Alternator problem? (1 Viewer)

[koszowskima]

Hey all, I took my 87 fj60 for a drive yesterday. No problems starting, it was a 30 min drive, I parked and then went to grab food and came back (gone for about 20 min). I replaced the battery about two weeks ago so no problems there (the car was super dead one morning and a jump/trickle charge did nothing). When I got back to the car I tried to start it up, the car sounded like it was about to start but never did. The battery (charge icon) lit up when I was trying to start it. A guy gave me a jump (which kind of worked, I still had to try and start like 3 times). The guy who gave me a jump said it looks like I have a bad alternator. I have never had a problem with dimming lights or other signs of a bad alternator.

IMPORTANT side note: I am a young guy and new to old cars. Giving it a little gas when starting it up was a foreign concept to me. After a debrief with my dad this was cleared up. After I got it home the next morning it started no problem with a little gas.

Thanks

 

[OSS]

If the starter cranks over fine then the hard start wasn't battery related. When the engine is hot, it can sometimes need to be started differently.
When hot: press gas pedal down about 3/4 of the way or so and don't pump the gas pedal. Just hold it there.
With clutch pedal pressed all the way down and choke knob not pulled - turn the ignition key on.

Try that next time its hot

 

[AlpineCruisers]

If you start to experience regular problems with this, I would keep the voltage regulator in mind. I had a 60 once that I had constant issues with thinking it was the alternator or a ground wire, etc. Every time I had the alternator tested, it was fine. After months of frustration, it ended up being the VR (which can sometimes be due to a cheap or incorrect replacement of the alternator.)

 

[cruiserpilot]

You could easily pull the alternator and take it to an auto shop and have it
’Load Tested’. Generally alternators seem to work fine until you load them up.
This is very inexpensive, and in some cases they will test for no charge.

 

[koszowskima]

Hey all,

Update on electrical problems:

After the adventure above, I started it a few days later with no problem. I didn't touch it for about 3-4 days, occasionally grabbing something on the inside (lights turned on etc). I figured it was all good. This morning I tried to start it and the engine barely turned over. I jumped it and go it going again. It drives perfectly and starts with no problems after a drive too. Something seems to be slowly killing the battery. I am trickle charging the battery now. My hope is when it died and I did not drive it around long enough to fully charge the battery so it has been sitting in limbo.

Any thoughts on what might be draining the battery? It's not like the car has a lot of buttons that could be turned on.

 

[OSS]

A dead battery needs about 6 hours on a charger to get fully recharged - depending on the charger. If a dead battery is jump started and driven for less than 2 hours, it's not even half way charged. 30 minutes is like almost no charge.

The general method used in trying to find a parasitic drain in the vehicle is to remove 1/2 of the fuses in the fuse panel after the battery has been fully charged on an AC charger - then let it set over night and see what happened.
If the battery charge is fine the next morning, the next time, remove the same fuses except a few - and see what happens the next morning again.

Through the process of trial by elimination it's possible to find the offending circuit without having to pull every fuse to find the culprit.

There's an accessory somewhere that's leaking current. It's protected through one of the fuses

 

[g-man]

Think of your battery as a reserve pool of energy for starting and the alternator as something that generates a smaller amount and runs all your electronics going down the road and as well as charging the battery. If your alternator completely fails going down the road your voltage reading will be whatever is in the battery and then your electronics ...all of them including coil will draw from you battery until it's drained.

When you're driving keep an eye on the voltage gauge. They are not very accurate but generally should show around 13 to 13.5 if your vehicle's alternator is charging. Below 12 v and something is wrong...and your battery is not getting enough charge and the alt and/or the VR is bad. The IGN light comes on when things get low...kinda a dummy gauge.


Get a decent multi-tester and check your battery with the truck off. A new battery should read about 12.5 to 13.1 volts. Then check the battery while the truck is running, the voltage feeding from the alternator should be what you are now reading. About 14 to 14.7 volts idling at 2000 rpms for a stock fj60

Ensure your battery terminals and fusible links are not loose, corroded or burned.

You can test for a parasitic draw by putting a 12v low voltage tester in between the positive post on the battery and the positive battery cable terminal. In other words take the positive cable off and clamp the tester probe to the metal on the cable terminal, and clamp the other end to the battery positive. With the truck off and nothing running You should see no light on the tester ...unless you have a draw. If you do, you should pull fuses, one at a time until the light goes out to find out which circuit is drawing. Obviously you will have to make sure the door light switch is off and just make sure everything is off.

 

[Seth S]

Think of your battery as a reserve pool of energy for starting and the alternator as something that generates a smaller amount and runs all your electronics going down the road and as well as charging the battery. If your alternator completely fails going down the road your voltage reading will be whatever is in the battery and then your electronics ...all of them including coil will draw from you battery until it's drained.

When you're driving keep an eye on the voltage gauge. They are not very accurate but generally should show around 13 to 13.5 if your vehicle's alternator is charging. Below 12 v and something is wrong...and your battery is not getting enough charge and the alt and/or the VR is bad. The IGN light comes on when things get low...kinda a dummy gauge.


Get a decent multi-tester and check your battery with the truck off. A new battery should read about 12.5 to 13.1 volts. Then check the battery while the truck is running, the voltage feeding from the alternator should be what you are now reading. About 14 to 14.7 volts idling at 2000 rpms for a stock fj60

Ensure your battery terminals and fusible links are not loose, corroded or burned.

