* Ignition Control Module (ICM): This is a common failure point in GM vehicles of that era. The ICM receives signals from various sensors and controls the ignition system. A faulty ICM will prevent the coil from firing.
* Ignition Coil: While less likely if you're getting *no* spark at all (a failing coil usually gives a weak or intermittent spark), it's still possible a coil is completely dead. Testing is required.
* Crankshaft Position Sensor (CKP Sensor): Some GM engines of this vintage use a CKP sensor to tell the ICM when to fire the coil. A faulty sensor won't provide the necessary timing signal.
* Wiring Issues: Even with new wires, there could be a break, short, or poor connection somewhere in the wiring harness between the ignition switch, ICM, distributor, and coil. A thorough visual inspection is needed, looking for damaged insulation, corrosion, or loose connections. Pay particular attention to grounds.
* Distributor Issues (Beyond Cap and Rotor): While you replaced the cap and rotor, the distributor itself could be faulty. Things like internal wear, a cracked shaft, or problems with the advance mechanism can disrupt spark delivery.
* Ignition Switch: A faulty ignition switch might not be sending power to the necessary components.
* Fuse/Circuit Breaker: Check the fuses and circuit breakers related to the ignition system.
How to Proceed:
1. Visual Inspection: Carefully examine all wiring related to the ignition system. Look for any damage, corrosion, or loose connections.
2. Testing: You'll need a multimeter or a specialized automotive testing tool to check the voltage and continuity of the ICM, coil, and CKP sensor (if applicable). There are specific tests for each component; you'll likely find diagrams and procedures in a Haynes or Chilton repair manual for your specific van.
3. Professional Diagnosis: If you're not comfortable testing electrical components, taking the van to a qualified mechanic is advisable. They have the tools and expertise to quickly diagnose the problem. Throwing parts at it without testing is expensive and inefficient.
Don't replace the pickup coil until you've ruled out the other possibilities. It's relatively inexpensive, but replacing it without first verifying it's faulty is a waste of time and money.
