Thermal fast idle valve (engine V16A5)
Description
To prevent movement instability when the engine warms up, it is necessary to increase the idle speed. The thermal fast idle valve is controlled by a thermoparaffin plunger. When the engine is cold, the engine coolant surrounding the thermowax compresses the plunger, allowing additional air to be bypassed into the intake manifold so that the idle speed increases. When the engine reaches operating temperature, the valve closes, reducing the volume of air bypassed into the intake manifold.
Inspection
Note: The thermal fast idle valve is factory adjusted and should not be disassembled.
1. Remove the inlet air pipe from the throttle body.
2. Start the engine.
3. Close the lower inlet in the throttle body with your finger and make sure there is air flow when the engine is cold (Engine coolant temperature below 30°C).
If not, replace the thermal valve and check again.
4. Start the engine. Leave the engine at 3000 rpm without load (in position [N] or [P]) until the radiator fan comes on, then let it idle.
5. Check that the valve is completely closed. If the valve is leaking air, the idle speed will drop when you close the lower intake. Check the engine coolant level and the presence of air in the engine cooling system. If ok, replace the thermal valve and check again.
Setting the idle speed
Inspection/Adjustment
D15Z6 engines (M/T), D15Z7 (M/T), D16Y5 (M/T), D16Y6 (M/T) D16Y8 (M/T), В16А2, В16А4, В16А5, В16А6:
Note: Before setting the idle speed, check the following:
- MIL did not light up.
- Ignition advance.
- Spark plug.
- Air filter.
- PCV system.
1. Attach the tachometer.
2. Start the engine. Leave at 3000 rpm no load (A/T in N or P position, M/T in neutral) until the radiator fan comes on, then let it idle.
3. Disconnect the 2K connector from the idle air control valve (IAC).
4. Start the engine with the accelerator pedal lightly pressed. Hold the engine speed at 1000 rpm, then slowly release the pedal while the engine is idling.
5. Check idle speed under no-load conditions: headlights, fan, rear window defogger, radiator fan and air conditioner do not operate
Note (model KS): remove fuse No. 18 (7.5A) in the underpanel fuse box and turnip, then check that the headlights and lights do not come on.
The idle speed should be:
If necessary, adjust the idle speed. turning the adjusting screw.
Note: After adjusting the idle speed at this point, check the ignition timing. If not within specification, proceed to step 4.
6. Turn off the ignition.
7. Connect the 2K connector to the idle air control valve, then remove the auxiliary (RADIO) fuse (7.5A) in the engine compartment fuse and relay box for 10 seconds to reset the memory of the electronic engine control unit/automatic transmission (ECM/RSM).
8. Start the engine again and let it idle without load for one minute, then check the idle speed.
Note (model KS): remove fuse No. 18 (7.5A) in the under-panel fuse and relay box, then check that the headlights and lights are off.
The idle speed should be:
- Engine D15Z7: M/T: 650±50 rpm
- Engine D16Y8 (KN model) M/T: 670±50 rpm
D15Z6 engines (except for the K5 model), В16А4, В16А5
D15Z6 engines (model KS), D16Y5, D16Y6, D16Y8 (except for the KN model), В16А2, В16А6
9. Let the engine idle for 1 minute with the headlights ON (low beam) and check the idle speed.
The idle speed should be (all engines):
10. Turn off the headlights. Leave the engine idling for one minute with the heater fan switch on Hi and the air conditioner switch ON, then check the idle speed. The idle speed should be:
In addition to the V16A5 engine:
- Engine V16A5: A/T: 830 + 50 rpm in position [N] or [P]
D15Z6 engines (A/T), D1527 (CVT), D16Y5 (CVT), D16Y6 (A/T), D16Y7, D16V8 (A/T):
Adjust idle speed using Honda PRM-TESTER.
If not adjusted, check the following:
Note: Before setting idle speed, check the following:
- MIL did not light up
- Ignition timing
- Spark plug
- Air filter
- Crankcase ventilation system
1. Attach the tachometer.
2. Start the engine. Leave at 3000 rpm without load (A/T in N or P position, M/T in neutral) until the radiator fan comes on, then let it idle.
3. Check the idle speed under no-load conditions: the headlights, fan, rear window defroster, radiator and air conditioning fans do not operate.
- Engine D16Y7 (KN model M/T) — 670±50 rpm
D15Z6 engines (A/T), D15Z7 (CVT) b D16Y5 (CVT), D16Y6 (A/T), D16Y7, D16Y8 (A/T):
A/T: 700±50 rpm in position [N] or [P]
D16Y5 engines (model KQ), D16Y6, D16Y7 (models KK, KM):
4. Adjust the idle speed, if necessary, by turning the adjusting screw 1/2 turn clockwise and then clockwise.
Note: When removing the air filter housing, do not disconnect the intake air temperature sensor connector.
5. After tightening the idle adjustment screw ½ turn, check the idle speed again.
Note: Do not tighten the idle speed screw more than ⅓ without checking the idle speed.
6. Leave the engine idling for 1 minute with the heater fan switch on Hi and the air conditioner on, then check the idle speed.
The idle speed should be (all engines):
Note: Do not tighten the idle speed screw while the fan is on.