ASE G1 Auto Maintenance and Light RepairElectrical/Electronic SystemsMedium
A technician is diagnosing a vehicle where the engine cranks normally but fails to start. The fuel pump can be heard operating when the ignition is turned to the 'ON' position, and there is spark at the spark plugs. The 'CHECK ENGINE' light is not illuminated. What is the most likely cause of this no-start condition?
- AA clogged catalytic converter.
- BAn open in the fuel injector circuit.
- CA discharged battery.
- DA faulty crankshaft position sensor.
Show answer & explanationAnswer & explanation
Correct answer: B. An open in the fuel injector circuit.
Given that the engine cranks, there is spark, and the fuel pump operates, the issue is likely a lack of fuel delivery to the cylinders. An open in the fuel injector circuit would prevent fuel from being injected, causing a no-start condition despite other systems functioning.
Why the other options are wrong
- A. A clogged catalytic converter typically causes a vehicle to start but run poorly, or stall after starting, not a no-start with normal cranking and spark.
- C. A discharged battery would prevent the engine from cranking normally.
- D. A faulty crankshaft position sensor would typically prevent spark or fuel pump operation, neither of which is indicated here.
No-Start Diagnosis
Diagnosing a vehicle that cranks but does not start requires checking the presence of fuel, spark, and compression. If all three are present, the timing or quantity may be incorrect.
- Engine cranks normally.
- Spark is present.
- Fuel pump operates.
Memory trick: Crank, Spark, Fuel – The trifecta of starting success.