93 wrangler 4.0.....engine cranks but wont start can't get a spark...replaced ignition coil, distributor cap, plugs, wires, crankshaft position sensor. I get a CEL I've heard that means its not The ECU...another thing is every time I crank the engine I blow a 30 amp fuse that I believe is ignition/fuel.....help!

Time to meter voltage. Start with the 12V circuit. Are you getting voltage at the coil. Does the voltage fluctuate when the engine cranks? If yes to both check the high voltage circuit. Start with the coil then the distributor then each plug. You should be able to find where the spark is failing.

If theres no spark from the spark plugs then you would have to replace them?

the ignition module probly bad-replaces points and located in distributer area--batt must also read 12.6v and alternator must be healthy--fuses may not all be good--take a light tester to um--make sure inline safety fuse on the batt line is workn

If your engine cranks normally but will not start because it has no spark, or it stalls and won't restart because it has no spark, the problem may be due to any of the following:

A bad pickup inside the distributor (on engines that have a distributor), a stripped distributor drive gear (common problem with plastic distributor drive gears), broken, loose or corroded wires from the pickup to the ignition module orPCM.

A bad crankshaft position (CKP) sensor (on engines that do not have a distributor), or broken, loose or corroded wires from the sensor to the PCM.

A bad ignition module (on engines that have a distributor or use an ignition module separate from the PCM)

A bad ignition coil (on engines that have a distributor and a single coil)

A bad rotor or distributor cap (cracks or carbon tracks that are allowing the spark to short to ground)

Faulty ignition switch.

Pull off the coil ignition cable at the distributor and check for spark coming out of coil when cranking engine over. Use a heavy rag or glove to hold the wire 1/4 inch from a metal ground. Should see a strong blue spark when cranking to verify ignition is good. If no spark, check for battery voltage to coil on the coil primary. If you have current to the coil, suspect a bad coil, ignition module, crank position sensor, or cam position sensor, or pcm. The coil, ignition module, and sensors can be tested before replacing.

Test the ignition system output, ignition systems can vary in configuration but operate on the same principal. Ignition systems can consist of a coil, pick up coil, crank angle sensor, cam angle sensor, spark plugs, spark plug wires, distributor cap, ignition rotor and a distributor and any variations of these components. An ignition coil is a voltage stepper coil that transforms a low voltage (12 volts) signal into tens of thousands of volts needed to jump the gap of the spark plug.

This coil is activated by an ignition module triggered by using the camshaft/crankshaft angle sensor; timing is adjusted by the PCM (computer).This primary electrical signal is generated by the PCM which calculates spark timing by using a variety of sensors including coolant temperature, mass air flow, and oxygen sensors. Go to 2carpros.com for a video on how to check this using a 12v light tool. On the engine repair section search, type, "engine cranks but will not start." If my answer helpe you, please leve good feedback. thanks

Hi, Ok you have confirmed that it's not a fuel problem. You need to check for spark. Pull the coil wire off of the coil(secondary lead-looks like a spark plug wire) Have some one crank it over and listen for a popping sound. IF yes, spark is at the coil, that means all ignition sensors are working. Next check for spark at ends of wires after cap. IF no replace cap and rotor. IF yes remove a couple spark plugs and check for fouling(wet, fuel etc...) IF yes replace or clean plugs and retest for starting. IF no spark is present at coil you need to scan computer and watch for rpm signal. IF no rpm signal, replace crankshaft sensor with OEM delco part. BIGGEST problem with these engines is Cap and Rotor burn out.

Depending on which engine your car is equipped with; the following components could be at fault.

Crankshaft Position Sensor
Camshaft Position Sensor
ECM (Engine Control Module)
Distributor Cap or Rotor
Fouled Spark Plugs
Bad Plug Wires

If they haven't been replaced in the last 30K miles, I suggest you check and /or replace the the plugs and wires first.

If your engine is equipped with a distributor, check and/or replace the distributor cap and rotor if it hasn't been replaced in the last 30k miles.

If your engine is equipped with crank or cam sensors have them tested.

Check your Crankshaft position sensor

ENGINE CRANKS BUT WILL NOT START
When the engine cranks normally but won't start, you need to check ignition, fuel and"http://www.aa1car.com/library/compression.htm". Ignition is easy enough to check with a spark tester or by positioning a plug wire near a good ground. No spark? The most likely causes would be a failed ignition module, distributor pickup or "http://www.aa1car.com/library/crank_sensors.htm".
A tool such as an Ignition System Simulator can speed the diagnosis by quickly telling you if the ignition module and coil are capable of producing a spark with a simulated timing input signal. If the simulated signal generates a spark, the problem is a bad distributor pickup or crankshaft position sensor. No spark would point to a bad module or coil. Measuring ignition coil primary and secondary resistance can rule out that component as the culprit.
Module problems as well as pickup problems are often caused by loose, broken or corroded wiring terminals and connectors. Older HEI ignition modules are notorious for this. If you are working on a distributorless ignition system with a Hall effect crankshaft position sensor, check the sensor's reference voltage (VRef) and ground. The sensor must have 5 volts or it will remain permanently off and not generate a crank signal (which should set a fault code). Measure VRef between the sensor power supply wire and ground (use the engine block for a ground, not the sensor ground circuit wire). Don't see 5 volts? Then check the sensor wiring harness for loose or corroded connectors. A poor ground connection will have the same effect on the sensor operation as a bad VRef supply. Measure the voltage drop between the sensor ground wire and the engine block. More than a 0.1 voltage drop indicates a bad ground connection. Check the sensor mounting and wiring harness.
If a Hall effect crank sensor has power and ground, the next thing to check would be its output. With nothing in the sensor window, the sensor should be "on" and read 5 volts (VRef). Measure the sensor D.C. output voltage between the sensor signal output wire and ground (use the engine block again, not the ground wire). When the engine is cranked, the sensor output should drop to zero every time the shutter blade, notch, magnetic button or gear tooth passes through the sensor. No change in voltage would indicate a bad sensor that needs to be replaced.
If the primary side of the ignition system seems to be producing a trigger signal for the coil but the voltage is not reaching the plugs, a visual inspection of the coil tower, distributor cap, rotor and plug wires should be made to identify any defects that might be preventing the spark from reaching its intended destination.----
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