help no power in run or accessory

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Joined
Jun 9, 2012
Messages
1,323
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Location
oklahoma
My Car
1973 mustang sportsroof - 351c 2v - fmx trans.
Guys and guys I need your help on this one. I have no power in the run or accessory position off of the ignitiin switch so I figured it must be the switch itself. I changed it out with no luck. The car will start in the crank position but dies immediately as soon as the key is released. The horn works, turn signals and headlights work as well. Where do I go from here thanks.

 
Thanks guys, the car will start and run if I connect the coil straight to the battery and start it, to shut it off the wire has to be disconnected.

 
Make sure the ignition switch is adjusted correctly. Connect a voltmeter to the + side of the coil, loosen the screws on the switch and move it back and forth and see if you can get voltage to the coil. If not pull the connector off the switch and see if you have any voltage to the switch.

 
Well after a few minutes with a multi-meter it turns out the red/green wire is the culprit, I probed it all the way back to the firewall grommet and it appears there is no voltage going through the wire. I will continue back further soon. Does anyone know the starting point of this wire or even better have a picture where it starts out? I am temporarily running a bypass wire and have the car up and running but would like to fix this correctly. Thank you all very much for the help.

 
Does the car have a factory tach / tach harness and the tach is unplugged???

The factory tachometer interrupts the voltage and senses current to run the tach.

You can "jump" the connector to start the engine with the tach not connected .

It's the same red/green wire inside the dash.

HTH,

Curtis

 
Thanks Curtis, no factory tach on this baby. I can see where the wiring harness comes through the firewall in to the interior but can't tell where everything goes, my 6 foot 250 pound body can't contort under the dash very well lol. If I had more of an idea of where everything went I might do a little better.

 
Thanks Curtis, no factory tach on this baby. I can see where the wiring harness comes through the firewall in to the interior but can't tell where everything goes, my 6 foot 250 pound body can't contort under the dash very well lol. If I had more of an idea of where everything went I might do a little better.
Mike,

It comes to the ignition switch mounted on top of the steering column. FYI, the wiring diagrams are on this site, under the Data tab on top of the page.

Curtis

 
Last edited by a moderator:
Your signature shows you have a Duraspark ignition, how is that wired up? I used to run mine right off the starter solenoid. The rear terminal on the solenoid is a booster circuit that is wired into the ignition circuit, you should have 7-ish volts there at all times with the ignition in run, 12v+ when the solenoid is energized.

 
I have it wired up with the duraspark box white wire to the "S" terminal, the ignition run wire goes in to a ballast resistor and out to the coil and red wire on the duraspark box. I also have a wire from the "I" terminal to the coil for full voltage during cranking. Everything is working fine now. Knocks on wood lol.

 
That sounds about right, but you don't want a resistor in the power feed for the D-spark. That should be a switched straight 12V source in run & start. When I used the D-spark boxes, I pulled the 12V right off the main harness side of the ignition switch connector on the pink wire, cleaned off some insulation and soldered the red wire feed to the D-spark to it, ran it through the firewall and out to the box. The I terminal on the solenoid will still provide the 12v power to the coil during starting and the S can signal the D-spark to retard the timing through the white wire.

Here's a good diagram, consider the ballast resistor shown to be the the stock pink resistor wire.

duraspark%20with%2010110.jpg


 
Hemikiller, just to comment on your wiring advice. The rear post on the solenoid has no voltage in the run position . . . except what is backfeeding from the ignition coil. That is why you see 7 ish volts. Unplug the wire and test if you doubt me.

 
Hemikiller, just to comment on your wiring advice. The rear post on the solenoid has no voltage in the run position . . . except what is backfeeding from the ignition coil. That is why you see 7 ish volts. Unplug the wire and test if you doubt me.
Nope, no doubt. I edited my post to clarify as I meant to put an S in there....

 
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