I need help with some intermittent charging

[RustedJunk84]

Im sorry if I cant get back to answer questions much but I will try my best to answer what I can when I can.

So I have the 86 302EFI and for some reason I am having a intermittent charging problem. It seams if

I drive during the day the alternator puts out enough power to charge. Acts like alternator is putting out required voltage (13.8-14.3). When I drive at night with a load such as headlights, heat, or wipers on it has a tendency to stop charging. It will kick in and out intermittently while driving. Sometimes you can drive a good distance before it will stop charging. When it does stop charging then it may kick back in but it may also take a while before it starts charging again. I have driven with just headlights on and the alternator still acted up. Today I drove with the headlights OFF and the wipers on intermittent and it stopped charging again. So as I drove through the rain today and I would turn the wipers on only when i couldn't see anymore. Seamed to stay charging. I fell as if i have a high resistance somewhere or that the amperage is to low. The alternator is the 2G with the regulator mounted on the alternator.

I am not running anything big in the truck such as a sound system or off road lights. My phone charger is the only thing not factory. I have even had the cigerette/charger port discounnected and it still intermittently charged.

 

I have: 1986 F150 302EFI 2wd auto

 

Replaced alternator 3 times

Had the battery tested good

Checked all the battery grounds

Replaced a new start solenoid because I had a new one sitting around.

Replaced/soldered new plugs for the alternator and checked the wires.

Traced the wires across the motor all looked good and replaced random wires that may have been messed up.

Tried a different computer for fun since i had one sitting around.

Traced wires back into the cab across the dash and under dash found no shorted wires.

Pulled the fuse panel off the fire wall and checked connections.

Checked all the fuses

Replaced the alternator belt with a new one.

 

Any help would be grateful I have been working on this for a month and a half now.Thank God I work close to home and live in town.

Instagram: RustedJunk84

[Gary Lewis]

An '86 should have the 2G alternator, which was phased in that year. But you can ID your alternator using the pics here: Electrical/3G Alternator Conversion.

And it is important to determine what you have because if you have the 1G you haven't mentioned the regulator, which is external to the 1G. But the 2G has an internal regulator.

There's a TSB here about the 2G, but I'm not sure it is much help. However, the 2G's have a problem with the connectors becoming loose and causing problems - even fires.

I'm not saying that you need to change to a 3G, but if it was me I'd seriously consider it. I think you either have connector or alternator problems, and I think it is probably the connectors. They lose their tension, which causes heat, which reduces tension, which causes heat, ....

But, you said you replaced and soldered the plugs to the alternator. Maybe you've already addressed this issue?

 

[RustedJunk84]

An '86 should have the 2G alternator, which was phased in that year. But you can ID your alternator using the pics here: Electrical/3G Alternator Conversion.

And it is important to determine what you have because if you have the 1G you haven't mentioned the regulator, which is external to the 1G. But the 2G has an internal regulator.

There's a TSB here about the 2G, but I'm not sure it is much help. However, the 2G's have a problem with the connectors becoming loose and causing problems - even fires.

I'm not saying that you need to change to a 3G, but if it was me I'd seriously consider it. I think you either have connector or alternator problems, and I think it is probably the connectors. They lose their tension, which causes heat, which reduces tension, which causes heat, ....

But, you said you replaced and soldered the plugs to the alternator. Maybe you've already addressed this issue?

Yeah I have the regulator mounted to the alternator. Yes I did replace both plugs soldered them in i have also checked to make sure I have not switched wires up when replacing them. The only thing that i haven't changed on that set of wiring is the inline fusible link. The way I understand it is that the link is just a smaller gauge wire. My thought is that i may have some broken strands of wire so the voltage maybe there but not the amperage. I don't know Im vary mechanical kind of person not electrical. My father has been trying to help with the electrical.

