Coil issue - need help

[Ted G]

Looking for help on my coil wiring. I haven't started my engine yet, but I am anticipating a problem as the coil loses power after I turn the key to start. Not only does it lose power, it doesn't come back after I stop the starter. I have to go to the "off" position to get power back to the coil. I am using the supplied harness from FFR (Ron Francis). I tested the switch alone, IGN stays hot while turning the switch to start. So, switch is good. I do have a relay for the IGN but it is wired perfectly and I am using 1965 Ford Mustang switch. My guess, it's the relay, but any insight is welcomed. Hoping to have my first start this weekend.

Thanks in advance.

Ted

[Mastertech5]

Sounds like it might be the relay but I would check the relay connections and crimps on the spade wires. A bad relay ground is also possible. Seems like something isn't carrying the load but there really shouldn't be much load. Try without the relay by jumping across power in and power out terminals.

[rich grsc]

Why do you have a relay on the ignition ?

[BRRT]

What ignition controller are you using?

[Ted G]

Mastertech 5: I don't think it is the relay, i jumped the relay and still a loss of voltage.

Rich grsc: I am running a relay because I am using the 1965 Mustang switch instead of the FFR switch. The thought was the wires/terminals on this switch may not handle the loads of the IGN and ACC.

BRRT: I am running Pertonics Igniter II and Pertonics coil.


Side note, I am using an ac to dc devise that has no cranking power but provides 12v. I think maybe when I do try to crank, it is taking all the voltage and tripping the relay back to off. I am thinking I need a jumper from start over to the positive side of coil.

[BRRT]

"Side note, I am using an ac to dc devise that has no cranking power but provides 12v. I think maybe when I do try to crank, it is taking all the voltage and tripping the relay back to off. I am thinking I need a jumper from start over to the positive side of coil. "

I would bet this is it. The starter motor draws a lot of power. When you twist the key to the start position your 12VDC power supply overloads and the voltage drops way down or completely off.
Most DC power supplies have a protective circuit, called a "crowbar" circuit, that shuts off output when the current draw gets too high. It's likely shutting off, and that is why you aren't seeing the voltage come back when you turn the key away from the start position.

Measure the voltage at the output of the power supply and see what is going on there when you turn the key to start.

[rich grsc]

I've never heard of needing a relay on the ignition. I use the early Mustang switch, it is easily capable of the task, better than the FFR one.

[Namrups]

When I tried first start, my engine would turn over but not start. Quickly found out that the coil did not have any power. I ran a 12v wire from the ACC on the ignition to the plus side of the coil and it started right up. SBF with Sniper EFI.