1. The Basics (Always Start Here):
* Battery: Test the battery voltage. A weak battery can cause intermittent or no spark and affect the fuel pump. Check the battery terminals for corrosion.
* Fuses and Relays: Check all fuses and relays related to the ignition system and fuel pump. Your owner's manual should have a fuse box diagram. Pay close attention to the fuel pump relay and any ignition-related fuses.
* Grounds: Poor grounds can prevent the system from working properly. Check all ground straps connecting the engine to the chassis. Clean any corrosion.
2. No Spark:
* Ignition Coil: A bad ignition coil is a common cause of no spark. Test the coil's primary and secondary resistance using a multimeter (consult your vehicle's specifications for correct resistance values). A visual inspection for cracks or damage is also recommended.
* Ignition Control Module (ICM): This module controls the ignition coil. A faulty ICM will prevent spark. These are less easily tested at home and often require professional diagnostic tools.
* Distributor (if equipped): Check the distributor cap and rotor for cracks, corrosion, or worn contacts. Replace if necessary. Inspect the distributor shaft for wear.
* Crankshaft Position Sensor (CKP): This sensor tells the computer the engine's rotation. A faulty CKP will prevent the computer from sending the signal to fire the coil.
* Camshaft Position Sensor (CMP): Similar to the CKP, this sensor is critical for proper ignition timing. A fault here can also prevent spark.
* Ignition Switch: A faulty ignition switch can prevent power from reaching the ignition system.
3. No Fuel:
* Fuel Pump Relay: As mentioned earlier, check this relay. You can often swap it with a similar relay (check the amperage rating!) to see if it's the problem.
* Fuel Pump: Listen carefully near the fuel tank while someone cranks the engine. You should hear a whirring sound from the fuel pump for a few seconds when the ignition is turned on. If you hear nothing, the pump might be faulty or not receiving power. A pressure test is recommended to confirm fuel pump operation.
* Fuel Pump Fuse: Check the fuse related to the fuel pump.
* Fuel Filter: A clogged fuel filter will restrict fuel flow. Replace it if it's dirty or damaged.
* Fuel Pressure Regulator: A faulty regulator can cause low fuel pressure or leaks.
* In-Tank Fuel Pump: This is a common problem. Accessing it may involve dropping the fuel tank.
4. Diagnostic Tools:
* Multimeter: Essential for testing voltages, resistances, and continuity.
* OBD-I Scanner (for this year vehicle): A scanner can read diagnostic trouble codes (DTCs) from the vehicle's computer, which can pinpoint the problem. OBD-I is more primitive than later systems, requiring a scanner specific to that year vehicle.
Troubleshooting Steps:
1. Start with the basics (battery, fuses, grounds).
2. Check for spark (if none, focus on ignition components).
3. Check for fuel (if none, focus on fuel pump and related components).
4. Use a multimeter to test components (voltages, resistances).
5. If possible, use an OBD-I scanner to read DTCs.
If you're not comfortable working on your vehicle's electrical system, it's best to take it to a qualified mechanic for diagnosis and repair. Improperly working with automotive electrical systems can lead to injury or further damage.