[Gary Lewis]

Yeah I have the regulator mounted to the alternator. Yes I did replace both plugs soldered them in i have also checked to make sure I have not switched wires up when replacing them. The only thing that i haven't changed on that set of wiring is the inline fusible link. The way I understand it is that the link is just a smaller gauge wire. My thought is that i may have some broken strands of wire so the voltage maybe there but not the amperage. I don't know Im vary mechanical kind of person not electrical. My father has been trying to help with the electrical.

I think it is acting like a bad connection. In other words, it works until the current gets to a certain point, at which the connection drops the voltage and sends the system bonkers.

Grasping at straws, have you checked that the alternator's case is grounded well? Perhaps put a ground wire on it?

How about the cab ground? That goes from the engine, usually the back of the intake manifold, to the firewall?

[Steve83]

...intermittent charging problem. It seams if

I drive during the day the alternator puts out enough power to charge. Acts like alternator is putting out required voltage (13.8-14.3). When I drive at night with a load such as headlights, heat, or wipers on it has a tendency to stop charging. It will kick in and out intermittently while driving. Sometimes you can drive a good distance before it will stop charging. When it does stop charging then it may kick back in but it may also take a while before it starts charging again.

...

Replaced alternator 3 times

That's essentially identical to my mother's '74 LTD wagon back in the early 80s. It was a nightmare. No shop she took it to could figure it out, and I had virtually no auto repair experience (or interest) at that time. One shop sold her a red battery cable because they told her the 2 black ones were the problem. After sitting on the side of the highway for an hour or so waiting for someone to stop & help, I started poking around & noticed that the (~3rd new) alternator was at the limit of its adjustment for belt tension. No one had replaced the (newish) belt, and it was too big. At low loads or low RPMs, it could keep the alt spinning enough to charge. But at highway speeds or high loads (A/C, lights, etc.), it would slip (without squealing) and the battery would discharge until there wasn't enough voltage for the ignition system to work.

Check the belt tension.

The alternator is the 2G...

Regardless what else you find or do, I highly recommend swapping to the 3G. It's cheap, easy, and could prevent the truck from catching fire. Gary has some pages here that explain how.

Had the battery tested good

What brand, group size, and build date? How exactly was it tested? This type is the only one that Ford, most other automakers, and most battery mfrs. accept:

https://supermotors.net/getfile/830812/thumbnail/mdxp300.jpg

Checked all the battery grounds

Until you list each one you checked, we can't confirm that you got "all" of them. How exactly did you check them? Pics of the truck & what you're working on would help us help you:

http://www.supermotors.net/forums/thid-5972-how-do-i-post-pictures-sounds-and-or-videos

Replaced a new start solenoid because I had a new one sitting around.

That's risky. New parts are not necessarily good parts, and disturbing things unnecessarily on an antique vehicle can create new problems.

BTW

A starter solenoid is an integral part of the starter, and your truck wasn't built with that kind of starter. The thing on the inner fender near the battery is the starter RELAY.

https://supermotors.net/getfile/285644/thumbnail/starterexploded.jpg

...replaced random wires that may have been messed up.

Even more risky. How exactly did you replace them? With what? How did you choose the ones to replace?

Tried a different computer...

The EEC has nothing at all to do with the charging system. When it had no effect, did you put the original back?

My thought is that i may have some broken strands of wire so the voltage maybe there but not the amperage.

If that were the case, the fusible link would have burned through, and the alt. would never work. If the alt. comes on at all, there's nothing wrong with the fusible link. But all the heavy terminals in the charging system need to be clean & tight:

https://supermotors.net/getfile/955475/thumbnail/26winchrelays.jpg

What do the battery terminals look like?

https://supermotors.net/getfile/723279/thumbnail/07done.jpg

[RustedJunk84]

I think it is acting like a bad connection. In other words, it works until the current gets to a certain point, at which the connection drops the voltage and sends the system bonkers.

Grasping at straws, have you checked that the alternator's case is grounded well? Perhaps put a ground wire on it?

How about the cab ground? That goes from the engine, usually the back of the intake manifold, to the firewall?

