Bat Light + Alt questions / problems

[joesho_gb]

Fixed one problem, got another.

This has been a gremlin for the past 2 months or so. Finally it crippled me this evening. It started after I replaced my valve cover gaskets.
The battery light would come on every so often. The light wasn't bright bright, but was there. Sometimes revving the motor made it go away, sometimes not.
What always fixed it was a good shake or nudge of the 12+ cable on the battery terminal. I knew I had it when the car would rev up. After that, was fine.

Tonight, started it, batt light on. Shook the cable, still the same. So I started checking things. Reseated the positive and negative cables in the post holders, tightened everything up. Still the same.

On the alternator side of things. there are 3 wires in the harness.
Yellow Wire - +15 volts
Black Wire - 0
Green / Red - approx 5 volts

When I changed to the continuity testing, the black wire didn't do anything.
I don't know the colors, but I assume the black is ground. Is there a fuse-able link in there somewhere that I don't know of?

The battery is about a year and a half old, alternator was rebuilt a year ago. I cleaned all the grounding connectors on the intake, reseated the other end of the intake ground wire to the chassis (when I last had the intake off, about 2 months ago)

Any ideas?

 

[Phoenix]

A batt light is 99% the time - your alt is toast.

 

[Ashley_MTX]

+1 but have you started checking sensors?

 

[medgraphsho]

these are the same symptoms I had on my 92.... battery light came on faded at idle and as you would accelrate it would go out... trust me, change your alternator now or you may end up replacing the battery also

 

[joesho_gb]

is it possible to change just the voltage regulator?

 

[Ashley_MTX]

Either way, I just had to change my alt. about a month ago and was fortunate enough that the battery light kept coming on rather than it just dying on me. The only other thing is if you do a search there's one guy who did say he kept having alt./battery problems and it ultimately ended up that he had a bad starter. Apparently because of how the charge goes, the starter was actually sapping the alternator and battery.

 

[SHOZ123]

The voltage regulator is changeable. On the newer alternators it is part of the brush pack.

 

[sho'noffmtx]

If you take it to any auto parts store they should be able to test it for free for you in hopes that if it is bad they will earn your business.

I have a 3yr warrenty on my reman alt so maybe you have something similar where they will just give you a whole new one. Good luck

 

[joesho_gb]

Ok, dumb ? here, but I don't want to tear apart a bunch of stuff that I don't need too, bot to get the alt out, I assume I need to take out the battery, the coolant reservoir and washer fluid reservoir to get the belt off, then pull the alt?

Am I correct or way off?

 

[Green Sho]

I remove my coolant reservoir, the battery and the battery tray so I can get to the tensioner for the belt. I have a 5spd though I'm not sure if yours is automatic or not..

 

[joesho_gb]

yea, ATX. I assume that part is pretty similar (the bolts and belt). I know that the belt is different, and a MTX alt and an ATX alt don't work, but I can't imagine that getting the belt loose should be that different.
Guess I'll just start pulling stuff and see what happens.
Figure I still have my Beretta running, so at least I have a ride.

 

[Ashley_MTX]

Ok, dumb ? here, but I don't want to tear apart a bunch of stuff that I don't need too, bot to get the alt out, I assume I need to take out the battery, the coolant reservoir and washer fluid reservoir to get the belt off, then pull the alt?

Am I correct or way off?

Again, the search function is your friend here. Just search alternator or battery light or changing alternator and all three of those should take you to multiple threads on this. One of the things that I saw was a BUNCH of stuff on changing the alternator in an ATX.

 

[jmpSHO]

You don't really need to remove anything except the battery to remove the alternator and one of the pulleys so you can get one of the alternator bolts out. To remove the belt I move the PS reservoir out of the way and use a regular rachtet with a breaker bar for added leverage. I have also removed the belt going from under the car when I have it on a lift.

 

[FOMOCOTOSHO]

If you take it to any auto parts store they should be able to test it for free for you in hopes that if it is bad they will earn your business.

