* Crankshaft Position Sensor (CKP sensor): This sensor tells the computer the engine's rotational position, crucial for timing the spark and fuel injection. A faulty CKP sensor will prevent the computer from sending signals to both the coil and injectors. This is a very common cause of "no spark, no fuel" situations.
* Cam Position Sensor (CMP sensor): Similar to the CKP sensor, but for camshaft position. Some systems rely on this sensor as well for proper timing.
* Ignition Control Module (ICM): This module receives signals from the computer and controls the ignition coil. A faulty ICM will result in no spark.
* Powertrain Control Module (PCM) / ECM (Engine Control Module): The "brain" of the system. A faulty PCM/ECM can cause a wide range of problems, including no spark and no fuel. This is less likely than a sensor failure, but possible.
* Ignition Switch: A malfunctioning ignition switch might not send power to the necessary circuits, including the PCM/ECM and related relays.
* Fuses and Relays: Check all fuses related to the ignition system, fuel injectors, and the PCM/ECM. Even though it's less likely a single relay controls both, check *all* relevant relays. Look for blown fuses or relays that are stuck.
* Wiring: A broken or corroded wire in the main power supply or control circuits can interrupt power to the coil and injectors. Check for loose connections and damaged wires, particularly in areas prone to vibration or moisture.
* Ignition Coil: While less likely in this scenario (since you have *no* spark), a completely dead coil is possible.
Troubleshooting Steps:
1. Check the basics: Start with the simplest checks: fuses, relay operation (check for proper clicking when the key is turned), and obvious visual inspection of wiring for damage.
2. Test for power and ground: Use a multimeter to check for power and ground at the coil and injectors. This will help you isolate if the problem is before or after the components themselves.
3. Check the CKP and CMP sensors: These are prime suspects. They can often be tested with a multimeter, though the specifics depend on your van's year and engine. Consult a repair manual for your specific model.
4. Consult a repair manual: A factory service manual or a reputable online resource specific to your Chevy van's year and model will have wiring diagrams, diagnostic trouble codes (DTCs), and troubleshooting procedures. This is absolutely essential for proper diagnosis.
5. Read diagnostic trouble codes (DTCs): If your van has a diagnostic port (OBD-I or OBD-II), try using a code reader to see if any error codes are stored in the PCM/ECM. These codes can give you valuable clues.
It's crucial to systematically check these areas to pinpoint the root cause. Jumping to conclusions without proper testing might lead to unnecessary part replacements. A repair manual and/or a code reader are vital tools for this process.
