Owner's Problem Description
The owner reports that their 1996 Chevrolet Corsica cranks but will not start. The vehicle does start with starting fluid and can be kept running with it, indicating a fuel delivery issue. Fuel reaches the fuel rail, leading the owner to suspect a weak fuel pump or possibly clogged or faulty injectors. They seek guidance to avoid unnecessary parts replacement.
Professional Technical Analysis
The 1996 Chevrolet Corsica is equipped with a 2.2L inline-4 engine and is likely to have between 150,000 to 200,000 miles on the odometer. The reported symptom is that the engine cranks without starting, which typically indicates a fuel delivery or ignition issue. Since the vehicle starts with starting fluid, it confirms that there is a spark, eliminating the ignition system as the primary failure point. The fuel system should be evaluated next. Fuel pressure must be verified; it should be between 35-45 PSI for proper injector operation. If fuel pressure is satisfactory, the next step is to test the injectors for proper operation and to check for electrical supply to them. A weak fuel pump can lead to inadequate pressure, while clogged injectors can restrict fuel flow. It's also essential to consider the fuel filter; a clogged filter can restrict fuel delivery to the rail, causing the symptoms described. Environmental factors such as temperature can also affect starting conditions, but with starting fluid operational, this is less likely the primary concern. A systematic approach to diagnosing the fuel system will be crucial to identifying the root cause of the no-start condition.
Possible Causes
Most common causes (ordered by frequency):
- Fuel Pump Failure: The fuel pump may be weak or failing, causing insufficient fuel pressure at the rail. Proper fuel pressure should be between 35-45 PSI; a weak pump may result in readings below this range, especially under load. Testing the pump with a fuel pressure gauge at the fuel rail can confirm this. If the pressure is low, inspect the pump's electrical connections for corrosion or damage. Common part number for replacement is AC Delco P/N 251-614. - Fuel pressure gauge readings below 35 PSI, audible pump noise during operation indicating potential failure.
- Clogged Fuel Injectors: If the injectors are clogged, they will not deliver fuel properly to the intake manifold, preventing the engine from starting. Testing each injector's resistance (typically 12-16 ohms) with a multimeter can indicate their condition. Clogged injectors might also show signs of fuel leaks or abnormal spray patterns. A common part number for replacement is AC Delco P/N 217-300. - Poor spray pattern during injector testing, resistance readings outside of normal range.
- Fuel Filter Blockage: A clogged fuel filter can restrict fuel flow to the injectors, resulting in low fuel pressure and inability to start. The fuel filter should be replaced every 30,000 miles. Use a fuel pressure gauge to verify pressure before and after the filter. Typical replacement part number is AC Delco P/N GF621. - Fuel filter appears dirty or clogged, low pressure readings after the filter.
Diagnostic Steps
Professional Diagnosis Process
Follow these systematic steps to accurately diagnose the issue. Each step builds on the previous one to ensure accurate diagnosis.
- STEP 1 - Check Fuel Pressure: Connect a fuel pressure gauge to the fuel rail test port. Turn the ignition key to the 'ON' position without cranking the engine. The pressure should read between 35-45 PSI. If the pressure is below this range, suspect the fuel pump or filter. Ensure the gauge is rated for automotive use.
- STEP 2 - Inspect Fuel Injectors: Disconnect the injector connectors and measure the resistance across each injector using a multimeter. Normal resistance should be between 12-16 ohms. If any injector shows an open circuit or significantly higher resistance, it may be faulty. Proceed to perform a flow test if injectors appear functional.
- STEP 3 - Check Electrical Connections: Inspect the fuel pump and injector electrical connectors for corrosion or damage. Use a multimeter to verify power supply to the fuel pump (should be 12V with key on) and to the injectors. A lack of voltage indicates a wiring or relay issue.
- STEP 4 - Perform Injector Flow Test: If pressure is adequate, reconnect the injectors and perform a flow test by cranking the engine while observing injector spray patterns. This will help confirm whether the injectors are delivering fuel effectively. Any uneven spray or no spray indicates a clogged injector.
