Engine is running lean

When the engine is not receiving enough fuel in the fuel/air mixture, it is said to be running lean. This usually results from a defect in the fuel delivery system, resulting in a loss of engine power.

Table of Contents

• 1. Symptoms
  • 1.1 Engine Power Reduced
  • 1.2 Engine Stalls
• 2. Causes
  • 2.1 Defective Fuel Injectors
  • 2.2 Defective Fuel Pump

Symptoms

Engine Power Reduced

A reduction in engine power can result from a lean fuel mixture. The power created by the ignition of the fuel will be reduced, causing the engine to struggle or be weaker than normal.

Engine Stalls

A lean fuel mixture may not produce enough power to keep the engine running. As the cylinders fire, the necessary power to maintain the momentum of the crankshaft may not be reached. This will cause the engine to stall. It may be more apparent during acceleration as more air enters the engine, but not enough fuel does.

Causes

Defective Fuel Injectors

Defective fuel injectors may deliver the wrong amount of fuel to the intake manifold.

Defective Fuel Pump

A defective fuel pump may not be able to draw the proper amount of fuel from the tank, resulting in insufficient fuel reaching the engine.