All the normal grounds are on it. I may try to add some more to see if anything changes. Driving today seemed as if it had a surge to it like a bad ground. Thanks for the thoughts tho

[RustedJunk84]

...intermittent charging problem. It seams if

I drive during the day the alternator puts out enough power to charge. Acts like alternator is putting out required voltage (13.8-14.3). When I drive at night with a load such as headlights, heat, or wipers on it has a tendency to stop charging. It will kick in and out intermittently while driving. Sometimes you can drive a good distance before it will stop charging. When it does stop charging then it may kick back in but it may also take a while before it starts charging again.

...

Replaced alternator 3 times

That's essentially identical to my mother's '74 LTD wagon back in the early 80s. It was a nightmare. No shop she took it to could figure it out, and I had virtually no auto repair experience (or interest) at that time. One shop sold her a red battery cable because they told her the 2 black ones were the problem. After sitting on the side of the highway for an hour or so waiting for someone to stop & help, I started poking around & noticed that the (~3rd new) alternator was at the limit of its adjustment for belt tension. No one had replaced the (newish) belt, and it was too big. At low loads or low RPMs, it could keep the alt spinning enough to charge. But at highway speeds or high loads (A/C, lights, etc.), it would slip (without squealing) and the battery would discharge until there wasn't enough voltage for the ignition system to work.

Check the belt tension.

The alternator is the 2G...

Regardless what else you find or do, I highly recommend swapping to the 3G. It's cheap, easy, and could prevent the truck from catching fire. Gary has some pages here that explain how.

Had the battery tested good

What brand, group size, and build date? How exactly was it tested? This type is the only one that Ford, most other automakers, and most battery mfrs. accept:

https://supermotors.net/getfile/830812/thumbnail/mdxp300.jpg

Checked all the battery grounds

Until you list each one you checked, we can't confirm that you got "all" of them. How exactly did you check them? Pics of the truck & what you're working on would help us help you:

http://www.supermotors.net/forums/thid-5972-how-do-i-post-pictures-sounds-and-or-videos

Replaced a new start solenoid because I had a new one sitting around.

That's risky. New parts are not necessarily good parts, and disturbing things unnecessarily on an antique vehicle can create new problems.

BTW

A starter solenoid is an integral part of the starter, and your truck wasn't built with that kind of starter. The thing on the inner fender near the battery is the starter RELAY.

https://supermotors.net/getfile/285644/thumbnail/starterexploded.jpg

...replaced random wires that may have been messed up.

Even more risky. How exactly did you replace them? With what? How did you choose the ones to replace?

Tried a different computer...

The EEC has nothing at all to do with the charging system. When it had no effect, did you put the original back?

My thought is that i may have some broken strands of wire so the voltage maybe there but not the amperage.

If that were the case, the fusible link would have burned through, and the alt. would never work. If the alt. comes on at all, there's nothing wrong with the fusible link. But all the heavy terminals in the charging system need to be clean & tight:

https://supermotors.net/getfile/955475/thumbnail/26winchrelays.jpg

What do the battery terminals look like?

https://supermotors.net/getfile/723279/thumbnail/07done.jpg

I have been thinking of upgrading the charge system but I was wanting to fix the problem before trying something new.

I have put a new belt on it also I just forgot to mention it.

As far as the grounds I have checked the ones I believe could be a problem. Such as battery ground cable, may just buy a new replacement one but I would believe the one on it is still good, it's a few years old.

I've checked the groinds by the headlights thinking that they may have created a high resistance since it seams to fail when headlights are on. It hasn't really failed in the daylight. Also checked the grounds by the computer and in the cab area.

I tried the solenoid because they are common fails in these trucks. Replaced with one that I already knew was a good solenoid.

The battery was just the normal Auto Zone charge and check. Also had O'Reillys check it with their hand held.

The part about fixing odds and end wires. As I went through tracing wires and looking for a short I would fix anything that looks as if it would fail. Such as wire casing being messed up or a corroded end or something of that nature.

I have owned this truck for 17 years and it's been my daily for most of the time. It has never seen a repair shop. But this problem has got me stumped.

