70 fury starts and immediately shuts off

70furyiii

Member
Joined
Jul 12, 2025
Messages
56
Reaction score
23
Location
Indianapolis
I’m at a loss…my 70 fury 318 will start and as soon as I release the key to run, it shuts off. I’ve replaced the ignition switch with two separate brands and still getting the same thing. It will run if I keep the key in the start position. As soon as I release to run….shuts off

I’ve bypassed the resistor under the hood and that didn’t work. Thanks in advance!
 
Last edited:
get a test light and see where you arent getting juice...bad connection in bulkhead connector?....I'd still swear its the ballast resistor by your description...maybe a coil who's output is so low it wont run thru resistor?
 
Last edited:
I’m at a loss…my 70 fury 318 will start and as soon as I release the key to run, it shuts off. I’ve replaced the ignition switch with two separate brands and still getting the same thing. It will run if I keep the key in the start position. As soon as I release to run….shuts off

I’ve bypassed the resistor under the hood and that didn’t work. Thanks in advance!
Try replacing the ballast resistor as it is needed.
 
I’m at a loss…my 70 fury 318 will start and as soon as I release the key to run, it shuts off. I’ve replaced the ignition switch with two separate brands and still getting the same thing. It will run if I keep the key in the start position. As soon as I release to run….shuts off

I’ve bypassed the resistor under the hood and that didn’t work. Thanks in advance!

I bypassed the resistor and same issue. Also purchased new one and it does same thing.


The symptom of the engine starting when the ignition key is turned to the start position, but dies when the key is released and returns to the run position is typical of a fault in the Ignition RUN circuit. Culprits can include one or more of the following:
  • bad ballast resistor
  • bad ignition switch in RUN position
  • bad wiring or connection somewhere in the Ignition RUN circuit, including:
    • bad connection in disconnect at the steering column for 1970 and later columns
    • bad connection at ignition switch
    • bad wiring from the ignition switch to the bulkhead disconnect
    • bad connection in bulkhead connector(s)
    • bad wiring to the ballast resistor from the bulkhead, typically blue for passenger cars
    • bad connection at the ballast resistor Ignition RUN side
    • loose or bad connection at the electronic control module (ECU) if equipped
Bypassing the resistor essentially rules it out as a problem, similarly for the connections at the resistor itself.

With the ballast resistor eliminated, and assuming your new ignition switch and the column connection is good, look for a wiring or connection issue in the Ignition RUN circuit, particularly at the firewall bulkhead disconnect. If you have electronic ignition, ensure the connector on the ECU is seated and secure.

If you don't already have one to trace the Ignition RUN circuit and components, the factory service manual is available as a compressed PDF zip file at MyMopar.com at the following link:

1970 Plymouth Service Manual
 
I've had a number of wires in different under hood harnesses that all look perfectly fine on the outside but the wire inside has corroded to junk. Tricky to find
 
Back
Top