Nissan Maxima QX

since 1993 release

Repair and operation of the car

Check of a state and replacement of components of system of stabilization of turns of idling

Working in a motive compartment, try not to allow hits of hands, hair and details of clothes in contact with moving components, such as driving belts, blades of a krylchatka of the fan, etc.

Valve of stabilization of turns of idling (IAC)

When the engine works at single turns, the composition of air-fuel mix is controlled by means of the valve of stabilization of turns of idling (IAC). Activation of the IAC valve is made at the command of RSM, 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 RSM 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 of the last and remains open right after start for some time, providing supply of additional air in the inlet pipeline.

CHECK

PERFORMANCE ORDER

Implementation of the procedure described below can lead to entering in memory of OBD of malfunction which will be highlighted by a control lamp "Check the engine". Upon completion of check and the corresponding recovery repair do not forget to clear memory of system (see the Section System of Onboard Diagnostics (OBD) - the principle of functioning and codes of malfunctions).

1. Check serviceability of giving for the supply voltage valve. Disconnect an electrical wiring from the valve. Include ignition. Ground the negative probe of the voltmeter on weight and serially probe the positive probe of each two plugs of red wires of a plait of an electrical wiring of the socket, - the measuring instrument has to register battery tension, otherwise check a condition of an electrical wiring on sites of a chain between the ECCS relay and the battery (do not forget about safety locks) both the ECCS relay and the IAC valve (see schemes of electric connections at the end of the Head Onboard electric equipment).

2. For valve check of IAC measure resistance between the corresponding plugs of its contact socket. At a temperature of 20 °C resistance has to equal about 30 Ohms. If it is not possible to reveal any deviations, the car should be driven away on car repair shop for detailed diagnostics of RSM.

REPLACEMENT

PERFORMANCE ORDER

1. Disconnect an electrical wiring from the IAC valve.
2. On models 1993 and 1994 of of the issue disconnect a hose from a valve casing. Turn out four fixing bolts and release the valve from the inlet pipeline.
3. On models since 1995 turn out the issue two fixing screws and take the valve from a casing.
4. Wipe with pure rags the external surface of the valve and a wall of its landing nest.

Do not wash out the valve any solvent at all!

5. Put a new sealing ring in a casing and oil it liquid lubricating.
6. Install the valve on the regular place and strongly tighten fixture.
7. Further installation is made as it should be the return to an order of dismantle of the corresponding components.

Electromagnetic valve of management of turns of bystry idling

On models since 1995 the issue provided two electromagnetic valves of management of turns of bystry idling. Valves provide stability of turns of the engine regardless of change of the current loading. One valve is activated at operation of the power steering, the second - at turning on of the conditioner of air. Activation of valves leads to increase in intensity of the air stream which is soaked up in the inlet pipeline. System failure is not monitored by OBD.

CHECK

PERFORMANCE ORDER

1. Start the engine and against the stop turn a steering wheel in any party, then return it to the central situation, - turns of the engine should not change, inclusion To/in also should not lead to change of turns, otherwise make check of a condition of the corresponding electromagnetic valve.

And — the Electromagnetic valve of compensation of the increase in loading connected with functioning of the power steering
In — the Electromagnetic valve of compensation of the increase in loading connected with functioning To/in

2. Disconnect an electrical wiring from the electromagnetic valve. Connect the positive probe of the voltmeter to the plug of a red-yellow or yellow-blue wire of a plait of wires on the socket. Ground the negative probe. At the included ignition and To/in on the socket of the valve B battery tension has to take place, otherwise it is necessary to check a condition of an electrical wiring on the site of a chain between the valve and the assembly block of safety locks (do not forget to check a condition of the corresponding safety locks). If the clutch coupling of the K/V compressor does not work at inclusion of system, check also a condition of the corresponding relay. Check a condition of the PSP sensor switch (see the Section Check of a State and Replacement of the Sensor Switch of Pressure in system of hydrostrengthening of a wheel (PSP)) and quality of its grounding.
3. Switch off ignition. by means of couple of wires crossing points give a power supply from the battery on plugs of the corresponding electromagnetic valve, - distinctly heard click has to sound, otherwise the valve should be replaced. Remove the valve (see below) and check freedom of movement of its plunger. If the plunger is jammed, or the fixing spring is broken, the valve is also subject to replacement.

REPLACEMENT

PERFORMANCE ORDER

1. Disconnect an electrical wiring from the electromagnetic valve of management of turns of bystry idling.
2. By means of a wrench release the valve from an IAC valve casing.
3. Replace a copper sealing washer, then screw the valve on the regular place and strongly tighten it.
4. Further installation is made as it should be the return to an order of dismantle of the corresponding components.

Cam of bystry idling

The cam of bystry idling is a thermoelement and the issue for increase in turns of idling at start of the cold engine is used on models since 1995. Until the engine got warm a plunger of a thermoelement remains in the normal situation and the cam of bystry idling makes impact on the lever of the drive of a butterfly valve, a slega taking away it from an emphasis that leads to increase in turns of idling of the engine. In process of warming up of the engine the plunger is involved and develops a cam thus. That the lever comes back to basic situation.

CHECK AND ADJUSTMENT

PERFORMANCE ORDER

1. Disconnect an electrical wiring from the eats sensor and connect an ohmmeter to two plugs of the last (see the Section Check of a State and Replacement of the Sensor of Temperature of Cooling Liquid of the Engine (EST)).

2. Start the engine and watch change of resistance of the sensor of temperature. When resistance of the sensor reaches value 1650 ÷ of 2400 Ohms, the long tag on a cam of bystry idling has to be combined by the central part of a finger of the executive lever.

3. You do not suppress the engine, - when resistance of the eats sensor falls to the Ohm level 260 ÷ 390, the short tag of a cam has to be combined with the central part of a finger, otherwise it is necessary to weaken a lock-nut and rotation of the adjusting screw to achieve the required result.
4. If in a cam does not give in to adjustment, it is necessary to make replacement of the case of a throttle (see the Head of the Power supply system and release).