Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Bypass Air Control
When in deceleration mode, the turbocharger rotates additionally due to the inertial mass of shaft, compressor, and turbine wheel
. When the throttle valve quickly closes, the throttle valve upstream condition becomes low discharge rate and high charge rate, resulting in backflow of extra pressure to pressurized air. This places counter-rotating force on compressor wheel
. (Brief beat noise and mechanical stress.) To prevent this pumping, ECM opens the divert air switchover valve
to release surplus pressure to the upstream of turbocharger.
|
A |
Intake air |
|
B |
Exhaust gas |
|
C |
From exhaust manifold |
|
D |
To Throttle valve |
When the engine is not running, the divert air switchover valve is closed because the diaphragm is pushed back by the spring built in divert air switchover valve
. When in engine load mode, the divert air switchover valve is kept closed by the boost pressure- placed diaphragm. When the throttle valve is closed and ECM detects deceleration mode, ECM controls the divert air switchover valve. The diaphragm is turned down against spring force and boost pressure, and the divert air switchover valve is opened to release surplus pressure.
When the engine mode is switched from deceleration mode to load mode, the divert air switchover valve is not controlled anymore. The diaphragm is pushed back by the spring and boost pressure, and the bypass switchover valve is closed again.
|
|
Boost pressure control flap vacuum actuator |
|
|
Noise damper |
|
|
Turbocharger |
|
A |
Status: Closed |
|
B |
Status: Opened |
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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