I have a 3yr warrenty on my reman alt so maybe you have something similar where they will just give you a whole new one. Good luck

Never trust a bench test for an alternator, it is deceiving because they do not test the alternator with a load. To get a proper test take it to a shop so it can be tested on the vehicle running.

 

[SHOZ123]

All you need is a voltmeter and the car running to see if the alternator is good. First on a warm motor with the engine off check the battery voltage. Should read 12.3 or so. Anything under 12V it is undercharged. Attach the meter and crank the engine. If it drops below 11.3V the battery is again either undercharged or bad. You cannot determine the state of the battery if it has not been charged up for at least 4 hours (if it was dead) or driven for at least 15 minutes.

Then start the car, turn on all the electrical devices you can, AC to get the fans going, heater fan on high, rear defroster and headlights. Then check the battery voltage with the engine running around 1500 rpms. It should be above 13.5V. If it isn't then the alternator is on the way out.

 

[Ashley_MTX]

Never trust a bench test for an alternator, it is deceiving because they do not test the alternator with a load. To get a proper test take it to a shop so it can be tested on the vehicle running.

Depends on where you take it. When I took mine they tested it at idle and then had me hop in the the car and press the gas for a minute (or...a few seconds). Maybe not quite like it would've been going down the street but the alternator tested bad both times and that's what it ended up being. Or at least...the battery light went off after I changed it....

 

[badcamelot]

First - bench testing at the local parts store is a WASTE of time. I had two different batteries and two different alt's. All 'tested' fine. they werent.
I also had my starter draining everything. But your symptoms dont sound like the starter is causing the problem.

Second - removing the alt from an ATX is easy (now I've done it numerous times) and the battery does not need to be removed. I believe it's a 15mm socket with long bar to release tension on the serp belt. Once you have the belt off, remove the tensioner that is in front of the alt. This bolt and all the bolts (4) holding the alt in place are 13mm. There is the 10mm holding the wire on the back of the alt, just loosen this before alt removal, I leeave it attached though, cause I kept dropping the blasted 10mm nut! You will not be able to get at the bottom front bolt on the alt without removing the tnesioner.

third - alternators are poorly designed or built for these engines. I found a link to buy them free of shipping for $135 ish. I have found a couple in junkyards and therefore have just used those until I get that friendly little glow....then replace the alt.

Good luck

 

[Ashley_MTX]

First - bench testing at the local parts store is a WASTE of time. I had two different batteries and two different alt's. All 'tested' fine. they werent.
I also had my starter draining everything. But your symptoms dont sound like the starter is causing the problem.


third - alternators are poorly designed or built for these engines. I found a link to buy them free of shipping for $135 ish. I have found a couple in junkyards and therefore have just used those until I get that friendly little glow....then replace the alt.

Good luck

It may be a waste of time to some but sometimes it can be helpful in ruling things out. It was helpful to me to confirm that it was a bad alternator (versus battery or starter) in my car. It's just a good idea if you're having those symptoms and the alt/battery test 'good' to keep in mind the test may not be completely accurate.

I got my alternator for $130 from the local store. The price is about the same and you'll probably have to wait a day or more either way.

 

[joesho_gb]

Thanks for all the great feedback and support. Got busy with work this week, so I haven't had a chance to pull it yet.
That's the plan for tomorrow.
As for the voltage, I have hooked up a charger to the battery, til it got a good 13+ volt charge. Before I start, no voltage drop. Starting drops it down to about 12.75, after letting it warm up for a few minutes, the voltage drops to about 12.25ish.
Setting the volt meter so I can see it from the drivers side, move the throttle cable on the throttle body to rev the motor. All the volt meter does it drop.
I did some checking (found some old receipts in the glove box), and the alternator wasn't replaced in Sept. 08, just rebuilt. Called the place that rebuilt it, and the voltage regulator wasn't replaced, just some copper bushings and stuff (if memory serves).
I'm going to just pull it and bring it to a place that rebuilds them here locally. It'll take a few days, but at least it will work.
I miss my SHO, driving the Beretta just isn't the same.

 

[geomarathoner]

Sure sounds like a puny alternator, all right.....and FWIW, you can get a completely remanufactured one at Advance Auto...always in stock...no waiting.