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I have only a spark from the coil when the key is turned to the start position. As the engine turns over, no more spark. For this problem I have replaced the ballast resistor and the control box.
Any ideas??
Sounds like the pickup coil in the distributor or it's circuit to the ignition module,(control box), is your problem. If you've got an ohm meter you can check it by connecting the ohm meter leads to the two, disconnected, wires attached to it. Should be 150-900 ohms resistance.
On a Dodge this symtom has almost always been the ballast resistor problem or wire from there to coil. To test put 12v to plus side of coil and see if that cures it, if it does go back to ballast and recheck it and the wiring. The engine won't shut off until the 12v is removed.
In the ChryCo. ignition, the resister feed to the coil, (the .5 ohm side), is bypassed during cranking, if that side fails, the engine will start, but dies on the key being released to return to "run". Sometimes the engine will continue to run,but dies on acceleration due to the coil now being fed thru the 5 ohm side of the dual ballast resister which also feeds the module. It wasn't designed this way, but it will do it. The lesser current to the coil results in a very weak secondary voltage which can't jump the plug gap when higher cylinder pressures occur on increased theottle opening.
Remember, the original post said coil would fire when key on-key off, this was breaking the primary circuit and "firing" the ignition module, so primary circuit and feed to module is OK, what's not happening is primary interrupt, the function of the pickup coil. An easy test for the pickup coil is to remove distributor cap, crank engine over until no reluctor tooth is in front of the pickup coil, turn the key to "run", pull the coil wire from the center of the distributor cap,hold the end of the coil wire about a 1/4" away from a ground, ( clean metal part of engine), and pass the blade of a small screwdriver back and forth in front of and close to the metal segment of the pickup coil, a spark should jump from the coil wire to ground each time you do this. If you get the spark, then pickup coil or it's wiring to ignition module is bad, rest of system is good. |
RV and bus conversion info since 1996.
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