Starting issues, alternator, & battery draw

[Legacy777]

I've been having starting issues over the past year or so. The car wouldn't start. Sometimes if I wait, it'd start, or just try again. Other times I'd need a jump, and it would always start then. Most of the time I would hear a click, like the starter solenoid was engaging, but maybe not having enough juice to fully engage.

When I did my AT & MT swap, the starter contacts were replaced, and everything seemed ok. I did some testing this past weekend. I removed my starter interlock relay circuit from the starting circuit, and the car tried to turn over, but the battery was low. So I'm not sure if it was luck that it started, or that my starter interlock circuit is messed up.

Also, when I swapped in my HO alternator, I had used the connector that came with it, which is like the newer subarus, but it wasn't water tight. I got a connector from Matt that was water tight, thanks Matt. I finally put that in this past weekend as well.

When I checked my battery, the voltage was around 11.8v or something like that. I charged the battery up, and the car did start. I monitored the voltage from the select monitor after initially starting up, and the battery voltage was still around 11.8v. Finally after a minute or so, the lights brightened up, and the voltage jumped up to 13.8v with a high idle. After the car was warmed up, the voltage was 12.9v.

So I'm not sure if my alternator was messed up, or not producing enough voltage to charge the battery. Is 13.8v about normal? Also, is the alternator responsible for voltage regulation, or does the ECU have any say in voltage regulation?

Other thing I checked was to see if I have excess battery draw when the car is off. I ended up with 28.9 milli amps. The amps slowly rose to that, and more or less stabilized around that. Is that an excess amperage draw? Has anyone else checked their amperage draw when the car is sitting and everything is off?

Here's a thread with a little more info
http://bbs.legacycentral.org/viewtopic.php?t=33021

Any thoughts/comments?

[vrg3]

When I checked my battery, the voltage was around 11.8v or something like that.

That's a low voltage. 11.8 volts with no load means the battery was probably something like two-thirds discharged.

I monitored the voltage from the select monitor after initially starting up, and the battery voltage was still around 11.8v.

Hm. Sounds like the alternator's field coils weren't energized.

Finally after a minute or so, the lights brightened up, and the voltage jumped up to 13.8v with a high idle.

So the field coils finally got excited. 13.8 volts is usually about what you like to see.

After the car was warmed up, the voltage was 12.9v.

12.9 volts is a little low, but most high-output alternators actually work poorly at low speed; I believe we had a discussion about that when you first looked at this alternator.

After the car was warmed up, did the voltage go back to about 13.8 volts if you revved the engine?

Also, is the alternator responsible for voltage regulation, or does the ECU have any say in voltage regulation?

The ECU has absolutely nothing to do with it. The voltage regulator is bult into the alternator (it's what you plug the harness connector into). In the stock setup, it has three wires -- one connected to the ignition switch to power the regulator (and thereby the field coils), one connected to the fuse box to provide the regulator with feedback so it knows how much voltage it's producing, and one connected to the idiot light on the dash so it can report when it thinks it's malfunctioning.

If I recall correctly, your alternator only has that last wire. It's self-exciting, which means the regulator powers itself off the turning of the alternator. It only starts exciting the field coils after you reach a certain RPM, though, which you only reach the first time you start driving the car. You may need to rev it higher than you normally do.

When you did your test, was the engine just idling, or were you driving?

Is it possible that everything is working correctly but your driving style coupled with the way this alternator works is leaving you with a discharged battery? Maybe you need to give the engine a quick rev to 3000 RPM or something every time you drive?

You're not using an underdrive pulley, are you?

Other thing I checked was to see if I have excess battery draw when the car is off. I ended up with 28.9 milli amps.

That's fine. 40 mA is the cutoff point; if it's above that you can start to worry.

[Legacy777]

12.9 volts is a little low, but most high-output alternators actually work poorly at low speed; I believe we had a discussion about that when you first looked at this alternator.

After the car was warmed up, did the voltage go back to about 13.8 volts if you revved the engine?

Yeah I remember the discussion about the HO alternator, so yeah that didn't surprise me about the 12.9 volts. Yes when I revved the engine, the voltage went back up to 13.8 volts.

The ECU has absolutely nothing to do with it. The voltage regulator is bult into the alternator (it's what you plug the harness connector into). In the stock setup, it has three wires -- one connected to the ignition switch to power the regulator (and thereby the field coils), one connected to the fuse box to provide the regulator with feedback so it knows how much voltage it's producing, and one connected to the idiot light on the dash so it can report when it thinks it's malfunctioning.

If I recall correctly, your alternator only has that last wire. It's self-exciting, which means the regulator powers itself off the turning of the alternator. It only starts exciting the field coils after you reach a certain RPM, though, which you only reach the first time you start driving the car. You may need to rev it higher than you normally do.

When you did your test, was the engine just idling, or were you driving?

My alternator, just like the newer subarus have 2-wires, the last two wires. It has an rpm turn on. I could actually look at using a newer alternator off a new legacy or something like that. It has an amperage output that is close to the one I'm running I think, and may be better suited to daily driving. The wiring changes I made should allow it to just drop in.

The engine was idling first, but I did drive it around also.

