Could any one tell me if the 74 interlock system also disables ignition? I have the starter working after a bypass but now have no spark.

Any linkage between these two?

Thanks,

Dean

Yes, it does.

Thanks Steve, I thought so but not sure how to proceed from here.

I've eliminated the start button and firewall relay.

Any wisdom to share as far as jumping these to get my spark back?

I have the starter working by tapping into power off the firewall relay.

Any help appreciated.

Dean

Edited April 1, 201410 yr by idoxlr8

I have to take that back. It doesn't. I have to stop answering questions when I don't get much sleep the night before. If the interlock relay affected the running of the car, the emergency button wouldn't work.

Let's go back. You've made some electrical changes. Please identify all of the modifications you've made to the wiring, whether or not you think it will affect the running of the car.

Have you done any basic testing?

Do you have 12 VDC to the ballast resistor with the key in the ON position?

I do have 12 volts to the ballast. The only wiring changes were to the interlock system. Have a new coil as well.

I'm wondering if the 40 year old transistor box is suspect but the car ran fine before I pulled it down three years ago.

Are you sure all of the wiring to the ignition box and tachometer are correct and good? Either one could cause it not to run.

You could wire in an HEI as a temporary to test to see if it's the ignition box. Note: Disconnect the ignition box while running that test. An HEI is a relatively cheap test. You can get them for $12 plus shipping from Rockauto.

I'm going to do some more diagnostics next weekend and I'll let you know if I find something.

Thanks again.

Dean

Update.

Ignition box had packed it in.

Bought a Crane 3000 box with optical trigger, new coil, ditched the ballast and it now runs and starts great.

Dean