No spark again

J

JJrestore

New member
I am working on a 1937 ford club cabriolet and for the second time I am frustrated with the problem of no spark. After my initial problem with no spark, I replace the plugs, points, coil, plug wires, dist. caps, and rotor. The engine started and ran fine with a few adjustment required. I did not have the opportunity to drive the car as I was working on other areas to make it drivable. In that time I regularly started the engine, but the other day it would not start, NO SPARK AGAIN. I researched this subject again on this forum and received suggestions. One of those suggestions was to check the voltage from the coil wire to the coil (wire disconnected). it should read 3.5 volts. Mine read less that 1/2 volts. The thread did not mention what to check if the voltage was not 3.5 volts. That's where I'm at now. What to do next?
Thanks, Jakes.
 
If you are only getting 1/2 volt to the coil it sounds like the resistor may be faulty and should be replaced.
I would not try starting on 6 volts to the coil as it may or may not cause damage to the associated electrical components.

369400
 

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I would check the voltage to the resistor before I changed parts. You can check voltage to the ignition switch and from the ignition switch to the resistor. Voltage up to the resistor should be only slightly less than battery voltage.
 
This diagram was recently posted by Jim (Bubba) showing expected voltage through resistor and coil. Might be helpful in determining problem areas.
 

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Be sure you understand Bubbas sketch, he is showing the voltage drop across the resistor and across the coil. The voltage into the resistor should be near battery voltage.
 
I have a similar problem with my 39 Ford. Won't start, but about 3.6 to the coil. Run a jumper to the coil from the battery and it starts right up.
 
I agree with JSeery. Check your ignition/coil wire before the under dash resistor. Should be 6v. If less then 6v (or more relevant) current battery voltage your switch is corroded or bad.



If good then check after the underdash resistor. Less then 3v then the resistor is bad.


if you want to get 6v at startup look at a stock 6v ford tractor solenoid. Not your issue however.


no diodes needed. 4 pole with a straight 6v starter jumper built in.


https://www.completetractor.com/new...UAKpJaRiwXVx9nKrtHHgLjZfFVohQ82xoCTyQQAvD_BwE
 
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clean all your connections and add an engine ground. your dizzy might not be getting a good ground.


Wont effect volts to coil though on the wire itself, just good practice.


You don't have to disconnect any wires to check voltage (only amperage), just have to have a reliable ground source.
 
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