No spark question

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bigtom

bigtom

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I have a 71 Dart with a 318... I have done the amp bypass and it is charging great. The problem is that last night when I tried to start her No GO... I used my trouble light and confirmed that there was no voltage to the coil when cranking. To get home I jumped from the battery to the coil and it fired right up. Am I looking for a feed from the ignition switch for this power? I have a schematic and will be working on her after work, but any hints or experiences would help.... THANKS

P.S. Ballast has been bypassed and I am running a Pertronix 2
 
There is a dark blue wire by itself at one end of the ballast resistor that is igntion power to the ballast when the key is in RUN. There should be a brown wire to the other end of the ballast that is igntion power direct to the coil when the key is in START, and another blue wire going from that end of the ballast to the coil +.

Check for 12v on the brown wire to the ballast when the key is in START:
- if OK, then the blue wire to the coil+ needs to be checked;
- if not OK, then check the brown wire connections back through the firewall connectors and on back to the ignition switch.
 
Use your voltage ohm meter and test for power at the ceramic resistor on the firewall. These things fail without notice. But it could also be the bulkhead connector or the ignition switch. The VOM will track it down for you.
 
To expand on what nm9 said

There are TWO ignition sources. On most these cars, the RUN line goes DEAD during cranking. The run line is the blue shown as IGN 1 on the diagram

The ONLY source of ignition power for start is the brown IGN 2. This is a simple circuit

It comes off a separate contact on the ign switch, goes through the bulkhead, and to the coil + side of the ballast.
 
bigtom said:
THANKS TO ALL!! I traced it, fixed a dead short and drove to work...
Click to expand...
Could you please tell me where the dead short was? Thanks.
I am going through this problem right now. my 73 would not crank so I left it in run position and tried to start by jumping the Solenoid. She would not fire up. Then the connector at the bulk head started smoking. I disconnected the battery and there is a definite short to ground now.
 
Can you take a pix of where the bulk head conenctor smoked? And then start a new thread and put the pix in that?
 
nm9stheham said:
Can you take a pix of where the bulk head conenctor smoked? And then start a new thread and put the pix in that?
Click to expand...
Okay thanks. I will try today. This car also has an MSD ignition system. The weird thing is that the Ballast resistor was left hooked up but never seemed to be a problem. The wire that smoked is definitely one of the 2 that go to the Ammeter. Myinitial guess is that I have to do the MAD bypass and possibly an ignition switch. I just don't know where to start.
 
Ah, OK yeah that is pretty serious. May be a short inside the ammeter, but the Mad Electrical articles should explain all of that to you. And, BTW, the request for a new thread is to avoid confusion; it is sometimes hard to follow just one problem!
 
nm9stheham said:
Ah, OK yeah that is pretty serious. May be a short inside the ammeter, but the Mad Electrical articles should explain all of that to you. And, BTW, the request for a new thread is to avoid confusion; it is sometimes hard to follow just one problem!
Click to expand...
I wiil start the new thread. I got the 3 connectors pulled in the engine bay but no sigh og Burning. I think the Fusible link was what was smoking. It feels pretty "spongy". It's real tight in there for pictures and to work on it.
 
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