No Spark with Electronic Ignition Conversion

[Doug D]

Hi,

I'm working on a '70 Cuda 440 with the electronic ignition conversion which was installed a few years ago. This is the version with the 4120505 orange controller. I have no spark. Does anyone have a troubleshooting guide for this system? Or, lacking that, what resistance value should I see at the distributor pick up?

Thanks,
Doug

[MEK-Dangerfield]

Ballast resistor should be 1.2 Ohms, if you have the single resistor type. The pick-up coil resistance is anywhere from 150 Ohms to 900 Ohms. With your key in the "on" position, see what voltage you have on the "+" side of the ignition coil.

[Chryco Psycho]

basically test the coil , wiring for correct voltage , ballast , & dist pick up , if all test good the ECU is bad .
the dist can be intermittent , I have seen them work until they heat up then they will shut down , if you have continuity it should be working 

[Doug D]

Thanks, guys.

Yesterday I pretty well narrowed it down to the pickup coil and now that I know the acceptable resistance range I can verify.

I'll post back if I'm still jammed up.

Thanks,
DD

[Doug D]

The car is running now. I replaced the coil.

The coil it had (from MSD...can't remember the exact model) had .9 ohm primary resistance and 7k ohm secondary resistance....which by right sounds "OK" (to me, at least) but I replaced it as a guess when everything else checked OK. The engine fired right up.  I used a brand-x replacement coil from the local auto parts store for the time being.

A bit of research suggests I need a coil with about 1.5 ohm primary resistance. Some say to use a 2495531 or 2444241 Mopar coil.

Is there a particular coil that I should be using with the orange 4120505 box? What are you guys using?

Thanks
Doug

[Chryco Psycho]

I use the MSD vibration coil or the pertronic high output coils