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machine gun preacher
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Discussion Starter · #1 ·
this morning, went out to the truck and she won't turn over. :banghead

usually fires right up.

Battery is 2 months old.

Alternator idiot light is on, but according to the volt meter it charges at just under 14V while running.

On Sunday, I installed a headlight harness from fireguy. Wouldn't really think that would be my drain though.

any ideas? guesses? hopes?

thanks.
 

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machine gun preacher
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Discussion Starter · #3 ·
I did not, as the only "electrical" connection was to the positive post. No connections were broken. I will pick up a new positive cable this afternoon and give it a jump from my car...although, I drove it two days with multiple starts with no issues.
 

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make sure she is fully charged (if not, you may have a short draining the system or had the lights on), and check the voltage at the battery before and while turning her over. voltage should stay above 9v during the start cycle. if that is good, do so across the solenoid. finally, check at the starter. it is not uncommon to have a battery go bad, even off the shelf. it happened to me for the one i just bought for my '79, and it drove me absoultely crazy.

edit: a bad starter solenoid often results in intermittent starting. i'm more of a chevy guy, so i'm not used to the ford starting setup well enough to help more than that. if it starts sometimes, but not others, your starter may be bad. best to check the voltages first though, as it may test good on the bench if you pull it.
 

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I'd tend to trust a volt meter over a 30 year old alt light, although the voltage does seem a little low. But I admittedly missed the part about the idiot light when I wrote my first post. Regardless, I guess first question we should answer is: Was the battery discharged when it wouldn't start?
 

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machine gun preacher
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Discussion Starter · #11 ·
arrgh.... I'm taking the alternator in tomorrow to be tested. However, the truck had 12V at the battery and started with a jump. At the battery, I was getting 13-13.5V.

I drove it around for about 20mins, came home, shut it down. Tried to start it again and nothing.

Also, now I'm getting voltage spikes. from 14-16V.

what in the world did I do???
 

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I'd put money on bad diodes. Have that alt tested and let us know what you find out from there. You can have bad diodes and still show a fully charging system. Bad diodes will drain a battery in no time.
 

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machine gun preacher
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Discussion Starter · #14 ·
took the alt in....it was bad. got a new one. Put it in, decided to get a new starter solenoid while I was in there.

Jumped it off of my car, fired up after a min or two. went around to the front of the truck, took the neg jumper cable off and the truck dies....

now, it won't even jump start.

I'm quite quite confused.

Also, how many leads are supposed to be on the alternator, in the back? I have two. Should there be more? I found what looked to be another "push" on, type of lead as I was dealing with things.

Thanks for the help.
 

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took the alt in....it was bad. got a new one. Put it in, decided to get a new starter solenoid while I was in there.

Jumped it off of my car, fired up after a min or two. went around to the front of the truck, took the neg jumper cable off and the truck dies....

now, it won't even jump start.

I'm quite quite confused.

Also, how many leads are supposed to be on the alternator, in the back? I have two. Should there be more? I found what looked to be another "push" on, type of lead as I was dealing with things.

Thanks for the help.
First....you screwed up. You failed to label or take note of what wires went where. Next time be more thorough.

Second, there are three wires that go to the back of the 1G alternator. The large wire goes to the large B+ terminal, the white / black stripe wire goes to the S (stator), and the black wire goes to the F (field). The field wire could be green, black, orange, etc....I have seen them other colors.

http://www.fordfuelinjection.com/public/alternator/1G-ALT_wiring.gif

Finally, get that battery charged before you hook it up to a new alternator. Parts store alternators are junk, and hooking one up to a dead battery could kill it.
 

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machine gun preacher
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Discussion Starter · #16 ·
First....you screwed up. You failed to label or take note of what wires went where. Next time be more thorough.

Second, there are three wires that go to the back of the 1G alternator. The large wire goes to the large B+ terminal, the white / black stripe wire goes to the S (stator), and the black wire goes to the F (field). The field wire could be green, black, orange, etc....I have seen them other colors.

http://www.fordfuelinjection.com/public/alternator/1G-ALT_wiring.gif

Finally, get that battery charged before you hook it up to a new alternator. Parts store alternators are junk, and hooking one up to a dead battery could kill it.
thanks for the help??

The truck came to me as is. It was a basketcase. 90% of what I've done to the vehicle so far has be attempting to fix the previous owners mistakes. So, no, I didn't screw up, it was like that.

what is the B+ terminal?

thank you for the wiring advice though. Now I know where things are supposed to be. The battery is being charged as we speak.
 

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The B+ (or 'BAT' in some cases) terminal is the alternator output - it should be labeled on the back of the alt. It is the one with the red ring around it in the picture below. It goes to the battery side of the starter solenoid to charge the battery - at least, that's the easiest and most hassle-free way of doing it. Everything you need to know to hook up the alternator is on that schematic bigwheelz posted. Don't mind the wire colors, just trace the wires from the regulator (located on the passenger side fender) to the alt.

 

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thanks for the help??

The truck came to me as is. It was a basketcase. 90% of what I've done to the vehicle so far has be attempting to fix the previous owners mistakes. So, no, I didn't screw up, it was like that.
I don't doubt that is true....a 30 year old truck usually will have more than its fair share of shoddy repairs.

However, bear this in mind: Your alternator would never have worked in the first place if it was not hooked up correctly. Not trying to be mean, just stating a fact.

There is a possibility that the 30 year old push on fitting just "fell" off the back of your alternator. I have had it happen to me....If the fittings are loose I suggest you solder on some ring terminals and bolt the wires on. :beer
 
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