66 Fury Blows Fuse on start up

[cdnfury]

My car has a 30 amp modern fuse added to the red wire to the amp-meter inside the car , the fuse blows randomly on start up . I have power under the hood but no power to the dash.
I can't find any exposed wires in harness . Any suggestions on how to track down the cause would be appreciated.

 

[Knebel]

30amp isn't enough,I had the same setup and it kept blowing. I had a 40 and that worked okay. Ended up replacing it with a small 50amp circuit breaker!

 

[saylor]

you guys are gonna fry your cars. isnt this the wire/circuit that is supposed to have a fusible link on it?

rough math says thats 600W coming thru that wire 12v x50amp.

try not to die -

- saylor

 

[traintech55]

This is why the factories use a Fuseable link to protect the circuit. The voltage spikes are normal between startup, (discharge) and run, (charging).
CHANGE IT BACK TO A FUSEABLE LINK.

 

[Big_John]

This is why the factories use a Fuseable link to protect the circuit. The voltage spikes are normal between startup, (discharge) and run, (charging).
CHANGE IT BACK TO A FUSEABLE LINK.

X2

 

[mrfury68]

This is why the factories use a Fuseable link to protect the circuit. The voltage spikes are normal between startup, (discharge) and run, (charging).
CHANGE IT BACK TO A FUSEABLE LINK.

X 3
Check your bulkhead connections too. That is where the trouble usually starts. Old connections get corroded, generate heat from increased resistance, & get very brittle.

 

[cbarge]

Change it back to a fusible link!
Then add an extra wire from the battery stud of the alternator going to the starter relay with a fusible link. Use 10/12 gauge wire with a 14/18 gauge link. put the link at the starter relay battery stud for easy repair.
Why?
This piggy back takes 50% of the load AWAY from the ammeter gauge and the interior of the car will still function.
Problem on start up?
As a process of elimination,replace the starter relay. (cheap,good to have a spare anyways)
What else is in use on start up??
IGNITION SWITCH
Drop it down from the dash and test continuity and with a meter check to see if there is a short in it in start mode.
With over 50 years of use,I am leaning towards the ignition switch.
Keep in mind the switch is always HOT and no "fuses" per se for it.
If there is a short in it,that can trip the factory fusible link --or even worse--- burn the car to the ground.
There is a reason why Ma ran heavy 10 gauge wire to and from the ignition switch--lots of amperage.
Questions;
Are you running points or electronic ignition??
Single or dual field alternator??
Voltage regulator,is it the old mechanical type or retro electronic??
Keep in mind I am asking since they all run on switched power.
The ballast resistor is bypassed when key is in START MODE and feeds the coil and starter motor full 12 volts and the rest of the system I just mentioned.
Hope this helps...or buy me a plane ticket to Vancouver,LOL!!

 

[saylor]

you guys need to do the MAD mod at minimum, and nacho bypass is a plus. google it. go unhook your battery and dont drive again until you change it.

think we are kidding? this is car-death serious.

ever hear of or see a fried mopar from teh amp guage?

someone please post up a pic - i know someone has had one of these catch fire.

 

[traintech55]

you guys need to do the MAD mod at minimum, and nacho bypass is a plus. google it. go unhook your battery and dont drive again until you change it.

think we are kidding? this is car-death serious.

ever hear of or see a fried mopar from teh amp guage?

someone please post up a pic - i know someone has had one of these catch fire.

Over the years I have learned a good and quick repair for the "Bulkhead Connector" problem. I move my fusable link from the Starter relay to the battery line like they did after 1969. Then I remove the male and female connector on the main line in and out and replace it with a 12 gauge wire. No more hot spot to melt or catch fire.

 

[saylor]

@TT55 - are you leaving the amp gauge in dash connected? feeding 1 post only? bypassing it completely?

if i understand it how you describe - you just end up with a small piece splice wire thru the bulkhead? just rip off the terminal ends and splice up thru the bulkhead?

