Before jumping to the SMEC:
* Crankshaft Position Sensor (CKP): This sensor tells the SMEC the position of the crankshaft, crucial for timing the spark. A faulty CKP sensor will prevent the SMEC from sending a signal to fire the coils. This is a very common cause of no-spark issues.
* Cam Position Sensor (CMP): Similar to the CKP, this sensor tells the SMEC the position of the camshaft. Some 318s use this, especially if equipped with multi-port fuel injection. A faulty CMP will also prevent spark.
* Ignition Control Module (ICM): While integrated into the SMEC on some vehicles, some 1995 Dodge vans might have a separate ICM. This module receives signals from the SMEC and controls the ignition coils. A failed ICM would result in no spark. (Check your wiring diagram to confirm if you have a separate ICM.)
* Ignition Coil(s): A faulty coil or coils will prevent spark. Testing each coil individually is necessary to rule this out.
* Wiring: Check all wiring connections between the SMEC, CKP/CMP, ICM (if applicable), and ignition coils. Corrosion, broken wires, or loose connections are common culprits.
* Fuses and Relays: Make sure all fuses and relays related to the ignition system are good.
How to troubleshoot:
1. Check for power at the coil: With the key on, you should have power to the coil(s). If not, trace back the wiring to identify the break in the circuit.
2. Check the CKP and CMP (if applicable) sensors: These can often be tested with a multimeter; consult a repair manual for your specific vehicle to find the testing procedure.
3. Visually inspect all wiring: Look for any obvious damage, corrosion, or loose connections.
4. Check fuses and relays.
5. If all else fails, test the SMEC: This requires a specialized scan tool or knowledge of the SMEC's internal circuitry. It's usually the last resort and often best left to a qualified mechanic due to the complexity and cost of the SMEC itself.
In short: While a faulty SMEC *could* be the problem, it's more likely a simpler, cheaper component is failing first. Systematic troubleshooting is key to identifying the root cause. Consult a repair manual specific to your 1995 Dodge van 318 V8 for detailed wiring diagrams and testing procedures.