Thanks for your help

[Gary Lewis]

I have been thinking of upgrading the charge system but I was wanting to fix the problem before trying something new.

I have put a new belt on it also I just forgot to mention it.

As far as the grounds I have checked the ones I believe could be a problem. Such as battery ground cable, may just buy a new replacement one but I would believe the one on it is still good, it's a few years old.

I've checked the groinds by the headlights thinking that they may have created a high resistance since it seams to fail when headlights are on. It hasn't really failed in the daylight. Also checked the grounds by the computer and in the cab area.

I tried the solenoid because they are common fails in these trucks. Replaced with one that I already knew was a good solenoid.

The battery was just the normal Auto Zone charge and check. Also had O'Reillys check it with their hand held.

The part about fixing odds and end wires. As I went through tracing wires and looking for a short I would fix anything that looks as if it would fail. Such as wire casing being messed up or a corroded end or something of that nature.

I have owned this truck for 17 years and it's been my daily for most of the time. It has never seen a repair shop. But this problem has got me stumped.

Thanks for your help

I would do the voltage drop test, assuming you can get it to fail sitting still. That's described here: Electrical/Voltage Drop Test.

My guess is that you have a bad cable or connection that causes the voltage at the alternator to rise w/o the voltage at the battery rising. This can be either the charge cable or the ground.

So if you can get it to fail sitting still, perhaps after you've driven it with the lights on, put your meter from the alternator's case to the battery's negative terminal and put the meter on the 20v scale. If you show more than a tenth or two of voltage then you need to find out where the problem is. Similarly test from the alternator's output terminal to the battery's positive terminal.

This will show if you have a voltage drop in either leg of the circuit.

[RustedJunk84]

I would do the voltage drop test, assuming you can get it to fail sitting still. That's described here: Electrical/Voltage Drop Test.

My guess is that you have a bad cable or connection that causes the voltage at the alternator to rise w/o the voltage at the battery rising. This can be either the charge cable or the ground.

So if you can get it to fail sitting still, perhaps after you've driven it with the lights on, put your meter from the alternator's case to the battery's negative terminal and put the meter on the 20v scale. If you show more than a tenth or two of voltage then you need to find out where the problem is. Similarly test from the alternator's output terminal to the battery's positive terminal.

This will show if you have a voltage drop in either leg of the circuit.

I will try that if I can get it to fail. Maybe on my way home in the morning.

[RustedJunk84]

I would do the voltage drop test, assuming you can get it to fail sitting still. That's described here: Electrical/Voltage Drop Test.

My guess is that you have a bad cable or connection that causes the voltage at the alternator to rise w/o the voltage at the battery rising. This can be either the charge cable or the ground.

So if you can get it to fail sitting still, perhaps after you've driven it with the lights on, put your meter from the alternator's case to the battery's negative terminal and put the meter on the 20v scale. If you show more than a tenth or two of voltage then you need to find out where the problem is. Similarly test from the alternator's output terminal to the battery's positive terminal.

This will show if you have a voltage drop in either leg of the circuit.

This charging crap is killing me.

I checked for voltage drop Tuesday morning when I got off work but the alternator wasn't failing at that time. I still ran the test came out with .02 from alternator case to negative batt post. I did the same test on the positive side but wasn't sure if I was getting the right reading.

Wednesday morning I did the test again with same results but some times intermittently I was getting a 2.21 reading so I wasn't sure if I was doing the test right because I never got a constant. This time the alternator was failing.

I did find that I got it to fail a few times if I just turned the heater on before start up. As I messed around under the hood I did notice that the black and orange wire that leads to the start solinoid was getting pretty warm almost hot on the side of the solinoid to the inline fuse link. I have noticed that before so I cut the link out replaced it with new fuse link soldered in. Haven't got it to fail again so I will keep my eye on it.

I did go and buy some new battery ground cables and a new battery positive cable. Also bought some ground strap of body grounds. But as we know one thing at a time. Thanks again for the help keep you posted.