I've been researching my No Charge symptom for several weeks and have tried multiple methods with no success. I will include as many details in this post to try to narrow it down as much as possible. Here's what I have: 1978 F250 Ranger Lariat Trailer Special, 400 6.6L, she's a beauty in the rough. Here's what IT has (new): Starter Motor, Starter Solenoid (gold plated), Alternator, Belts, Voltage Regulator, Battery (interstate 65), Battery Cable, several new and additional Grounds, Ignition Control Module, Highbeam Switch, Spark Plugs, S.P. Wires, Cap & Rotor, Fuel Pump and many many more that are irrelevant to my diagnosis.
​​​​​​Now for some brief history. I bought the truck 4 years ago and it wasn't running. I adjusted the timing and tuned her up real good, like my ex, and got her running good right away. Drove her daily for a year and a half then got a 94 Ranger for commuting while parts in the 78 started failing. The 78 sat a few months until I moved an hour away, then she fired right up with a new ALT when I drove her to my new house. Then she sat for a year, and she didn't like to start. So I rebuilt the Edelbrock Carb. Each time I fired her up she needed a trickle charge to start again after driving it, but not when it would sit at idle in the driveway.
So for the last month and a half I have thrown new parts in her and run diagnostics. Only registered 12.6v at ALT with another new ALT. Rewired all connections at ALT and V Regulator. Registered 14.4v. Same symptoms. New battery, same symptoms. Fires up on fresh charge, acts dead after driving it. Yesterday I had my friend help me with electrical diagnostics with a manual in front of us. Tested everything with a meter and everything checked good. All wires in the charging system had good resistance/continuity/voltage after the repairs I had made. The only questionable numbers I saw were when I jumped the A and F terminals at the regulator connector with ign on eng off I got 11.6v. Is this acceptable voltage drop here (base volt 12.4)?? Also with A and F jumped with the eng running under load I got 18v, which I believe anything over 1/2v above base reading is acceptable. The only things I haven't replaced are the Ignition Switch and also the Auxiliary Battery Relay, which looks crusty. I've tested for battery drain and registered 0.0>0.1 amp draw. I'm stumped. Especially after we tried to jump it with a 200 amp jumper, and bypass the starter solenoid with jumper cables to no success after driving her around the block. Please share any input any of you may have whether it be a simple suggestion or a lesson from your own experience with similar diagnostics. I appreciate you taking the time to read this, and I hope I got your gears turning now :P

 

Welcome to the site!

Does it have an ammeter or a warning light? If it's a light, and the bulb is burned out, maybe that might cause a no-charge.
Also look for a Wide Open Throttle switch (or the wires for one) on the carb near the driver side front carb stud and nut. I had an '84 Capri RS 5.0 which had one of these, and when I had the carb off to rebuild it, I put an extra one on there so I could drive it. The extra carb didn't have this switch, and the system wouldn't charge without it. I followed the Haynes schematic, and wired up my own charge circuit. Long after the original carb was back on, I found out why it hadn't been charging, and removed my added charging system wires, and it still worked.

 

It has the ammeter gauge, but I'm not confident it is working properly. That is something I haven't checked yet.

 

The stock ammeter gauges are notorious for not giving a reading. Have you given a thought to a voltage gauge? They're more dependable and what you really want is a voltage reading anyway....

Since you set the alternator to full field (18 VDC) by jumping those terminals, that means it tested out good.....and if she's still not charging after that test, it means the regulator is shot...."new" doesn't mean good these days.

With the vehicle off, test the battery voltage on the posts....fire her up and test the voltage at the posts (again) and then at the cable connections. If there's any difference, the cables need to be ohmed out....

If you still think you have a parasitic drain, disconnect the (-) battery cable for the night and reconnect it in the morning. If you see a spark, the battery drain is most likely from the starter solenoid....whack it a few times....that might free up the contacts inside. If you feel it needs replacing again, get the better quality one/Motorcraft - usually more dollars, too.

Again, "new" doesn't necessarily mean "good."

 

I have a 1979 F 250 4x4. I had the same problem a few years ago. Trace your wires from the solenoid over to the alternator, you will find a 3 way connection in the larger black wire. This was my problem the connection went bad, once I repaired it , I was good to go. I actually condemned a couple of good alternators because of this.

 

This is the diagnosis guide i followed. I did have a couple of these symptoms, but since i have fixed them i no longer have any of these symptoms on this list. Following these steps leads me to conclude i have no bad components. So i have tested each component in the system to be fully functional, the problem is my (new)starter wont even crank once after its been driven. Not even when i jump it directly with 200 amp plug in jumper or 1000 amp portable jumper, not even when bypassing the solenoid with jumper cables. Would frayed wiring cause this type of battery drain only while the engine is running? Say a rat chewed some wiring, would that create this headache of a symptom, where the battery would only drain excessively when accessories have power? What would be the best way to track something like that with a multimeter?