 

[traintech55]

@TT55 - are you leaving the amp gauge in dash connected? feeding 1 post only? bypassing it completely?

if i understand it how you describe - you just end up with a small piece splice wire thru the bulkhead? just rip off the terminal ends and splice up thru the bulkhead?

Yep, exactly. I remove the plug, take the male and female terminals out of the connector, and splice in a new wire with weatherproof insulation. Problem solved forever. Once you remove any chance for corrosion to impede the current flow, the overheating though the connector is gone and you have turned it into a solid connection.

 

[traintech55]

Once you have a solid wire from the starter relay into the bulkhead connector, splice into the wire to the ammeter. Then do the same to the wire going to the alternator. This is why you move the fuse-able link between the battery and starter relay. Solid wire will not overheat.

 

[saylor]

Catalog

MAD page for ammeter bypass

 

[saylor]

@TT did you leave your amp meter in dash and wired as factory?

I've heard of a bunch of ppl saying their nuts were loose - thats the 2nd worst ever possible time to have to say those words.

 

[traintech55]

@TT did you leave your amp meter in dash and wired as factory?

I've heard of a bunch of ppl saying their nuts were loose - thats the 2nd worst ever possible time to have to say those words.

Yes I left the ammeter in the dash, and yes the nuts behind the terminals were loose also. The harness in my 300 was so burnt up at the bulkhead, I had to replace the dash and underhood harnesses. That is why I modified the wiring so it would not burn up again. ALL IS FINE NOW,

 

[traintech55]

I've heard of a bunch of ppl saying their nuts were loose - thats the 2nd worst ever possible time to have to say those words.

You never want certain nuts tightened, WAY TO PAINFUL.

 

[cdnfury]

This is why the factories use a Fuseable link to protect the circuit. The voltage spikes are normal between startup, (discharge) and run, (charging).
CHANGE IT BACK TO A FUSEABLE LINK.

Change it back to a fusible link!
Then add an extra wire from the battery stud of the alternator going to the starter relay with a fusible link. Use 10/12 gauge wire with a 14/18 gauge link. put the link at the starter relay battery stud for easy repair.
Why?
This piggy back takes 50% of the load AWAY from the ammeter gauge and the interior of the car will still function.
Problem on start up?
As a process of elimination,replace the starter relay. (cheap,good to have a spare anyways)
What else is in use on start up??
IGNITION SWITCH
Drop it down from the dash and test continuity and with a meter check to see if there is a short in it in start mode.

With over 50 years of use,I am leaning towards the ignition switch.
Keep in mind the switch is always HOT and no "fuses" per se for it.
If there is a short in it,that can trip the factory fusible link --or even worse--- burn the car to the ground.
There is a reason why Ma ran heavy 10 gauge wire to and from the ignition switch--lots of amperage.
Questions;
Are you running points or electronic ignition??
Single or dual field alternator??
Voltage regulator,is it the old mechanical type or retro electronic??
Keep in mind I am asking since they all run on switched power.
The ballast resistor is bypassed when key is in START MODE and feeds the coil and starter motor full 12 volts and the rest of the system I just mentioned.
Hope this helps...or buy me a plane ticket to Vancouver,LOL!!

The car has electronic ignition , retro electronic regulator and how do I tell if its a single or dual field alternator ? The car still has the fusible link in place . The only reason I found the modern fuse was that the car died while I was driving it and after tracing wires I found the fuse added to the large red wire running to the dash. I replaced the fuse and it ran for a few days then the fuse blew when I turned the key. Thank you for the help.

 

[cdnfury]

My car has a 30 amp modern fuse added to the red wire to the amp-meter inside the car , the fuse blows randomly on start up . I have power under the hood but no power to the dash.
I can't find any exposed wires in harness . Any suggestions on how to track down the cause would be appreciated.

Thank you all for the advice .

 

[traintech55]

Thank you all for the advice .

Send me a P.M. and I will give you my number and help walk you through the repair.

 

[saylor]

props to the forum - saved 2 more cars from certain death by fire