Total electrical blackout

[larrym]

'64 Sport Fury with 440/727, new to me, rotisserie resto 10 years old. BH has been removed/bypassed, external VR, dash ammeter is not working. Car has quit on me, once while driving, total loss of electrical, no lights, nothing. Jiggled battery pos cable and it came alive. Shortly after while idling in my driveway same thing happened, jiggle fixed it. I found the Bat wire on the firewall relay was a little loose, tightened it up. Checking battery voltage running 12.57, revving, no change. Alternator doesn't seem to be producing, had it tested, tested good. If I quickly pull the + cable from the battery, vehicle dies.

I don't know how to test the alternator on the vehicle, but don't see it putting out any voltage. There are two connectors on the rear, one at 12 O/Clock another at 2 O'Clock, both are labelled FLD. I see some posts say the 2 O'Clock connector goes to ground on the alternator, this doesn't seem like a good idea to me.

I have a new VR and and relay on the way, doing wholesale parts replacement for now. Question, will the ammeter being ions stop charge to the battery? Can it be bypassed and how, or what's the work-around? I see references to bypassing it but not why or how. I can't find a guessable link anywhere in the system...yet...but still looking.

Thanks, Larry M.

 

[pnora]

I would be looking real close at the bulkhead connectors.

 

[larrym]

The BH connector has been removed/bypassed, wires routed through the firewall to under dash. Haven't removed the dash to access the wiring there yet...

 

[Jerry Hall]

If you pull the positive cable and the car dies the alternator is not charging the battery.
You stated, "I see some posts say the 2 O'Clock connector goes to ground on the alternator, this doesn't seem like a good idea to me". If the wiring is stock you do need to ground the one field post unless its been updated to the later voltage regulator for a dual field alternator. I'm just guessing, but I don't think that's your only problem.

 

[larrym]

Thanks Jerry. This is a new alternator and it tested good. I assume something in the system is breaking the charge function to the battery since the alt is good. I'm just looking for ideas. The wiring is stock, only one green wire at the field connector on the alt and one heavy black on the output stud.

 

[dadsbee]

"Dash amp meter not working" could be the hint....

 

[Jerry Hall]

Thanks Jerry. This is a new alternator and it tested good. I assume something in the system is breaking the charge function to the battery since the alt is good. I'm just looking for ideas. The wiring is stock, only one green wire at the field connector on the alt and one heavy black on the output stud.

New alternator. If it has provisions for 2 field wires the second one does need to be grounded for the alternator to charge. The key word is new and even though the parts house says it's correct, they don't tell you that on the early systems with only one field wire, that the other side is grounded. I will bet that same alternator will also be correct for a 1970 as well. 70 was the first year for the solid state voltage regulator and dual field alternators.
@dadsbee has a good hint about the amp gauge being another problem.

 

[diesel_lv]

I'm thinking the same as @Jerry Hall , remove the insulating washer on one of the field posts n ground it.

 

[Some Car Guy]

i agree. That alt will not charge in a car wired for one field.

also make sure the vr has a good ground.

 

[larrym]

I'm still researching how to bypass the ammeter, just tie the two sides together from the back of the ammeter? At my age my age (76) by brain sometimes goes to left field...lol

If bypassing the ammeter and running another wire directly from the Alt out to the starter relay Batt terminal, what size wire and useable link is recommended?

 

[diesel_lv]

I'm still researching how to bypass the ammeter, just tie the two sides together from the back of the ammeter? At my age my age (76) by brain sometimes goes to left field...lol

If bypassing the ammeter and running another wire directly from the Alt out to the starter relay Batt terminal, what size wire and useable link

Are you running a high amp alternator w a lot of draw on it, stereo amps, fuel injection/electric fuel pumps, dual electric fans etc...? If not, no need to bypass ammeter. I did a full conversion so it's the same gauge, but the guts are a voltage meter. I have 120 amp alternator and a lot of draw on the system. I ran 0 gauge wire directly from alternator to battery and then the normal battery to relay/starter. Nothing runs from my alternator to the relay.

