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1973 Challenger no spark issues

8408 Views 2 Replies 3 Participants Last post by  qiutong
Hello all. I have a 73 Challenger with a 318. This is my first rebuild and I'm a bit stuck. I completely tore down the engine, replacing piston rings, bearings, timing gears/chain, cam, lifters, pushrods, heads, intake , carb, etc,etc. For the most part, everything on the engine is new. The engine has ran and driven previously (before the tear-down and part swaps) I've re-assembled everything and the motor is back in the Challenger with no luck of getting it started. My main problem now is no spark. To be even more clear...when I turn the key, it seems like the only thing working is the starter motor. The starter is working, the pulleys are moving, rocker arms are moving (verified with valve cover off) but there is absolutely no inclination of compression or combustion whatsoever. I know that seems vague...

Like I said, no spark seems to be the main issue. I checked for spark at the spark plugs and nothing. Checked at the coil and no spark. I have battery voltage at the positive terminal of the coil when key is on and about 9-10 volts during engine crank. I took the distro cap off during crank to make sure rotor was spinning and it is. Voltage is there at the coil...its just not leaving the coil.

Here's my ignition set-up. I have an MSD ready to run distributor and an MSD blaster 3 coil. The coil is brand new as well as the spark plug wires. Originally thought those two couldv'e been the problem but obviously not.

I'm completely stumped and would greatly appreciate any help. Thanks,
1 - 3 of 3 Posts

· Premium Member
6,106 Posts
Welcome to the forum. It sounds like you are actually having a wiring problem. Do you have both a wiring diagram for the Challenger itself and the replacement wiring for the coil itself? You should have a ballast resistor mounted near the distributor, which is needed for the electronic ignition itself, without it the hall effect will burn out. The ballast resistor is white, rectangular, and you may have the four plug, two on each side, which reduces the voltage to the hall effect distributor. If you have power from the coil. From there, check the wiring with the wiring diagram first, then the rewire for the MSD setup. You can find the wiring diagram online, actually an easy one to find. Start with that.

· Registered
4 Posts
Hi Josh,

Welcome to the Allpar forums, I'm pretty new here also, hopefully I can help you out in some way. I found the installation instructions for the Mopar version of the MSD ready-to-run distributor here; http://static.summit...88_frm30249.pdf and the hook up looks pretty straight forward. The only electrical connections with the car (other than the tach) are a switched 12 volts that provides 12 volts with the key in the "on" position and also in the "start" position and is dead in the "off" position. Based on your post, it sounds like you have that. The 9-10 volts while cranking is normal since the starter draws so much power, but it never hurts to make sure your battery is at full charge whenever you're troubleshooting electrical problems. The second connection with the car is the ground. I would suggest that you eliminate your ballast resistor if you have one. They were used to reduce the voltage going to the original ignition system, but the MSD indicates that it needs a full 12 volts to work properly.

So, given what we know, I'd make sure that the ground connection is good. Where have you grounded it? If you have it grounded to the engine in some way, make sure that the engine is also grounded. Given that you've just rebuilt and re-installed the engine make sure that the engine grounding strap wasn't forgotten and is making a good connection with the engine block and the car body. Somehow, either through the engine/car body combination, or directly, the distributor ground connection has to be connected to the negative side side of the battery.

If all of the electrical connections are good and proper, I'd suspect that something within the distributor is malfunctioning. If that's the case, I'd give MSD tech support a call at: 1-888-673-7859 and let them have a shot at it.

Hope this helps.

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