* Incorrect Installation: The most common reason is improper installation of the new parts. This includes:
* Distributor cap and rotor alignment: They must be precisely aligned with the distributor shaft. Even a slight misalignment can cause misfiring or no spark.
* Wires connected to the wrong terminals: Double and triple check that all wires are connected to the correct terminals on the distributor cap, coil, and ICM. A single misplaced wire can disrupt the entire system.
* Distributor shaft: Ensure the distributor shaft isn't damaged or worn, causing poor timing or contact issues.
* ICM mounting and connection: The ICM needs a good ground connection. A loose or corroded ground can prevent proper operation.
* Worn or Damaged Wiring: Inspect all wiring between the components:
* Cracks or breaks in the insulation: Look for any fraying, cracks, or breaks in the wire insulation. Even small damage can lead to intermittent or no spark.
* Corrosion: Check for corrosion on the terminals and wire connectors. Clean them with a wire brush and electrical contact cleaner.
* Poor connections: Loose or poorly crimped connectors can also prevent a good electrical connection.
* Ignition Switch: A faulty ignition switch may not be providing the necessary power to the system.
* Pick-up Coil (in the distributor): While less likely after replacing the whole distributor, a failing pick-up coil inside the distributor can prevent the system from generating the necessary trigger signal for the ICM.
* Crankshaft Position Sensor (CKP sensor): (If your Bronco uses one - some 1988 models might.) This sensor tells the ICM when the engine is cranking and provides crucial timing information. A faulty sensor will result in no spark.
* Power Supply Issues: Check for proper voltage at the coil and ICM. A low voltage supply can weaken the spark or prevent it altogether.
* Ground Issues: A poor engine ground can affect the entire electrical system, including the ignition. Ensure a good connection between the engine block and the chassis.
Troubleshooting Steps:
1. Visually Inspect: Carefully inspect all wiring and connections for damage or corrosion.
2. Reconnect everything: Double-check every single connection. Disconnect and reconnect each wire and terminal to ensure a secure connection.
3. Test for spark at the coil wire: Use a spark tester to verify if you're getting spark at the coil wire when cranking the engine. If not, the problem is before the coil.
4. Check voltage at the coil and ICM: Use a multimeter to check the voltage at the coil and ICM to ensure they're receiving proper power.
5. Check for continuity: Use a multimeter to check for continuity in all wiring circuits.
6. Test the CKP sensor (if applicable): Have this tested with a multimeter or professional diagnostic tool.
7. Consult a wiring diagram: A wiring diagram for your specific year and model Bronco will be invaluable.
If you've checked all of these and still have no spark, it's time to seek professional help. A mechanic with a diagnostic tool can pinpoint the problem more efficiently. Remember safety first – disconnect the negative battery terminal before working on any electrical components.
