Why won't the engines start or stay running in FSX?

In FSX and FSX: Steam Edition, an engine that will not start or stay running is usually missing fuel, mixture, ignition or starting power, or a controller is forcing a lever back to cut-off. Test Ctrl+E in a new flight with a default aircraft, then use the failed-start symptom to identify the cause.

Engine not starting: what should I check first?

Start with the controls required for fuel and combustion; reinstalling FSX will not correct an empty selected tank or a mixture lever held at cut-off.

1. Confirm that usable fuel is aboard. Open the Fuel and Payload window and inspect each tank, not only the total quantity. Select BOTH, ON or a tank that contains fuel, depending on the aircraft.
2. Configure a piston engine. Set the propeller control forward, move the mixture towards rich, select the magnetos and open the throttle slightly. At a high-elevation airport, lean the mixture gradually if the starter turns but the engine will not fire.
3. Configure a turbine engine. Leave the throttle at idle and the fuel or condition lever at cut-off while the starter begins turning the engine. Move the fuel control to idle only after the required rotation has developed. The exact point is aircraft-specific.
4. Supply starting power and ignition. An electric piston starter usually needs battery and master power. A jet or turboprop may require an APU, external power, ignition, fuel pumps and pneumatic start air.
5. Try the automatic start. Give the simulator window keyboard focus, press Ctrl+E once and let the sequence finish. Do not keep moving a throttle quadrant while FSX is trying to position the controls.
6. Check the selected engine. A previous engine-selection command may have left FSX controlling only one engine. Compare the starter, fuel, mixture and ignition positions for every engine.

What does the failed start symptom mean?

The stage at which the start fails usually reveals which system needs attention.

If there is no starter movement at all, fuel cut-off is not the first fault to solve. Establish starter power and engine selection before changing fuel controls.

What if the fuel control is already at cut-off and the command is not running?

A fuel cut-off command stops fuel flow, so no visible response is expected if the control is already at cut-off.

On a piston aircraft, move the mixture away from idle cut-off and towards rich before starting. On a turbine aircraft, beginning at cut-off is normally correct: engage the starter first, verify that the engine is rotating, then move the start, condition or fuel lever to idle at the checklist point. Moving it to cut-off again will not start the engine.

If the idle or rich command still does nothing, watch the cockpit lever while operating the control:

• The lever never moves: the command may be unassigned, the wrong engine may be selected, or the add-on may use a custom cockpit control that ignores generic FSX mixture commands.
• The lever moves and snaps back: a mixture or condition axis is overriding the keyboard. Check every connected controller because FSX can assign the same axis to more than one device.
• The lever moves but there is no combustion: check fuel quantity, the selected tank, pumps, ignition and starter rotation.
• The engine starts only with a cockpit clickspot: use the aircraft's own procedure. Detailed add-ons often replace the default FSX starting logic.

For aircraft that require a full cold-and-dark sequence, our FSX manual-start guidance for piston, turboprop and jet aircraft explains the roles of electrical power, starters, bleed air and fuel controls.

Why doesn't Ctrl+E start the engines?

Ctrl+E should start the default FSX aircraft, but it cannot overcome a missing command assignment, a hardware axis holding fuel at cut-off or custom add-on logic.

• Confirm that automatic engine start is still assigned in the Controls settings.
• Make sure the main simulator window, rather than a text field or another application, has keyboard focus.
• Release all controller levers and watch whether the virtual mixture or fuel control moves back after the automatic sequence changes it.
• Check whether FSX is controlling all engines rather than only one.
• Test a default aircraft. If it starts, FSX's basic start command works and the original aircraft needs its own checklist or saved-state correction.

Should Ctrl+E start the default FSX 737?

The default FSX Boeing 737-800 should normally respond to Ctrl+E, provided that fuel is aboard and a controller is not forcing its fuel controls back to cut-off.

For a manual start, establish electrical power, start the APU, supply generator power and bleed air, place an engine start switch in the ground-start position, and wait for N2 rotation. Then move that engine's start lever from cut-off to idle and monitor the engine until it stabilises before starting the other side.

