* Cranking but not starting: This points towards a fuel delivery or spark issue, even though you've replaced parts related to those systems. Let's delve deeper:
* Fuel Delivery (despite new pump):
* Fuel filter: A clogged fuel filter could restrict fuel flow despite a new pump. This is a cheap and easy check. Replace it.
* Fuel pressure regulator: This regulates fuel pressure. A faulty regulator could prevent sufficient fuel from reaching the injectors. A pressure gauge test is needed to diagnose this.
* Fuel injectors: They might be clogged or failing, preventing fuel from entering the engine. A fuel injector diagnostic test is needed. This often requires specialized tools.
* Wiring: Check all wiring related to the fuel pump and injectors for damage, corrosion, or loose connections.
* Ignition System (despite new module):
* Distributor (if applicable): Older cars like the '94 Eighty-Eight might have a distributor. Check the cap, rotor, and ignition coil for wear or damage. Cracks in the cap or burnt contacts are common problems.
* Crankshaft Position Sensor (CKP): This sensor tells the computer the position of the crankshaft. A faulty sensor prevents proper timing of the spark.
* Cam Position Sensor (CMP): Similar to the CKP, this sensor tells the computer the position of the camshaft.
* Wiring: Again, check all wiring related to the ignition system carefully.
* Security System: A 1994 Oldsmobile might have a rudimentary anti-theft system. If the system is malfunctioning, it might prevent the car from starting.
* Other Possibilities:
* Battery: Even if the car cranks, a weak battery might not provide enough power to fully engage the starter or the fuel pump. Have it tested.
* Starter: While it's cranking, a failing starter could be the culprit. A weak starter might not provide sufficient torque to spin the engine fast enough to start.
* Engine compression: Very low compression would prevent the car from starting even with fuel and spark. This requires a compression test.
Troubleshooting Steps:
1. Check the fuel filter: This is the easiest and cheapest first step.
2. Check all the related fuses and relays for both the fuel and ignition systems.
3. Visually inspect all wiring in the fuel and ignition systems for damage.
4. Listen closely while cranking: Do you hear the fuel pump prime? (a brief whirring sound right before cranking)
5. Get a fuel pressure gauge test: This will definitively tell you if the fuel pressure is correct.
6. Use a multimeter to test the sensors (CKP, CMP) if you're comfortable with basic automotive electrical testing.
If you're not comfortable with automotive diagnostics, take the car to a mechanic. They have the tools and expertise to diagnose the problem efficiently. Giving them the information that you've already replaced the fuel pump and ignition module will save them time.