 

[larrym]

Are you running a high amp alternator w a lot of draw on it, stereo amps, fuel injection/electric fuel pumps, dual electric fans etc...? If not, no need to bypass ammeter. I did a full conversion so it's the same gauge, but the guts are a voltage meter. I have 120 amp alternator and a lot of draw on the system. I ran 0 gauge wire directly from alternator to battery and then the normal battery to relay/starter. Nothing runs from my alternator to the relay.

I ordered a 75A alternator, (thinking the original 60A was shot), no big draws in the system. It's my understanding from other posts that a faulty ammeter can be cause for the system to go dark, but maybe not associated with the charging circuit. I also have a new VR and starter relay on the way, nothing like wholesale parts replacement, eh?

Also, after pulling the dash panel, I only see a heavy black and heavy red wire on the ammeter, with a light grey wire off the red lug going to the back of the clock...go figure, but it doesn't match the wiring diagram I have from MyMOPAR, which doesn't surprise me.

I can't find any useable links under the dash or engine compartment...yet.

Thanks for your reply.

 

[440 PHIXX]

You can put both ring connectors on the same lug to bypass the amp gauge, to see if that is the problem.

 

[Some Car Guy]

For a 75 amp alternator, you would want an 8 gauge wire. That means the fuseable link needs to be a number 12. it’s always four wire sizes less than your wire size.

you can send it to the starter relay or the battery, doesn’t matter. The battery wire is running there so either place is really the same.

problem I foresee is we never cleared up if you have a dual field alternator and is it wired correctly. So what you have may well be ok. The voltage regulator needs to have a good ground as well or you are just spinning your wheels. I like to run a dedicated ground for that and the ecu box bec all it takes is a little corrosion and you’ve got issues.

As was said you can bypass the amp gauge by simply putting both wires on one stud. It won’t read all the current anyway once you do a shunt to the battery or relay.

 

[larrym]

For a 75 amp alternator, you would want an 8 gauge wire. That means the fuseable link needs to be a number 12. it’s always four wire sizes less than your wire size.

you can send it to the starter relay or the battery, doesn’t matter. The battery wire is running there so either place is really the same.

problem I foresee is we never cleared up if you have a dual field alternator and is it wired correctly. So what you have may well be ok. The voltage regulator needs to have a good ground as well or you are just spinning your wheels. I like to run a dedicated ground for that and the ecu box bec all it takes is a little corrosion and you’ve got issues.

As was said you can bypass the amp gauge by simply putting both wires on one stud. It won’t read all the current anyway once you do a shunt to the battery or relay.

I have a 'square back' alternator, two field tabs, one of which I have grounded to the case. I've replaced the regulator and starter relay, tied the ammeter wires together and how have charging to the battery, 13.2 0 13/7V at idle. I will put a #12 fuesable link or two in the system, one from the alt to relay, one down to the starter and another to the dash wiring (BH connector has been removed by previous owner). Probably overkill, but that's me..

I will also get an aftermarket voltmeter unless I can find a work around I've seen reference to recently to use the old ammeter gauge, it something exists.

Thanks for the help...

 

[larrym]

I have a 'square back' alternator, two field tabs, one of which I have grounded to the case. I've replaced the regulator and starter relay, tied the ammeter wires together and how have charging to the battery, 13.2 0 13/7V at idle. I will put a #12 fuesable link or two in the system, one from the alt to relay, one down to the starter and another to the dash wiring (BH connector has been removed by previous owner). Probably overkill, but that's me..

I will also get an aftermarket voltmeter unless I can find a work around I've seen reference to recently to use the old ammeter gauge, it something exists.

Thanks for the help...

Just not sure, is the connector for the grey and red wires in this photo a fuse link?

 

[Some Car Guy]

I don’t believe so. Looks like a ring connector going to the post.

 

[Dave6T4]

Don't just connect the two wires together on an ammeter post. This makes the ammeter energized. Bolt the two wires together, and then tape the $hit out of them.

 

[68gtxman]

@larrym Don’t ever think that the barrel connector on the end of a new battery cable has been properly crimped and tight. I found a friend’s 1968 hemi Roadrunner’s positive cable end was as loose as a goose, but when he installed it, it seemed tight to him. It ran fine for a few months and then it was hit or miss depending on the outdoor temperatures.

 

[69 origownr]

Just not sure, is the connector for the grey and red wires in this photo a fuse link?

View attachment 1346803

I believe the fusible link is connected to the Bat post on the starter relay.