Car Fuel Cut-Out: Understanding The Warning Signs

Fuel cut is a removal of the injector firing signal from the ECU, meaning that the engine computer doesn't put fuel in the engine. This is caused by the ECU seeing more air entering the engine than it was originally programmed to use.

Fuel cut is a removal of the injector firing signal from the ECU

Despite the rumors of fuel cut being caused by too low of fuel pressure, too small of injectors, high flowing exhaust, high flowing intake, or large turbos, fuel cut is not directly caused by any of these. Fuel cut is actually caused by the ECU seeing more air entering the engine than it was originally programmed to use. This likely corresponds with an injector duty cycle which is unsafe or unattainable.

The feed flow of fuel is cut off by means of electrical shut-off valves in the event of failure of the system, eg: because of an accident. Thus the risk of fire in the car is avoided.

The engine is an air pump, even if there's no fuel, if the engine is connected to the wheels and the wheels are turning, the engine keeps running and keeps pumping air. You still hear it running because it's still actively taking in air and pumping it through the engine and out the exhaust.

From a controls perspective, if your engine RPM's are above idle by some amount and your throttle pedal position (not the actual throttle position, the pedal) is below some threshold (say 1%) then the engine will cut fuel.

Engine cuts fuel if it sees more air entering than it was programmed to use

The ECU (engine computer) cuts the fuel if it sees more air entering the engine than it was originally programmed to use. This is likely to correspond with an injector duty cycle which is unsafe or unattainable.

The feed flow of fuel is cut off by means of electrical shut-off valves in the event of system failure, eg: because of an accident. Thus the risk of fire in the car is avoided.

The engine is an air pump, even if there's no fuel, if the engine is connected to the wheels and the wheels are turning, the engine keeps running and keeps pumping air. You still hear it running because it's still actively taking in air and pumping it through the engine and out the exhaust.

The ECU cuts the fuel if it sees more air entering the engine than it was originally programmed to use. This likely corresponds with an injector duty cycle which is unsafe or unattainable.

The feed flow of fuel is cut off by means of electrical shut-off valves in the event of system failure, eg: because of an accident. Thus the risk of fire in the car is avoided.

Fuel cut-off is caused by electrical shut-off valves in the event of system failure

The feed flow of fuel is cut off by means of electrical shut-off valves in the event of a system failure. This is to avoid the risk of fire in the car and is caused by the ECU seeing more air entering the engine than it was originally programmed to use. This is likely to correspond with an injector duty cycle which is unsafe or unattainable.

The engine is an air pump, even if there's no fuel, if the engine is connected to the wheels and the wheels are turning, the engine keeps running and keeps pumping air. You still hear it running because it's still actively taking in air and pumping it through the engine and out the exhaust.

The fuel cut is a removal of the injector firing signal from the ECU. This is to say that your engine computer doesn't put fuel in the engine, hence the name.

Despite the rumors of fuel cut being caused by too low of fuel pressure, too small of injectors, high flowing exhaust, high flowing intake, or large turbos, fuel cut is not directly caused by any of these.

If your engine RPM's are above idle by some amount and your throttle pedal position (not the actual throttle position, the pedal) is below some threshold (say 1%) then the engine will cut fuel.

Engine keeps running even if there's no fuel

If your car's engine keeps running even if there's no fuel, it could be because the ECU (engine computer) is seeing more air entering the engine than it was originally programmed to use. This is known as a fuel cut, which is a removal of the injector firing signal from the ECU.

The feed flow of fuel is cut off by means of electrical shut-off valves in the event of a system failure, such as in the case of an accident. This is to avoid the risk of fire in the car.

The engine is an air pump, so even if there's no fuel, the engine will keep running and keep pumping air. You will still hear it running because it's still actively taking in air and pumping it through the engine and out the exhaust.

If your engine RPMs are above idle by some amount and your throttle pedal position is below some threshold, the engine will cut fuel.

If your car is not starting and displaying a "cut out fuel" message, you can try the following steps:

• Turn right turn signal switch ON
• Turn left turn signal switch ON
• Turn right turn signal switch ON
• Turn left turn signal switch ON
• Turn left turn signal switch off
• Turn ignition OFF
• Turn hazard flashers OFF

Fuel cut is not caused by low fuel pressure or small injectors

Fuel cut is a removal of the injector firing signal from the ECU and is not caused by low fuel pressure or small injectors. It is caused by the ECU seeing more air entering the engine than it was originally programmed to use. This is likely to correspond with an injector duty cycle which is unsafe or unattainable.

The engine is an air pump, even if there's no fuel, if the engine is connected to the wheels and the wheels are turning, the engine keeps running and keeps pumping air. You still hear it running because it's still actively taking in air and pumping it through the engine and out the exhaust.

Despite the rumors of fuel cut being caused by too low of fuel pressure, too small of injectors, high flowing exhaust, high flowing intake, or large turbos, fuel cut is not directly caused by any of these.

The feed flow of fuel is cut off by means of electrical shut-off valves in the event of failure of the system, eg: because of an accident. Thus the risk of fire in the car is avoided.

Frequently asked questions