Malfunction in the throttle position sensor

A malfunction in the throttle position sensor can give the ECU the wrong information about the amount of air entering the engine. The can cause the ECU to deliver the wrong amount of fuel, and either flood or starve the engine, causing a stall.

Table of Contents

• 1. Symptoms
  • 1.1 Engine Stalls
  • 1.2 Engine Backfires

Symptoms

Engine Stalls

If the throttle position sensor is telling the ECU that the throttle valve is closed(or more closed) when is open, the ECU may reduce the amount of fuel delivered to the intake manifold. The fuel/air ratio will drop, and the engine will not have enough power to maintain its momentum.

Engine Backfires

If the throttle position sensor is telling the ECU that the throttle is open when it is closed(or more closed), the amount of fuel deliver to the engine will increase. This can cause fuel to overwhelm the engine and flood it, or it can add a small amount of extra fuel to each piston stroke.

The fuel may not burn up entirely in the combustion chamber. Some may escape into the exhaust manifold where it is ignited. This will cause a backfire.