My jeep grand cherokee 1993 4.0 liter straight six. Keeps burning the coils. I have replaced the crank sensor and new plugs and plugwires.I replaced the ground cable. Any ideas?

Check the input voltage to coil while starting the engine and once the engine starts. While starting you should see battery voltage. Once the engine starts, the voltage should drop to 8-9 volts. If you don’t see this voltage drop once the engine starts, the ignition module is failing to switch to the run mode once the engine is running.


I do not have a ignition module in the dist. Only a cam sensor. Mine has a PCM