Deceleration Control System

Deceleration Control System:

SYSTEM OVERVIEW
Dashpot:
Prevents the throttle valves from closing suddenly.

Idle air control valve:
Prevents afterburn, air is supplied to intake manifold during deceleration.

Fuel cut control:
Improves fuel economy and prevents engine bucking during deceleration.

Air bypass valve:
Bypasses compressed air from the turbocharger to air cleaner housing during deceleration to prevent noise.


Dashpot Inspection




1. Open the throttle valve fully, then push the dashpot rod with a finger and verify that the rod goes in slowly.
2. Release the rod and verify that it comes out quickly.
3. Replace it, if necessary.

Adjustment
1. Warm up the engine to the normal operating temperature and run it idle.
2. Verify that the fast idle cam separates.
3. Turn all electrical loads OFF.




4. Connect a tachometer to the data link connector terminal IG-.




5. Open the throttle valve until the dashpot rod separates from the lever.
6. Check the engine speed when the dashpot rod touches to the lever.

Engine speed: 2600-3000 rpm




7. Loosen the locknut and adjust by turning the dashpot, if necessary.




Anti-Afterburn Control Inspection
1. Start the engine and run it at idle.
2. Disconnect the idle air control valve connector.
3. Increase the engine speed to over 4000 rpm then decrease the engine speed rapidly.
4. Verify that the engine speed decreases roughly at 1500-1000 rpm.