electric problems

[roelbest]

I am getting ready to start the RR after the rebuild, but have a spark problem. The motor swings fine, fuel gets to the carb, but no spark on the plugs.
Checked the new coil, while turning the motor it does not spark, except for a small spark as I stop turning the motor. Next step was to check the ballast resistor, it is also new. By touching the terminal with a tester, the upper right shows a very weak glow, the other 3 terminal lights up more bright. Changed the resistor and coil with the old ones, no difference.
Is the next step to change the electronic ignition unit? I am still using the original one, as it is '72.
I have made sure that the earth straps are good.
All the wiring looms are new, plugleads, coil etc all new.
I'll appreciate any input, I am in a bit of a remote spot on this island to get help with a car.
thanks

[MPerry]

You have electronic ignition or points? Factory setup should be points. http://www.mymopar.com/downloads/1972/72SatelliteA.JPG

[Moparlar]

You have electronic ignition or points? Factory setup should be points. http://www.mymopar.com/downloads/1972/72SatelliteA.JPG

72 Roadrunners were Electronic Ignition from the factory

[MPerry]

Hmmm guess I'm looking at a bad diagram then. I was originally looking to see if it was a 4 or 5 pin unit and saw only one wire on distributor.

[roelbest]

' 72 440, electronic ignition
I guess I have to work backwards from the plugs towards the ignition. Will get a new 'orange box' next week as the next step....
Could it be that the earth is not good enough, although I have put an extra strap from engine to bulkhead just to make sure
(now off to bed, it is late here-)

[GTXS]

Maybe the ballast resistor? Cheaper then a new box and if thats not the problem you have an extra one just in case.

[JimT1971RR]

I ran into the same problem with my 71. I converted it to electronic, new coil, ballast, plugs and wires but was getting no spark. Ultimately, I found that the problem was that I had the tachometer lead attached to the negative side of the coil, but I don't have a tach. Once I removed that wire from the coil, it immediately fired. I hope this helps.
Jim

[roelbest]

thanks guys, I'll look into this tonite!
I have a tach wire, sure it fits on the coil where it says 'distributor'

[gcoupe72]

If you've got a service manual. Double check the wire color, I think it's dark blue.
Find the wire at the five wire plug on the control unit that should be "hot" when the key is in the run position.
You should have battery voltage here when the key is in the run position.
If you don't, this is a problem!
You can jump this wire to the battery, and the car should start. If it won;t crank over, then jump the starter relay with a screw driver, or remote start switch.
Now, the neutral switch if auto., or the clutch pedal switch will keep this from working if they are at fault.
You can add a ground wire to the relay to bypass them. Just make sure you're not in gear!
Let us know what works.

[roelbest]

Thanks gccoupe, the wire is blue, have checked. Unforunately have to go away for a few days due to something that came up at work. Only back now next week, but I;ll defenitely let you guys know. I have a new electronic box on the loan as well to try when I'm back

[roelbest]

Ok, after a few weeks I am back on the car.
Still no spark at either plugs or coil.
orange box has 3 wires that show 12 volt when ignition is in on position. I have also put a new control unit on, no difference.
Motor tuns easy, but has no spark.
A stupid question maybe: if I test the coil, it shows only 6 volt, should that not be 12 volt?
The 4 plug at the orange box shows 12 volt on 3 of the prongs, from there it goes to the coil, and only read 6 volt at the coil.Could this be a problem?
Thanks for any help, i am a bit lost at the moment