Some Fuel Problems Are Electrical Problems
Sometimes, when an engine is not performing well or fails to start, it's common to attribute the problem to the quality of the gasoline or a faulty fuel pump.
However, this perspective is incorrect. In certain cases, what may seem like a fuel-related issue is actually an electrical problem involving either the ignition system or the power supply to the fuel pump. Here are some suggestions for diagnosing such problems:
Check for spark: Use an inline spark plug tester connected to one of the spark plug leads. If a spark is produced, it indicates that the ignition system is functioning correctly. Keep in mind that certain faults, like a faulty condenser, may only become apparent under engine load.
Verify correct timing: For older engines using a distributor system, timing can be easily checked. Direct a timing light at the crank pulley mark and trigger it with an inductive pickup clipped to the number 1 spark plug wire. Check the advance angle, which is typically around 12° at idle. Late-model vehicles with computer-controlled ignition systems do not allow timing adjustments, but a persistent fault may trigger the Check Engine light.
Confirm fuel pump operation: Modern fuel-injected engines feature an electric fuel pump typically located inside the fuel tank. If the vehicle has been idle for some time, you should hear the pump running when you first turn the key. If there is no sound, the fuel pump needs to be examined.
Consider the inertia switch: Ford vehicles have an inertia switch in the fuel delivery system that shuts off the fuel supply in the event of a collision. However, even a minor impact can trigger it, so this should be checked as a first step.
Ensure fuel reaches the engine: For carbureted engines, fuel injection can be observed visually by removing the air filter and quickly blipping the throttle. Fuel injection systems require more complex testing. Connect a pressure gauge to the fuel rail (most manufacturers provide suitable fittings) to verify sufficient fuel pressure. The acceptable pressure range can be found in the vehicle's manual.
Check for fuel blockage: If there is no fuel supply or if the pressure is too low, inspect the fuel filter for any obstructions. Locate the filter, remove it, and clean it if necessary.
Instead of immediately suspecting the fuel pump when an engine runs poorly, it is important to prioritize electrical components as the potential root cause.
