1. Fuel Delivery: Even with a new fuel filter, there could still be issues:
* Fuel Pump: The fuel pump might be weak or failing to deliver sufficient fuel pressure. You need to check the fuel pressure at the fuel rail. A fuel pressure gauge is necessary for this. Low or no pressure points to a failing fuel pump.
* Clogged Fuel Injectors: Clogged injectors prevent fuel from reaching the cylinders. This requires a fuel injector cleaner or potentially cleaning or replacing the injectors.
* Fuel Pump Relay: A faulty relay could prevent power from reaching the fuel pump. Check the relay for proper operation or swap it with a known good one.
2. Ignition System (despite your efforts):
* Distributor Issues (despite replacing parts): While you replaced the rotor and cap, there might be internal issues within the distributor itself (worn points, internal wiring, etc.) or the ignition module. A failing ignition module is a common problem.
* Ignition Coil: A weak or failing ignition coil won't produce the necessary high voltage spark. Testing the coil's output with a spark tester is crucial.
* Crankshaft Position Sensor (CKP Sensor): This sensor tells the computer the engine's rotational position. A faulty CKP sensor prevents proper timing and fuel delivery, resulting in a no-start condition.
3. Computer/Sensors:
* Computer Issues (PCM/ECM): A faulty engine control module (ECM) or powertrain control module (PCM) can cause a no-start condition. This is less likely but possible.
* Other Sensors: Other sensors, like the oxygen sensor, mass airflow sensor (MAF), or throttle position sensor (TPS), could be sending incorrect data to the computer, preventing proper engine operation. Diagnosing sensor issues typically requires a scan tool.
4. Security System: Does your van have any kind of aftermarket or factory anti-theft system? A faulty system could prevent starting.
Troubleshooting Steps:
1. Check Fuel Pressure: This is the *most important* next step. Get a fuel pressure gauge and check the pressure at the fuel rail. Your owner's manual or a repair manual will tell you the correct specifications.
2. Spark Test: Use an inline spark tester to check for a strong spark at the spark plugs.
3. Listen Carefully: While cranking, listen closely to the engine. Do you hear the fuel pump prime (a whirring sound)? If not, this points to a fuel pump problem or relay issue.
4. Obtain a Diagnostic Scan Tool: An OBD-II scanner (or a scanner compatible with your van's year) will read diagnostic trouble codes (DTCs). This can help pinpoint the problem quickly.
If you're not comfortable performing these checks yourself, take it to a qualified mechanic. They'll have the tools and experience to diagnose the problem efficiently. Trying to troubleshoot further without the proper tools and knowledge could lead to further damage or wasted time and money.
