View Full Version : Starting (coil-spark) Problem

01-02-2017, 12:24 PM
I recently purchased a '48 CJ2A. After having the engine professionally rebuilt it will not start as it did before the rebuild. It has been converted by previous unknown owners to a 12 volt electronic ignition system and worked fine before. Now I am not getting spark out of the coil. I have replaced the coil, the coil-distributor lead, battery, battery cable, starter solenoid, spark plugs, all to no solution. The coil cable does not appear to be delivering any spark at all. I am at a loss as to what to do next as I am a complete amateur "mechanic". The old coil had absolutely no markings, no manufactures name, no model number on it. The guru at the auto parts store recommended a '78 Chevy coil as it appears to be virtually identical -at least visually- to the old coil. Can anyone tell me how to trouble shoot this coil problem? I have no idea how to test the 'primary ignition' system, whatever that is, on the coil. Any help would be greatly appreciated.

01-03-2017, 06:05 PM
Never mind. I figured it out. Turns out I had the input leads to the coil backwards..... who knew that a round coil will fit into a round bracket and rotate 360 degrees? When I removed the old coil I carefully marked all the input leads as "right" or "left" instead of "+" or "-". when I put the coil into the bracket, I had rotated the whole coil 180 degrees out of normal, so that the + and - terminals were now reversed from right or left. That plus a defective high voltage cable from the coil to the distributor managed to thoroughly confuse me. But all is now well. I learned to mark electrical leads as + or - instead of right or left. Sorry for the original problem question. dan

money pit
05-18-2017, 09:40 PM
HV was what messed with ya'.....the coil will work , just not as well, if you have + and - backwards but rule of thumb is usually negative goes to the distributer .

01-15-2018, 09:06 PM
If an engine has a coil-on-plug ignition system with no plug wires, remove one of the coils from the spark plug and insert an old spark plug, a spark plug tester or a screwdriver into the end of the coil. Ground the spark plug or plug tester to the engine, then crank the engine and look for a spark.

01-16-2018, 08:38 AM
Well, the next guy who has a problem like this might look under "Coil problems" for ideas about what to look for and this will be a learning moment for him/her.

This is a classroom for a lot of us where other people teach us and we learn from their problems.

Oh, by the way - make sure that the ground strap is welded or attached firmly to the case of the condenser... things run better that way.