checked continuity between the alternator and the battery and it read .1 volts, which everything I have read says it has to be over .2 volts to be a wiring error between the alternator and the battery. Where else can I check?

Hey mine did the same thing. got it figured out, something that we tend to overlook. You need a better ground. i have 3 ground straps on mine. since doing that it solved my alternator not charging issue. thought it was a positive current problem, ended up being not a strong enough a ground.

12.6 confirms that it is not charging. Especially at both locations.

 

Possibly ground, possibly 1 of the 2 wires or the circuit feeding them is open.

also make sure bearings on pulleys are not worn. that was the second thing i had to do. belt was spinning but not the pulley.

when the dash light glow  , is a bad regulator .  You will get   ac  readings  on your  volt  ohm meter .I have had  " rebuilt alternators "  bad out of the box .  some rebuilders  just    clean and replace  only the bad parts  .  and they don't properly test  the regulator  . 

All the warning light are on. Like when you turn the key to the on position except they all stay on when you start the car.

that is not uncommon when the alternator has no output.

Just ran a ground wire from the alternator to the battery negative terminal. Didn't fix anything but when watching the alternator and belts spin, they didn't spin consistently. They would spin then slow down for a tiny bit then keep spinning.

  Just a note:  Loyale alternators are notorious for going out.  It seems to be the high range (speed) diode.  As I have heard, they are not user-friendly to repair.  I pulled lots of used alternators off in the wrecking yard and had them tested at an auto supply store.  They all tested good until you used them for a while. 

  Oriley's sells LIFETIME replacement generators.  I did that and never had a problem since.

 

Bruce in Spokane

Just ran a ground wire from the alternator to the battery negative terminal. Didn't fix anything but when watching the alternator and belts spin, they didn't spin consistently. They would spin then slow down for a tiny bit then keep spinning.

This sounds odd..  The belts are driven by the crankshaft.  How can the speed be varying?  Are they slipping?  Slipping is usually accompanied by squealing.  The voltage measurement to verify charging should be done with no accessories turned on, engine idling, and also, raise the RPM to 1000-1500 or so, if the voltage is below 13.8. [it also should not go crazy high, like much over 14V]   At the extreme slow side of idle, the alternator doesn't put out a lot of power.

 

I don't know about after market alternators, I have always rebuilt my own.

If the warning lights come on, you have a bridge rectifier diode failure. Which is a component of the voltage regulator, built into the alternator, and neither available nor easily serviceable. To fix that you replace the alternator. Period. There is no other failure that can create the Christmas tree effect.

 

If you get an alternator for an 85 to 94 Nissan Maxima it will bolt in. Just swap the pulley and the harness connector, etc. These are 90 Amp units. Order a Denso or Mitsubishi remanufactured unit. It won't be cheap but you get what you pay for.

 

Make sure you battery is FULLY charged, and all your wiring is good.

 

GD

Edited March 8, 20179 yr by GeneralDisorder

aspwholesale.com has every part for the OEM Hitachi alternators.  And lots more.

 

I bought bearings, brushes, slip rings, rectifiers, regulators, insulators. 

 

I do have electronics background, so these things are no big deal to me to repair, I know most just buy re manufactured ones.

It's more the labor to do it than it is anything else. Denso and Mitsubishi both do reman units for a fair price. At least in a shop environment it's more cost effective to replace - it also requires less skilled labor. Sad but that's the reality of our times.

 

GD

If the warning lights come on, you have a bridge rectifier diode failure. Which is a component of the voltage regulator, built into the alternator, and neither available nor easily serviceable. To fix that you replace the alternator. Period. There is no other failure that can create the Christmas tree effect.

If you get an alternator for an 85 to 94 Nissan Maxima it will bolt in. Just swap the pulley and the harness connector, etc. These are 90 Amp units. Order a Denso or Mitsubishi remanufactured unit. It won't be cheap but you get what you pay for.

Make sure you battery is FULLY charged, and all your wiring is good.

GD

Agree with this on the swap. Seems like they work much better and swapping the pulleys is pretty easy. There is a lot of info on here about how to do it. Just don't grab one from auto zone unless you really have to. I got mine from there and the first two I bolted on were crap out of the box. Lucky for me third times the charm and this one has been going strong for a while. Good luck and let us know what happens.