Purpose, Function
By lengthening the exhaust passage, the transmission of exhaust pressure waves to other cylinders can be delayed, and the amount of gas exhausted from a cylinder and forced back inside the combustion chamber is reduced By reducing the residual gas, the temperature inside the combustion chamber is reduced and the occurrence of knocking even at a high compression ratio is inhibited.
Construction
The exhaust manifold is installed to the rear of the engine. In addition, the catalytic converter (WU-TWC) is integrated (WU-TWC).

When the No.1 cylinder is at the intake stroke, the No.3 cylinder is at the exhaust stroke. By inducing the high temperature gas exhausted from the No.3 cylinder into the No.1 cylinder, the high temperature gas in the No.1 cylinder remains. If the amount of residual gas is high, the temperature in the combustion chamber rises and knocking can easily occur. With the 4-2-1 exhaust system, the transmission of exhaust pressure waves between each cylinder is delayed by the long exhaust pipes.

Exhaust System Removal/InstallationCheck Valve Inspection
Except U.S.A. And CANADA
1. Remove the check valve..
2. Verify that there is no airflow when positive pressure is applied to port
A.
If there is airflow, replace the check valve..
3. Verify that there is no airflow when negative pressure is applied to port
A.
If ther ...
Manifold Absolute Pressure (Map) Sensor/Intake Air Temperature (Iat) Sensor
No.2 Removal/Installation
NOTE:
Because the IAT sensor No.2 is integrated in the MAP sensor, replacing the
IAT sensor No.2 includes replacement of the MAP sensor/IAT sensor No.2.
1. Disconnect the negative battery cable..
2. Disconnect the MAP sensor/IAT sensor No.2 connector.
3. Remove the MAP sensor/IA ...
Low Engine Coolant Temperature Indicator Light (Blue)/High Engine Coolant Temperature
Warning Light (Red)
Purpose
Low engine coolant temperature indicator light (blue)
The low engine coolant temperature indicator light (blue) notifies the driver
that the engine coolant temperature is low and vaporization of the fuel is difficult.
High engine coolant temperature warning light (red)
...