67 no power to coil yet turns over

6t8stang · Oct 19, 2022

Hello all,

I have a 67 coupe. Everything was fine til this morning. I went to start car, it turns over but won’t stay on.

I’ve put new starter solenoid, coil with no start.

When I connect a hot wire from positive battery to positive coil, car starts and idles but starter stays on?

Any suggestions?

V8, standard ignition

wicked93gs · Oct 20, 2022

Stock distributor?

What is happening here is that wire 16 from the coil is not getting power from 16a from the ignition switch. When you jumper the coil directly from the battery, you power 16B, which turns into 262 and runs to the starter side of the starter relay...thereby activating the starter circuit. If you jumpered the coil after disconnecting wire 16 from the coil this would not happen. In particular though your problem is wire 16A which is a resistor wire running from the ignition switch to the coil that reduces the voltage from 12v to 9v. Chances are the resistor built into this wire fried and is not supplying power to the coil,

6t8stang · Oct 20, 2022

I ran a wire from ignition switch to + coil and had same effect. Car started but the starter stayed on.

It’s an msd distributor with NO box

6t8stang · Oct 20, 2022

Ordered new resistor wire, hopefully that’s the issue

6t8stang · Oct 20, 2022

wicked93gs said:
Stock distributor?

What is happening here is that wire 16 from the coil is not getting power from 16a from the ignition switch. When you jumper the coil directly from the battery, you power 16B, which turns into 262 and runs to the starter side of the starter relay...thereby activating the starter circuit. If you jumpered the coil after disconnecting wire 16 from the coil this would not happen. In particular though your problem is wire 16A which is a resistor wire running from the ignition switch to the coil that reduces the voltage from 12v to 9v. Chances are the resistor built into this wire fried and is not supplying power to the coil,

Thank you!

I jumped coil and disconnect wire 16 and car started and idled fine.

Hopefully pink wire is the culprit. Will be installing tomorrow I hope.

wicked93gs · Oct 20, 2022

6t8stang said:
I ran a wire from ignition switch to + coil and had same effect. Car started but the starter stayed on.

It’s an msd distributor with NO box

I can't remember if its the stock coil or the stock dizzy that requires 9v...you may not need the resistor in the wire at all....but I am not the person to ask about that....its been probably 20 years since I had a SBF in any of my classic mustangs at this point.

6t8stang · Oct 20, 2022

6t8stang · Oct 20, 2022

MSD distributor with no box.

6t8stang · Oct 20, 2022

Did more research….. apparently I can bypass pink wire all together. MSD recommends full 12v to perform “at its full potential”

6t8stang · Oct 23, 2022

I’m trying to bypass pink wire with a 16g wire from ignition to male plug under dash. My pink wire did not have bullet style connectors,Non tach.

What is and what do I do with the red w/brown stripe wire going into connector WITH the pink wire?

6t8stang · Oct 23, 2022

I’ve re read diagram multiple times… to confirm… pink wire and red/green wire join into a 4 plug rubber connector where it then turns into a brown wire that leads to “I” on the solenoid.

To bypass pink wire, I connect wire from ignition to coil. I can also disconnect brown wire since it wouldn’t be doing anything….

Am I wrong? Any hello is appreciated

wicked93gs · Oct 23, 2022

The brown wire is needed for the starter to turn over in "start" if you disconnect the brown wire your solenoid won't be able to supply power to the starter.

You can just splice directly around the resistor itself and be done with it if you need 12v. I couldn't tell you where in that wire the resistor is though....I rewired my car from scratch and I don't have a distributor so I never needed a resistor.

6t8stang · Oct 23, 2022

Now im more confused. I unplugged brown wire at solenoid and car starts fine.

wicked93gs · Oct 23, 2022

6t8stang said:
Now im more confused. I unplugged brown wire at solenoid and car starts fine.

Wire 32 also provides power to the solenoid. I guess 262 really is redundant. Why did you disconnect it though? I guess its irrelevant to jumpering around the resistor though. If I get a chance tomorrow I can pull out my factory '66 harness and take a look at it...it should be the same(or very close)

6t8stang · Oct 23, 2022

wicked93gs said:
Wire 32 also provides power to the solenoid. I guess 262 really is redundant. Why did you disconnect it though? I guess its irrelevant to jumpering around the resistor though. If I get a chance tomorrow I can pull out my factory '66 harness and take a look at it...it should be the same(or very close)

I only disconnected brown wire because other threads stated it was no longer of use.

I really hate wiring. It has been very frustrating. The smallest thing is keeping me from driving.

wicked93gs · Oct 24, 2022

6t8stang said:
I only disconnected brown wire because other threads stated it was no longer of use.

I really hate wiring. It has been very frustrating. The smallest thing is keeping me from driving.

Ah, that makes sense now. Since you are getting rid of the resistor wire, wire 32 will now provide a full 12v to the solenoid...with the resistor in place, the solenoid was depending on wire 262 to get full voltage(otherwise it would only get 9v) so it wasn't redundant after all. Just be aware if you ever go back to a stock distributor you will need to revisit the wiring at that time.

6t8stang · Oct 24, 2022

Wicked93gs…. Thanks for your help. The diagram has been very useful

67 no power to coil yet turns over

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