starting problems

[mcelroymopar]

I have a 1974 plymouth duster and lately have been having a long time problem with starting the car. For a few months i could only start the car by bypassing the starter relay, and it worked just fine. Since then me and my dad have been replacing the wiring harness. Now that were almost done with all the wiring the problem has only gotten worse. The car will only start when I am holding the key in the crank position and we still have to bypass the starter relay. As soon as i release the key from the cranking position, the car shuts off. We replaced the ignition switch already and that didnt help. Any suggestions???? im in need of some mopar expertise.ale:

 

[Bad Sport]

As far as bypassing the relay, I don't know. But if the car starts and will stay running as long as you hold the key and quits when you release it, sounds like a bad ballast resistor. I had a Barracuda do that once, had me puzzled for a minute.

 

[mcelroymopar]

We replaced the ballast resistor since the last one broke apart. Thank you for your input, anything is always appreciated!

 

[nm9stheham]

If the ballast is new, then the issue is most likely that the wire to the ballast resistor from the ignition switch is no good; that wire was originally blue. Use a voltmeter and turn the ignition switch to RUN and measure the wire's voltage that feeds to the ballast; it should be close to battery voltage. It will most likely not be so since you have the RUN problem. At that point, it needs to be traced back to the ignition to find the problem in that wire.

As for the problem with the starter relay, is this car an automatic or manual trans car? Each has a 'safety switch' that has to be grounded before the start circuit can activate. The auot trans has a neutral safety switch that is combined with the back up light switch on the side of the auto trans. The mnaual trans cars use a clutch switch up under the dash. To see if this is the problem, use a short wire jumper to ground the connection on the starter relay that goes to the green wire on a manual car, or to the brown-yellow wire that goes down towards the trannie in an auto car. Then try to start the car; if so, then it the safety switch or its wiring is the porblem. If not, then the 12V to activate the relay coming from then ignition switch is the problem.