Forum Home Forum Home > CJ-2A Discussion Area > Tech Questions and Answers
  New Posts New Posts RSS Feed - CJ2a starting
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

CJ2a starting

 Post Reply Post Reply
Author
Message
Jack Williams View Drop Down
Member
Member


Joined: 10 Aug. 2014
Location: Iowa
Status: Offline
Points: 24
Post Options Post Options   Thanks (0) Thanks(0)   Quote Jack Williams Quote  Post ReplyReply Direct Link To This Post Topic: CJ2a starting
    Posted: 22 Oct. 2018 at 5:19pm
I have a 1948 CJ2a with a 6 volt system, solex carburator, and pertronix electronic ignition. I was having trouble tuning the engine to run smoothly so I tried the EI. The engine runs smooth as silk, but I have one heck of a time starting it. I am lucky if I can start it with the key. It starts and runs fine if I roll it and jump start it. I've even started it using the hand crank I made for it, but it doesn't want to start using the electric starter. I put in a new coil at the same time I installed the EI. It started for a while using the electric starter, but now nothing unless I jump start it. Does anyone have any ideas? I'm thinking the coil doesn't have enough ohms or the fuel pump is not working correctly, but when I check those two they come up fine on the limits suggested. Does the pertronix EI require more ohms?
Jack
Back to Top
athawk11 View Drop Down
Member
Member
Avatar

Joined: 18 Jan. 2012
Location: Arvada,Colorado
Status: Offline
Points: 4145
Post Options Post Options   Thanks (0) Thanks(0)   Quote athawk11 Quote  Post ReplyReply Direct Link To This Post Posted: 22 Oct. 2018 at 5:48pm
A couple things to look at:
1.Battery condition...and whether the charging system is actually charging the battery.

2. Battery cables on 6v systems are critical in two ways.  They MUST be well grounded to the frame...and the frame must be well grounded to the engine. The ground points should be cleaned and polished.  Any rust or paint will cause starting issues.  Also, the cable must be heavy duty.  Most recommend at least "0" gauge cables on 6v systems.  If light duty, you'll continue having starting issues.


1- 1946 CJ2A   
2- 1949 CJ3A
Back to Top
smfulle View Drop Down
Member
Member
Avatar
Sponsor Member

Joined: 16 Sep. 2010
Location: Ogden, Utah
Status: Offline
Points: 6123
Post Options Post Options   Thanks (0) Thanks(0)   Quote smfulle Quote  Post ReplyReply Direct Link To This Post Posted: 22 Oct. 2018 at 5:50pm
Jack,
if I recall correctly, Petronix requires the full amount of system voltage to activate the spark. (I don't have one on my 2a, but I do have a 12 volt version on my 59 Chevy). Do you have some sort of resistor in the ignition circuit that might reduce the voltage to the coil? If so, maybe the starter is drawing enough to reduce the voltage below the threshold for the Petronix. Pull starting or hand cranking doesn't pull any juice from the battery so everything can go to the coil/distributor. 
Could your battery be on it's last leg?
Stan
48 CJ2A (Grampa's Jeep)
59 Chevy 1/2 ton
Grampa's Jeep Build Thread
Back to Top
drm101 View Drop Down
Member
Member
Avatar

Joined: 12 Dec. 2012
Location: Clarkston, MI
Status: Offline
Points: 1468
Post Options Post Options   Thanks (0) Thanks(0)   Quote drm101 Quote  Post ReplyReply Direct Link To This Post Posted: 22 Oct. 2018 at 6:13pm
I'd check spark with a spark checker or pull a plug and make sure you have good spark while cranking with the starter.
Back to Top
Mark W. View Drop Down
Member
Member
Avatar
Sponsor Member

Joined: 09 Nov. 2014
Location: Silverton, OR
Status: Offline
Points: 7923
Post Options Post Options   Thanks (0) Thanks(0)   Quote Mark W. Quote  Post ReplyReply Direct Link To This Post Posted: 22 Oct. 2018 at 8:47pm
ALSO DO NOT USE SOLID CORE WIRES WITH PETRONIX
Chug A Lug
1948 2A Body Customized
1949 3A W/S
1957 CJ5 Frame Modified
Late 50's 134L 9.25"clutch T90A D18 (1.25") D44/30 flanged E-Locker D25 5.38 Since 1962
Back to Top
a4cj2a77 View Drop Down
Member
Member

Sponsor Member

Joined: 03 Sep. 2012
Location: Seal Beach Ca.
Status: Offline
Points: 566
Post Options Post Options   Thanks (0) Thanks(0)   Quote a4cj2a77 Quote  Post ReplyReply Direct Link To This Post Posted: 22 Oct. 2018 at 9:13pm
x2 on cables and battery as stated above
Phil
Back to Top
Sod Buster View Drop Down
Member
Member
Avatar

Joined: 31 July 2018
Location: Mt. Airy NC.
Status: Offline
Points: 1
Post Options Post Options   Thanks (0) Thanks(0)   Quote Sod Buster Quote  Post ReplyReply Direct Link To This Post Posted: 23 Oct. 2018 at 12:40pm
Smfulle is correct....youre not getting full power to the coil when you crank the starter. You need to run a jumper wire from the starter lug on the solenoid to the coil side of your resistor. Then when you crank it it's momentarily sending full voltage to the coil to start. I had the identical problem with a Continental F-162 when I converted it to pertronix.....Run the jumper wire and you won't even have to turn the key...just point at it and she'll be purring like a kitten
Sod Buster
Back to Top
cpt logger View Drop Down
Member
Member


Joined: 23 Sep. 2012
Location: Western Colorad
Status: Offline
Points: 3022
Post Options Post Options   Thanks (0) Thanks(0)   Quote cpt logger Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct. 2018 at 6:48pm
Just an FYI, Ohms is a measure of resistance, while Voltage is a measure of the electric pressure, or the pressure difference between two points. Voltage is what you measure across the battery terminals.

Most of the time when one is diagnosing an electrical system to see if it has power to a unit, they use the volt setting on their meter. Unless you pulled the wires off of the coil & changed your meter setting to the appropriate Ohm scale, you were measuring voltage, not Ohms.

I am not picking on you, I am trying to help you communicate better with other folks. Do not take offense.

IHTH, Cpt Logger.
Back to Top
 Post Reply Post Reply

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.06
Copyright ©2001-2022 Web Wiz Ltd.