'51 CJ3A electrical Issues

Jadinsmore1

Gear Grinder
Nov 7, 2020
10
Maryland
First Name
Alex
Willys Model
  1. CJ
Willys Year:
  1. 1951
Hello!

This is my very first post and it is about my very first Jeep, a 1951 3a. I’m going to try and explain what is going on as best as I can through the sequence of events I’ve experienced.

Quick background,134 Go Devil Engine, still 6v. Was converted to a solenoid start a la 3B instead of floor start.

About a month ago the Jeep, electrically, was running fine. It would start, I could drive it around, everything seemed fine as I worked on making it run and stop better. I had a 12v battery in it before I realized it was 6v, but everything seemed to work ok enough for me. One day it wouldn’t start, I thought it needed a jump (despite having a new 12v battery) so I jumped it and it ran. I had just rebuilt the carb and was making sure it all ran fine and all my linkages worked and then it died. I tried to start it again and it struggled to start even while hooked up to my truck through jumper cables.

I thought maybe I had cooked the starter because I could hear the solenoid clicking but the starter would not engage or do anything for that matter. I ordered a new starter, solenoid and made up a new cable that runs from the solenoid to the starter. Today I put it all together and it made the starter spin without me turning the key and eventually it just stopped. When I checked the battery it wouldn’t even read the voltage, but when I disconnect the wire from the solenoid to the starter then it reads over 12v on the battery.
The new solenoid is now no longer clicking when I bump the key.

What the hell is going on?
 

garcia63

Bigger Hammer
Jun 9, 2019
162
Corpus Christi, TX
First Name
Jose
Willys Model
  1. Pickup
  2. CJ
Willys Year:
  1. 1951
Here’s a diagram I relied on to get my 12 v m38 ignition wired up. Disregard the alternator if you have a generator and the red wire for the electronic distributor. B81160C5-44CF-469E-B998-B4F03081704D.jpeg
 

64CJ5

Bigger Hammer
Jan 2, 2015
87
N E Wyoming
First Name
Tom
Willys Model
  1. CJ
Willys Year:
  1. 1964
I wonder what 6V parts were compromised by putting a 12V battery in place of the 6V. I am sure any 6V light bulbs would not last with 12V's going to them. What other 6V parts or wires would now be out of service?
 

Jadinsmore1

Gear Grinder
Nov 7, 2020
10
Maryland
First Name
Alex
Willys Model
  1. CJ
Willys Year:
  1. 1951
So today I found that my battery ground wire was bad so I fixed that and I got my regular lights working again (I only have a few that work).

So now I have everything hooked up as it was and traced wires to see what went where and it all seems correct-ish, I mean it ran before. Neither my original or new solenoid will click when I try to start. They both did at one point.

Would a bad ignition coil prevent the whole system from working?
 

Jadinsmore1

Gear Grinder
Nov 7, 2020
10
Maryland
First Name
Alex
Willys Model
  1. CJ
Willys Year:
  1. 1951
Where are you grounding that negative cable to?

The negative cable is grounded to the body, in what I assume is the stock location. I cleaned the connectors and took a wire brush to where the cable contacts the body. I also cleaned the clamp where it goes on the negative post on the battery.
 

Jadinsmore1

Gear Grinder
Nov 7, 2020
10
Maryland
First Name
Alex
Willys Model
  1. CJ
Willys Year:
  1. 1951
Thanks guys! I’ll take a look at the engine ground strap and relocate my negative battery ground and see if that helps.

I can fix a lot of things, but electrical is just witchcraft as far as I’m concerned!

When my 3a first started dying it would just crank slower and slower until it stopped, but the battery wasn’t dead. Then just the solenoid would click once every time I turned the key.
 

Joe B

Well Oiled
Dec 17, 2012
1,814
Sandston, VA
First Name
Joe
Willys Model
  1. Forward Control
Willys Year:
  1. 1960
One of our most highly esteemed members, Pavel (@pavel6), introduced us to this noun/verb that perfectly forebodes the eminent frustration often encountered when dealing with the idiosyncrasies of properly directing electrons: "electrickery".

Do you have a multimeter or a test light?


1605095866659.png
1605093477889.png
 

Jadinsmore1

Gear Grinder
Nov 7, 2020
10
Maryland
First Name
Alex
Willys Model
  1. CJ
Willys Year:
  1. 1951
One of our most highly esteemed members, Pavel (@pavel6), introduced us to this noun/verb that perfectly forebodes the eminent frustration often encountered when dealing with the idiosyncrasies of properly directing electrons: "electrickery".

Do you have a multimeter or a test light?


View attachment 86472
View attachment 86468

I do have a multimeter. Is there a sequence of areas that I should test one by one to determine the problem? I’ll certainly try and test the ignition switch
 

Joe B

Well Oiled
Dec 17, 2012
1,814
Sandston, VA
First Name
Joe
Willys Model
  1. Forward Control
Willys Year:
  1. 1960
Cool.
Physically check the grounds first. This thing was running okay for you not long ago.

Then make sure the solenoid "S" terminal is only seeing 12 V when the ignition switch is cranked to start. (With the transmission in neutral, wheels chocked, and bystanders at a safe distance.)

If you can't get the solenoid to click, pull it out and test it on the bench.
 

Jadinsmore1

Gear Grinder
Nov 7, 2020
10
Maryland
First Name
Alex
Willys Model
  1. CJ
Willys Year:
  1. 1951
Ok, so after a long hiatus from working on the Jeep (we don’t live in the same place yet) I put a little time in tonight. I checked all the grounds, moved the battery ground to a bolt on the engine, put in my new starter and starter cable from the solenoid. The solenoid clicks rapidly now, but no action from the starter.

Now what?
 

Jadinsmore1

Gear Grinder
Nov 7, 2020
10
Maryland
First Name
Alex
Willys Model
  1. CJ
Willys Year:
  1. 1951
Ok so I looked under the dash to check out the wiring situation per the diagrams sent in this thread and the wiring diagram in my factory manual and have decided I need to clean up the wiring, it’s all falling apart
 

ndnile

Well Oiled
All-Star
Oct 23, 2017
1,204
Northern CA
First Name
Doug
Willys Model
  1. Wagon
Willys Year:
  1. 1959
So today I found that my battery ground wire was bad so I fixed that and I got my regular lights working again (I only have a few that work).

So now I have everything hooked up as it was and traced wires to see what went where and it all seems correct-ish, I mean it ran before. Neither my original or new solenoid will click when I try to start. They both did at one point.

Would a bad ignition coil prevent the whole system from working?
Check that your solenoid is getting juice from the switch. Or if you are not comfortable with a voltmeter momentarily hold a jumper wire from your battery lead to the ignition post to see if it jumps to life. I’m assuming your solenoid is meant for 12 volts.
 
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