An advanced add-on bearing the same aircraft name may use different systems and may deliberately ignore Ctrl+E. Follow that add-on's checklist rather than assuming the default 737 sequence applies.

Why does the engine start and then immediately stop?

An engine that fires and dies within seconds is usually losing fuel or receiving a second cut-off command.

• Mixture-axis override: Ctrl+E moves the virtual control, but a physical lever at minimum sends it back to cut-off. Duplicate assignments across a joystick and throttle quadrant are a common cause.
• Wrong or empty selected tank: fuel elsewhere in the aircraft cannot feed the engine if its selected source is empty or closed.
• Throttle fully closed: some piston aircraft need the throttle cracked open to maintain idle. Add-ons may also model an idle gate.
• Ignition switch override: a hardware switch can return the virtual magnetos to OFF when its spring-loaded start position is released.
• Add-on protection: a detailed aircraft may shut down after low fuel pressure, a hot start, an omitted valve or pump step, or damage recorded by its maintenance system.

Switching off the battery after a conventional piston engine starts should not normally stop its self-powered magneto ignition. If the engine dies, inspect the magnetos, fuel supply and mixture rather than treating the battery as the only possible cause.

Why does the engine quit during take-off?

An engine that idles correctly but stops when power is applied usually has a fuel-delivery, mixture, controller or simulated-failure problem rather than a starter fault.

• Watch the cockpit levers while advancing the throttle. A duplicate or cross-assigned axis may move the mixture, propeller or condition control at the same time.
• Check the tank actually feeding the engine, along with any pumps, crossfeed valves and selectors modelled by the aircraft.
• Adjust piston mixture for airport elevation. A badly rich or lean setting can cause poor power or engine stoppage.
• Inspect scheduled FSX failures and any separate add-on wear, damage or maintenance system.

If failures keep returning, use our instructions for clearing FSX damage, scheduled failures and mission-related shutdowns.

I followed the steps and still nothing happens: what should I do?

A clean default-aircraft test separates an FSX-wide control problem from a faulty saved state or aircraft-specific procedure.

1. Close FSX and disconnect external controllers. This prevents a throttle quadrant, joystick or switch panel from changing the cockpit as the flight loads.
2. Create a new Free Flight. Select the default Cessna 172 at a low-elevation airport, add fuel and ensure that no engine failure is active. Do not load the situation that was failing.
3. Set the basic controls. Select a fuel source containing fuel, set mixture rich, magnetos appropriately and open the throttle slightly.
4. Press Ctrl+E once. If the engine starts and remains at idle, the simulator's basic engine and automatic-start logic is working.
5. Reconnect controllers one at a time. When the problem returns, inspect that device for throttle, mixture, propeller, condition, magneto, starter and per-engine assignments.
6. Test the original aircraft last. If only that aircraft fails, use its checklist and inspect its own panel-state, maintenance and interlock options.

If the first attempt did not work and there is still no starter movement in the default Cessna, restore the automatic-start and starter assignments before considering configuration changes. If corrected bindings disappear after restarting FSX, follow our steps for stopping FSX controller assignments from reverting.

Can a saved flight prevent the engines from starting?

Yes. A saved flight can restore mixture, magnetos, fuel selectors, engine selection and electrical switches in an unfavourable state.

Some add-ons also save their panel and maintenance state separately from the FSX flight. A genuinely new flight with a default aircraft is therefore a better diagnostic test than repeatedly loading the same situation. Reinstallation should be the last resort because it rarely fixes saved cut-off controls, an empty selected tank or a controller override.

Does this advice also apply to MSFS 2020?

No. Microsoft Flight Simulator 2020 has similar fuel, ignition and controller failure modes, but its assistance options, controller profiles, aircraft systems and menu structure differ from FSX.

If the problem is in MSFS 2020 rather than FSX or FSX: Steam Edition, use our dedicated MSFS engine-start and take-off shutdown troubleshooting. Do not copy FSX menu instructions or assume that an FSX add-on starting procedure applies there.