Honda Civic/Acura Integra

since 1994 release

Repair and operation of the car

System of stabilization of turns of idling – the general information, check of a state and replacement of the IAC valve

General information

When the engine works at single turns, the composition of air-fuel mix is controlled by system of stabilization of turns of idling (IAC). On the Civic models the system consists of RSM and the IAC valve, on the Integra models – of RSM, the thermosensitive valve of turns of bystry idling (FIT) and the IAC valve. Activation of the IAC valve is made at the command of ECM/PCM, depending on the current load of the engine (turning on of the conditioner of air, use of the power steering, unit temperature, etc.). the valve regulates the size of the air stream given to the inlet pipeline bypassing a butterfly valve. Obtains basic data of ECM/PCM from VSS, EST sensors, PSP sensors switches and operation of a clutch coupling of the К/В compressor. Depending on the current load of the engine the module as appropriate corrects turns of its idling. In order to avoid violation of stability of turns of idling at start of the engine the IAC valve opens at the time of a provorachivaniye and remains open right after start for some time, providing supply of additional air in the inlet pipeline.

Check

PERFORMANCE ORDER

1. Cock the parking brake, prop up car wheels antiretractable boots and transfer transmission to neutral transfer (RKPP) or to situation "P" (AT). According to instructions of manufacturers connect a tachometer to the engine. Start the engine and lift the frequency of its rotation to value of 3000 rpm. Wait for operation of the fan of the cooling system, then dump turns to single and disunite the electric socket of the IAC valve. Try not to touch fan blades with hands and not to allow hit in contact with them of hair and free elements of clothes. At a detachment of the valve there has to be a noticeable decrease in turns of the engine, otherwise the valve most likely is faulty. If falling of turns takes place, and the problem with support of their stability does not disappear, check a condition of a plait of an electrical wiring and its contact connections on the site between the IAC and ECM/PCM valve. 2a. Disconnect an electrical wiring from the IAC valve, include ignition (do not start the engine) and measure tension between the positive plug of the socket from a plait (the plug of a yellow-black wire) and the mass of a body (see accompanying illustrations): Civic models. The voltmeter has to register battery tension. If tension is absent, check a condition of a yellow-black wire of an electrical wiring on the site between the IAC valve and the main PGM-FI relay. Anyway leave the socket disunited for performance of further checks. 2b. Integra model valve. 3. If the plait of an electrical wiring of IAC consists of two wires, connect the valve by means of two wires crossing points directly to the battery (to the positive plug the black-yellow wire, is connected to negative – black-blue). The valve has to publish click every time when giving food. Do not hold the valve powered longer than it is necessary to catch click! 4. If the plait consists of three wires, connect the negative probe of an ohmmeter to the central plug of the socket, and positive – serially to each of side. In both cases the device has to register resistance of 16÷28 Ohms. 5. At positive results of the checks stated in paragraphs 3 and 4 the car it is necessary to drive away on car repair shop for more detailed diagnostics of a condition of ECM/PCM and a contour of the IAC valve.

Replacement

PERFORMANCE ORDER

1. Disconnect an electrical wiring from the IAC valve. 2. Turn out two fixing screws and remove the sensor from the delivery camera of an air path (see illustrations above). 3. Installation is made upside-down. Do not forget to replace a sealing ring.