 

I have been wondering about that exact location in the wiring. Today I will run all new wires, connections, and splices between the regulator, solenoid, and alternator and see how she charges afterwards. I just figured since my readings were good on my multimeter I didn't have to mess with those splices, but I'll do it anyway so I can eliminate that being the potential issue. Thank you for confirming my suspicion of that splice!

 

Where were you measuring the 14v from when the engine was running? Alternator or battery? Normally it should not matter as your battery cables should show the same voltage no matter where you're taking your reading, but I wanted to know more of what you were testing.

If you're getting that 14v consistently, then your alternator is working. Period.
If it's not consistent though, and you see it drop to 12v or thereabouts then something is up with the system.
I would not necessarily be replacing wires either. Even though you could be fixing a bad one (and that's a good thing!) you could also be introducing other inconsistencies from having more splices present than you had before. Meaning you have more things to check and keep track of.

If you were measuring that 14v at the alternator but not seeing that same reading at the battery (I'm not sure that's possible, but I'm not often surprised anymore either!) then something is wrong between the two.

Got a pic of your starter relay area under the hood? Just like to see if anything is obvious.
You've already checked pretty much everything off the list it sounds like, so I'll just reiterate what was already said (didn't I just say that?) that new does not always mean good. Been there, seen that many times.
Two of the most commonly failed "new" parts in fact, are starter relays and voltage regulators.

For your reference, you should see these readings at the voltage regulator:

1. F = Orange wire and zero volts with the key OFF.
2. S = Green w/red stripe wire. Should see full battery voltage with the key ON.
3. A = Yellow wire (usually two of them) should have full battery voltage at all times.
4. I = Unused on trucks with alternators. If you have a wire there, check it out to see why you have a wire there.

Wiggle the wires to see if those readings change. If so, the wires and/or connections are bad.

You did say you replaced the battery cables and added new grounds?

Good luck.

Paul

 

Once in a while electricity will make you scratch your head. I am a Power Lineman by trade , and have run into it more than enough times to pull my hair right out. You see , checking voltage at all the points in a system only tells you if power is available, it does not tell you if wires and connections are any good, they could be so rotten that only 1 strand of wire is any good. That’s enough to show voltage at a contact point. If the conductors inside the jacket have rotted enough they just won’t carry the load. That is why I was having problems as I explained earlier. That 3 way splice wasn’t carrying the current from the alternator to the battery. It goes to the near side of the starter solenoid. Now if you take your multimeter and check the resistance of the wire ( ohm check) then that will tell you if it is any good, but remember the wire has to be disconnected from both (all) contacts.

 

hey Paul,
I was getting the same V at the alt and battery, but the wires seemed a bit burnt when I stripped them for new connectors. I also revealed some hokey splicing between alt and reg when I untapped the wires, so I wanted to rewire this for multiple reasons at this point. I just checked the voltage before work at the S circuit and got 1V less than at the battery. So it only had 11.8v at this S circuit with ign on eng off while the battery had 12.8v. It sounds like my issue is within this circuit

 

I don't know if that voltage drop is acceptable though, and I haven't been able to find anything specific enough about that. In the diagnostics chart it only mentions that the S circuit is acceptable to be 1/2v above the battery voltage with the engine running under load. Which it was when I tested it eng on under load. But with eng off ign on, the voltage drop is 1v. So now my question is, is this an acceptable voltage drop or is my issue indeed in the S circuit?

 

Ok, time for some popcorn and soda. But no movie yet...


I'm assuming that by "under load" they mean the electrical system? Like having the lights, heater and flashers all on at the same time? Hope so!

With no load, I don't like any voltage drop frankly. But since this "S" circuit is just energizing the voltage regulator anyway, I would think that 1-2 volts less than battery would still get the job done. However that drop indicates something wrong with the circuit between the key and the regulator and probably should be fixed just on principal.

Is this with the then-new battery? Or is the battery new as of this week?

So far, so good...

I would either figure out how to rig your volt-meter up while driving, or just get one of those digital meters that plugs into a cigarette lighter so you can monitor what's going on when you drive it.
That 14.4 is perfect for charging a (good) battery. Anything below about 13.2 or so is not very good.
Maybe when you put it in drive and run around the voltage is dropping.

I think someone mentioned testing resistance on a main battery cable not being a reasonable test for high-amp performance. I'd agree with that.
Both of your main cables are new? What about the charging cable/wire from the back of the alternator to the starter relay/battery? Is it the original Black 10ga wire? Or did you replace that as well?
If you're measuring 14v or above at the back of the alternator, then again at the starter relay, then again at the battery, then the battery is charging or you have a bad battery.
If that voltage drops under some circumstances however (such as while driving), for whatever reason, then the battery will go dead.

Of course, we come back to the new reality of "just because it's new does not mean it's good" and the fact that even a second or third battery could be defective. Not common at all to have two in a row, but it's not uncommon at all to find you've bought a bum battery.
Battery cables fall under the same spell unfortunately.