Is it possible that everything is working correctly but your driving style coupled with the way this alternator works is leaving you with a discharged battery? Maybe you need to give the engine a quick rev to 3000 RPM or something every time you drive?

It's possible. I also think it may be because I don't drive the car as much. However I have had issues where I put the battery on the charger over night, started the car, drove it, and then tried to restart it and had issues. I knew the battery should have been charged since I was driving......unless for some reason the old plug I just replaced was causing me some greif.

A couple weeks ago, I drove the car every day for a week or so, and I didn't seem to have any problems that I can recall, so it may be a combination of things.

You're not using an underdrive pulley, are you?

No, Not sure if you remember, but I even did the calcs to check the turn on speed with the stock diameter pullies, and decided to get a smaller alternator pulley from GFB to overdrive the alternator so the turn on speed would be closer to my engine idle speed.

That's fine. 40 mA is the cutoff point; if it's above that you can start to worry.

Ok.....It was lower, and started going up, and plateaued around 28.9mA. I don't know if the capacitor in my stereo system might have been giving me some weird readings.

[jefferson]

If you ended up with a smaller diameter crank pulley then you have an underdrive pulley that is spinning your alternator slower. A larger than stock size will spin the alt. faster. It's just like the gearing on a motorcycle, but you substitute the crank pulley for the countershaft sprocket.

Jeff

[vrg3]

Josh - Switching to an OEM alternator would actually be a good way to ensure reliability, I'd say. It does kind of seem possible that your alternator's not always self-exciting properly.

Maybe hook up a voltmeter (you can just drop like $20 at AutoZone for a cheap voltage gauge and a cigarette lighter plug) and watch the voltage carefully to monitor its behavior.

I don't see how the presence of a capacitor would affect the results of these tests.

Jeff - He didn't put on a smaller crank pulley; he put on a smaller alternator pulley.

[jefferson]

Sorry, I missed that somehow.

Jeff

[Legacy777]

I drove the car on Thursday of last week before I went out of town for the holidays, and had some intermittant issues with the brake, charge lamps coming on. So either the alternator is having issues, or the wiring modification I did is not right.

What I'm leaning towards is picking up a cheap used newer impreza alternator and plopping it in to see if I still get the warning lights coming on. If so, then I probably have issues with my wiring. Otherwise, the alternator is probably not working properly.

After all the issues, I'm very tempted just to get a brand new newer subaru alternator if it does turn out to be an alternator issue.

[Adam West]

Cheap alternator herein the Northwest. Don't know seller...

http://forums.nasioc.com/forums/showthr ... ?t=1418234

[Legacy777]

I think I found one on the USMB. Thanks though.

[Legacy777]

Well I swapped in the used alternator I got yesterday evening.

The HO alternator appeared to not be working when I started up the car yesterday to move it into the garage. Battery voltage was like 11.28 with the engine running, and revving the engine didn't change voltage, but the car did start.

When I put in the other alternator, the voltage was 14.3 or something like that with a fast idle. It settled out to around 14.1 with normal idle. The car seems to idle better. I really haven't noticed any difference in how it drives/runs, but will be driving it probably for the next week.

I'm planning to send the HO alternator in to get it looked at to see if it can be repaired or not.

[evolutionmovement]

!4.4 is high end perfect, so that's a damn good one. Good luck getting the other one rebuilt. You ordered it custom, though, right? I know the damn OEM ones cost almost 3x more to rebuild than buying a new one.

[Legacy777]

A guy in Dallas was selling the HO alternators. He emailed out of the blue the other day, which was a coincidence because I was going to email him about my issues.

He has since changed suppliers, so I'm going to see what they can do. To my knowledge they build alternators to spec or what not. I'll find out more when I talk to the supplier.

[vrg3]

I wonder if it's just the diodes or the regulator that have gone bad because they weren't designed for this much current.

[Legacy777]

Yeah....Chad emailed me back...he talked with his supplier....they said it's probably the regulator....or possibly the rectifier.

I'm going to call later today and will be sending it up there to be looked at.

[evolutionmovement]

Either one means a rebuild anyway as they're all internal. When I replaced mine after 1/4 million it was just one of the diode packs that was intermittently failing (there are 3, obviously) and the charge was going in and out. IIRC, the packs came together for almost $300 and I couldn't find any other source but the damned dealer and even that was tough. Nobody likes to fix things anymore. Damn willfully-ignorant wasteful consumer culture.

[Legacy777]

I have an update. Things have been hectic around home.

They found the regulator to be bad, or working intermittantly. They replaced the regulator and shipped it back to me.

I measured the voltage, and I'm getting around 13.6-13.8.....and revving the engine doesn't seem to do anything to change the voltage. The old alternator seemed to give a higher voltage.

They gave me some things to test, and check voltage drops. I haven't had time to do that, but will when I get time.

One other note on my starting issues. I believe some of my issues with not starting is due to the harness I setup to include the starter interlock relay. When the car sits for a while, and I try to start it, it won't start. If I remove the connector going to the ignition, and plug it back in, it'll usually start, or at least turn over. So I'm not sure if my issue is in the wiring, or possibly a worn starter interlock relay.

Thoughts?