You can test for a parasitic draw by putting a 12v low voltage tester in between the positive post on the battery and the positive battery cable terminal. In other words take the positive cable off and clamp the tester probe to the metal on the cable terminal, and clamp the other end to the battery positive. With the truck off and nothing running You should see no light on the tester ...unless you have a draw. If you do, you should pull fuses, one at a time until the light goes out to find out which circuit is drawing. Obviously you will have to make sure the door light switch is off and just make sure everything is off.

technically the battery is what the truck runs off of and the alternator just replaces the charge that gets used. It just happens that the alternator creates a small surplus of amperage/voltage and that varies based on the electrical load (demand) so that the battery stays charged. An FJ60 will drive a couple hundred miles during the daytime with a fresh battery and a dead alternator. An FJ62 will be less given the efi and the fuel pump etc. a 1999 Saab 900 will go about 47 miles if the alternator fails on a cold winter night in Vermont in January.

 

[mccracken]

I had a alternator die in August but before I zeroed in on the root cause I went through every step g-man just laid out. I'd be curious to to know if this doesn't get you where you need to go! Electrical "gremlins" always seem like witchcraft until you find the problem and then everything works again.

Think of your battery as a reserve pool of energy for starting and the alternator as something that generates a smaller amount and runs all your electronics going down the road and as well as charging the battery. If your alternator completely fails going down the road your voltage reading will be whatever is in the battery and then your electronics ...all of them including coil will draw from you battery until it's drained.

When you're driving keep an eye on the voltage gauge. They are not very accurate but generally should show around 13 to 13.5 if your vehicle's alternator is charging. Below 12 v and something is wrong...and your battery is not getting enough charge and the alt and/or the VR is bad. The IGN light comes on when things get low...kinda a dummy gauge.


Get a decent multi-tester and check your battery with the truck off. A new battery should read about 12.5 to 13.1 volts. Then check the battery while the truck is running, the voltage feeding from the alternator should be what you are now reading. About 14 to 14.7 volts idling at 2000 rpms for a stock fj60

Ensure your battery terminals and fusible links are not loose, corroded or burned.

You can test for a parasitic draw by putting a 12v low voltage tester in between the positive post on the battery and the positive battery cable terminal. In other words take the positive cable off and clamp the tester probe to the metal on the cable terminal, and clamp the other end to the battery positive. With the truck off and nothing running You should see no light on the tester ...unless you have a draw. If you do, you should pull fuses, one at a time until the light goes out to find out which circuit is drawing. Obviously you will have to make sure the door light switch is off and just make sure everything is off.

 

[koszowskima]

Thanks all,

It was charging all night. I am going to drive it around a bit today, and later this weekend I am going to check those fuses. The main fuse box... is that by left knee?

 

[Seth S]

Thanks all,

It was charging all night. I am going to drive it around a bit today, and later this weekend I am going to check those fuses. The main fuse box... is that by left knee?

Yes left knee. Also check that your battery terminals are clean and tight, check your battery cables are in good condition. And make sure your fusible link at the battery is clean and the wires and connectors are in good shape.

 

[koszowskima]

UPDATE:
I let it trickle charge and I started three times over the course of about 1.5 weeks. No problems. I started it two days ago and it was fine, and today I tried it, and completely dead. Not a single light turned on, no dorr dinging. The key turned with no reaction from the car.

The battery was fully charged two weeks ago, started it multiple times with no problem, started the other day (it has been cold outside), and then nothing today. I tried jumping it but it seemed like the battery wasn't taking charge. Last night I charged it overnight and then this morning totally dead. It seemed the battery wasn't taking or holding any kind of charge.

Help

 

[morganism]

I hate to say this, cuz everyone else knows whats coming...

Pull the coil hold down cage, and clean the contacts between the coil body, igniter (if u have one in that model), and body.

it is one of the main grounds. Should make your headlights brighter too....

 

[Seth S]

Have you verified the alternator is charging yet? 13-14.4 bolts when it’s running and bat light on dash off?

 

[koszowskima]

Hey all,

Thank you so much for the suggestions. After ripping out a horribly installed 3rd party alarm system (which was not the problem, but could have caused problems) the culprit was a poorly grounded negative terminal on the battery. I tightened the bolts so they touched and tightened where the wire grounded to the chassis and BOOM the thing lit up.

I got some great experience with the electrical system and the thing is running great!

Thanks

 

[GeologistFelix]

technically the battery is what the truck runs off of and the alternator just replaces the charge that gets used. It just happens that the alternator creates a small surplus of amperage/voltage and that varies based on the electrical load (demand) so that the battery stays charged. An FJ60 will drive a couple hundred miles during the daytime with a fresh battery and a dead alternator. An FJ62 will be less given the efi and the fuel pump etc. a 1999 Saab 900 will go about 47 miles if the alternator fails on a cold winter night in Vermont in January.

A 1990 Jeep Cherokee will drive you 2 miles to work and back during daylight about 10 times before the lights get weirdly dim, the turn signals get sloooooow, and you realize you forgot to plug the alt back in when you were monkeying around under the hood the last time. It sounds like you had more of an adventure than I did learning about alternators...