This might not be your issue, but it always bears mentioning again and again. But again again, whenever you're reading 14 or more at the battery cable, your charging system and associated wiring is working. At that point it falls back to the battery.
Did you kill this battery at any point during this? Well, obviously it's going down to the point it's not starting, but have any of those times had the battery deader-than-a-doornail? If so, the battery should be suspect now.

Where did you get that reading? At the battery, or at the wire from the regulator? If the Orange (or whatever color yours is) F wire, then that might not be a problem.
If you saw that at the battery or alternator, where you previously saw 14v, then that is a problem.

If it's at the F wire, then yes. It does not produce the full battery voltage at the output of the regulator during normal use. There is a drop inside the regulator itself or your alternator would always be putting out it's maximum. Not good for anything except for brighter headlights that die sooner!

Normal. But you do want more than 1v above battery for reliable charging. Closer to 2v is good.

No problem yet. Easy to check the wires coming out of the switch to see if this is where any drop is. Input wire should have battery voltage, output wires should too. Anything more than, let's say a half a volt is worth keeping an eye on. Anything more than three-quarters of a volt would need dealing with now to get that back up to less than a half. Prefferably as close to full battery voltage as you can get.
IN a perfect world you would want full system voltage at every point in the system. But that's not always the case when you get to longer runs of wire and more connections where each adds a bit of loss. But in our cases, places like the ignition switch are pretty important, being kind of in the middle of all the circuits, and should be seeing as close to full voltage as you can reasonabley expect from several feet of wire.
I'd like to see less than a tenth of a volt drop at those points.

Should be ok since it's not necessarily causing any issues with the main system, but it's still worth cleaning up for use. Do you use an auxiliary battery at this tine?

Seems a bit high maybe, and less would be good. But that's not a deal breaker right there and would only drain the battery when sitting. NOT when registering a 14.4v system charge.

It's not hard to see this on a normal rig if you can't guarantee that the rig is putting out it's full rated 200 amps. But if your starter (a new one you said?) is not a good one, it can easily need 300 amps to crank and start the motor. Perhaps you should revisit the starter and cables? I was leading up to that anyway.

And speaking of heat... Do you have headers? What is the symptom after driving? Just won't crank? Did you check voltage before cranking to see if the battery still had 12.6 or did you just consider it dead because it would not crank the starter?
I don't remember if you touched on this, but this is critical to your search. If the battery is indeed dead, that's one thing. But if it's simply not capable of spinning the starter motor, you could be looking more directly at:
1. Excessive heat. From headers maybe?
2. Weak starter. As said, "new" ain't necessarily good.
3. Bad cables? Heat is their enemy.
4. Too much ignition timing. Cold starts not a problem. Not starts, not so much...
5. Weak battery. They don't like heat either.
6. Something amiss with the engine itself. Not as likely since it sounds like it runs pretty decently. But not to be completely ignored either.

[QUOTE=Austin W;17514941]I was getting the same V at the alt and battery...

So far, so good. Again.

[QUOTE=Austin W;17514941]...but the wires seemed a bit burnt when I stripped them for new connectors.

Very bad sign, but how bad were they burned and how far in? Were you able to strip them farther down to good wire or were they too short?

Only possible correct choice in this case. Bad splices mean headaches and hair pulling to find present and future problems. I've been very diligent with splices all my car life, but have found several bad ones I made, as well as one that was decent but not weatherproofed that kicked my butt for months!
Outdoor wire nuts would have been an improvement!

It's at least part of an issue. But like I said your regulator should still work (in theory, because I've never seen that specification either) with 11v to trigger it.
But definitely dig into it. Go back to the key switch to see if the drop is there. If not, then the wire and it's connections are failing.

Good luck. Let me know what you think about that whole "heat" thing mentioned earlier.

Paul

 

I really appreciate all of your input, I will try to address all of your questions. If I don't, I will respond more later on. Excessive heat is a great suggestion, I do not have performance headers however and the starter wire is secured to the frame away from the heat as much as possible. I have certainly questioned the integrity of the new starter so I will be investigating that a bit more in the near future. I just bought a few feet of 1/0 wire. Everytime I pull into my driveway after driving around I check the voltage at the battery before and after I shut the engine off. My new battery hasn't read below 12.4v yet, it usually stays around 12.6v, I've had it almost a month. Before that I had just bought a used battery from a junkyard that tested good, but came to the conclusion I still needed a new one after I experienced this same scenario. That battery is now my aux battery because I believe it is still good now. This is my 4th battery. 3r alternator. 2ND voltage regulator. It does have a newer battery cable, I replaced it before it sat for a while.
I think ignition timing is something I need to investigate a bit more. Whether it is the issue or not, I am the one who set the timing to get it running initially years ago when I bought it. And I'm not a timing expert to say the least, but I have a friend who is and will have them revisit my ign timing with me. I will share a few recent photos, they don't include my most recent repairs but you'll get the idea. I have even wire loomed my spark plug wires incase they are grounding near any contact points with metal parts. I will probe around some more when I get home and check back here later.