Need help guys , weird electrical problem

[ValerianMagnum]

Ok guys ! Very weird situation here...car was in a photoshoot yesterday , ran super good , and after a couple of minutes of driving and stopping the engine for different angles, the car just refused to start when it was shot off , started with a click sound ( starter ) and slowly lost all power...no more lights , volt gauges goes up 1 time out of 2 , no cranking , no power with test light , no burn smell...it never happened to me before , even took a brand new battery from my truck and it didnt do anything ...so , no power / no lights / no cranking but a strong battery , relay ? Electrical gremlin , ..what could it be ! stock 1968 fury III 318 / 727

 

[67Dart273]

Well it SHOULD be simple, as it should be confined to the major first part of battery distribution, AKA battery, post clamps, defects in a main cable, loose connection. You have a meter or even a test light?

If you think you read normal voltage, you need to load the system to show the problem. Try turning on the lights. Try jumpering the start relay. There are two large bare terminals on the start relay. The big stud/ nut comes from the battery, is always hot, and NOT fused. The smaller "square" terminal is the solenoid lead down to the starter. You can jam anything metal in between them, even a coin. See if it cranks, make certain it is in park.

If not, rig a test light or meter to the engine block and to that starter relay stud. You have power? Jumper the terminals. What happens. Power goes away? Relay chatters? Engine cranks?

If you lose all power there at the stud, move your hot probe to stab right into the battery POS post. If it shows power, load the system again, jumper the relay or turn on the lights. If you have power, move probe over to the actual battery clamp. If you lose it, you have a dirty post/ clamp. Same thing on ground clamp.

 

[Bewy]

Given the clues, I would think alt diode shorted. Try removing the alt wires.

 

[middleagecrisis]

No power to the fuseblock? I urge you to not start throwing parts at it until you figure out where your power stops from the battery. I fixed an electrical demon on my duster by cleaning grounds and replacing fuses. Your problem could be something as simple as my ground problem, or something like a bad starter or ignition switch. Get a test light and a wiring diagram ans start checking your power circuit. Electrical problems suck and you just have to put on your patience hat and work through it.

 

[ValerianMagnum]

Well it SHOULD be simple, as it should be confined to the major first part of battery distribution, AKA battery, post clamps, defects in a main cable, loose connection. You have a meter or even a test light?

If you think you read normal voltage, you need to load the system to show the problem. Try turning on the lights. Try jumpering the start relay. There are two large bare terminals on the start relay. The big stud/ nut comes from the battery, is always hot, and NOT fused. The smaller "square" terminal is the solenoid lead down to the starter. You can jam anything metal in between them, even a coin. See if it cranks, make certain it is in park.

If not, rig a test light or meter to the engine block and to that starter relay stud. You have power? Jumper the terminals. What happens. Power goes away? Relay chatters? Engine cranks?

If you lose all power there at the stud, move your hot probe to stab right into the battery POS post. If it shows power, load the system again, jumper the relay or turn on the lights. If you have power, move probe over to the actual battery clamp. If you lose it, you have a dirty post/ clamp. Same thing on ground clampi forg

Well it SHOULD be simple, as it should be confined to the major first part of battery distribution, AKA battery, post clamps, defects in a main cable, loose connection. You have a meter or even a test light?

If you think you read normal voltage, you need to load the system to show the problem. Try turning on the lights. Try jumpering the start relay. There are two large bare terminals on the start relay. The big stud/ nut comes from the battery, is always hot, and NOT fused. The smaller "square" terminal is the solenoid lead down to the starter. You can jam anything metal in between them, even a coin. See if it cranks, make certain it is in park.

If not, rig a test light or meter to the engine block and to that starter relay stud. You have power? Jumper the terminals. What happens. Power goes away? Relay chatters? Engine cranks?

If you lose all power there at the stud, move your hot probe to stab right into the battery POS post. If it shows power, load the system again, jumper the relay or turn on the lights. If you have power, move probe over to the actual battery clamp. If you lose it, you have a dirty post/ clamp. Same thing on ground clamp.

I forgot to mention but i did try it like that , it did it once ( sparked ) and when i started again later it was completly dead....now theres nothing anymore...no juice at all

 

[Dana67Dart]

Ok guys ! Very weird situation here...car was in a photoshoot yesterday , ran super good , and after a couple of minutes of driving and stopping the engine for different angles, the car just refused to start when it was shot off , started with a click sound ( starter ) and slowly lost all power...no more lights , volt gauges goes up 1 time out of 2 , no cranking , no power with test light , no burn smell...it

At first it sounded like you took more electrons out of your battery "bank" then you put back in.

But the new Good battery should have fixed that

Now I'm looking for bad connections that feed the car.

From the starter relay the power goes to the flushable link thru the bulkhead and into the car.
No power under load as described above suggests there is a bad connection in that path.

 

[ValerianMagnum]

At first it sounded like you took more electrons out of your battery "bank" then you put back in.

But the new Good battery should have fixed that

Now I'm looking for bad connections that feed the car.

From the starter relay the power goes to the flushable link thru the bulkhead and into the car.
No power under load as described above suggests there is a bad connection in that path.

Yes..ill check tomorow the bulkhead , nothing seemed melted , its all there ..im just very surprised that it refused to start and it went worst and worst to the point it even lost all power everywhere.

 

[Dana67Dart]

Any chance the replacement battery is bad?

Also look for damaged wire strands in a wire

A loaded voltage drop test is your best thing.