Engine Controls - Theory & Operation: Other Kia Sephia II

AIR INDUCTION SYSTEM

All engines use the same basic air induction system. Remote air cleaner (with intake air temperature sensor) routes air through MAF sensor to plenum-mounted throttle body.

COMPUTERIZED ENGINE CONTROLS

All engines use Sequential Multiport Fuel Injection (SFI) and Distributorless Ignition System (DIS) controlled by Engine Control Module (ECM). Input devices supply ECM with signals which indicate operating conditions of the vehicle. ECM output signals control systems which control vehicle operation to optimize emission control and vehicle performance. On vehicles equipped with automatic transmission/transaxles, ECM also sends outputs to, and receives inputs from, Transmission Control Module (TCM).

ENGINE CONTROL MODULE (ECM)

The Engine Control Module (ECM), through various input sensors, monitors cranking signal, intake air amount, intake air temperature, air/fuel ratio, throttle valve opening angle, No. 1 piston compression stroke TDC, engine coolant temperature, engine RPM, vertical chassis movement, A/C operation, detonation, gear status (if automatic transmission/transaxle) and fuel tank pressure. ECM uses this information to control fuel injection timing and duration, ignition timing, idle speed, A/C cutout, fuel pump, purge control system and perform self-diagnostic functions.

ECM includes On Board Diagnostics-II (OBD-II) to monitor efficiency of emissions related components and systems. If an emissions related system malfunctions or deteriorates below preprogrammed performance criteria, OBD-II will illuminate the Malfunction Indicator Light (MIL) and store a Diagnostic Trouble Code (DTC). If a condition exists that may cause catalytic converter damage, MIL will flash continuously.

ECM LOCATION

Note. Components are grouped into 2 categories. The first category covers INPUT DEVICES , which produce voltage signals monitored by ECM. The second category covers OUTPUT SIGNALS , which are components controlled by ECM.

INPUT DEVICES

Vehicles are equipped with different combinations of input devices. Not all devices are used on all models. To determine input device usage on a specific model, see appropriate wiring diagram in WIRING DIAGRAMS article. Available input signals include the following

A/C Cut Relay

Sends A/C operation condition signals to ECM. On Sephia, located in engine compartment fuse/relay box. On Sportage, located below right side of instrument panel, behind glove box.

Camshaft Position (CMP) Sensor

CMP sensor detects No. 1 piston at TDC of compression stroke. ECM uses input for fuel and ignition control. Located at cylinder head.

Chassis Acceleration Sensor (CAS)

Detects vertical chassis movement on rough terrain. ECM uses signal for engine misfire detection determination. On Sephia, located right side of engine compartment near shock tower. On Sportage, located at lower right engine compartment below starter.

Crankshaft Position (CKP) Sensor

CKP sensor detects crankshaft angle. ECM uses input to determine engine speed, misfire detection, and for fuel and ignition control. Located on left side of transaxle or transmission flywheel housing.

Engine Coolant Temperature (ECT) Sensor

ECT sensor is thermistor whose resistance decreases as coolant temperature increases. Located near thermostat.

Fuel Tank Pressure Sensor (FTPS)

Detects fuel vapor leakage and monitors Purge Solenoid Valve (PSV) operation. Located on fuel tank.

Heated Oxygen Sensors (HO2S)

Generates voltage signal depending on oxygen content of exhaust. ECM uses input from front HO2S for calculating fuel mixture correction to fuel injector pulse width. Located in exhaust manifold. ECM uses input from rear HO2S to monitor effectiveness of Three Way Catalytic (TWC) converter. Located downstream from TWC converter.

Intake Air Temperature (IAT) Sensor

IAT is thermistor whose resistance decreases as intake air temperature increases. Input used by ECM to standardize MAF airflow data. Located in air cleaner housing.

Knock Sensor

Detects detonation in cylinders. ECM will retard timing based on this signal. On Sephia, located behind intake manifold support bracket. On Sportage, located on right side of engine above oil filter.

Mass Airflow (MAF) Sensor

Hot film type sensor. MAF sensor measures amount of air entering the engine. This measurement of airflow is a reflection of engine load (throttle opening). Main input used in fuel injector duration calculation. Located on air intake hose near air cleaner housing.

Throttle Position (TP) Sensor

Potentiometer whose resistance increases linearly as throttle is opened. Sends throttle angle signal to ECM. Located on throttle body.

Transaxle/Transmission Range Switch (A/T)

Signals shift lever position to ECM. Input used by ECM for idle speed control and load/no load determination. On Sephia, located on left side of transaxle. On Sportage, located on right side of transmission.

OUTPUT SIGNALS

The ECM processes information from input sensors and sends appropriate voltage control signals to the following engine controls

Controls A/C operation according to conditions. Will shut off compressor when engine coolant temperature gets too hot. On Sephia, located in engine compartment fuse/relay box. On Sportage, located below right side of instrument panel, behind glove box.

A/C Switch

Controls battery power to A/C cut relay.

Canister Close Valve (CCV)

Closes air inlet to Evaporative Emissions (EVAP) canister when ignition is turned off. Opened and closed by ECM to test EVAP system for leaks. Located near EVAP canister.

EGI Main Relay

Normally open. Controlled by ECM. Supplies battery voltage to electrical devices.

Fuel Injectors

Fuel is supplied to engine through electronically pulsed injectors. ECM controls amount of fuel by controlling duration of fuel injector pulse.

Fuel Pump Relay

Normally open. Controlled by ECM.

Idle Air Control (IAC) Valve

ECM controlled valve that allows air to bypass throttle valve. Controls idle speed.

Ignition Control Module

Controls operation of ignition coils. Integrated into ECM.

Leak Detection Pump (Sephia)

Valve is opened and closed by ECM command to test EVAP system for leaks. Located on EVAP canister. Sephia will have either leak detection pump or CCV.

Malfunction Indicator Light (MIL)

Also called CHECK ENGINE light. Warns of problem in emission system. See SELF-DIAGNOSTIC SYSTEM .

Purge Solenoid Valve (PSV)

When actuated by ECM allows fuel vapors to be purged from EVAP canister into intake manifold. Located near dynamic chamber (plenum). See FUEL EVAPORATION SYSTEM under EMISSION SYSTEMS.

FUEL DELIVERY - RETURNLESS SYSTEM (SEPHIA 1.8L)

Extra fuel is returned to fuel tank after passing through fuel filter located under car. Conventional system returns fuel after passing through fuel rail and pressure regulator. Eliminating fuel return from engine lowers fuel and fuel tank temperatures reducing evaporative emissions.

Fuel Delivery Module

Fuel delivery module consists of electric fuel pump, pressure regulator, fuel filter and fuel sender unit. Fuel delivery module is located in fuel tank.

Fuel Pressure Regulator

Fuel pressure regulator is pre-set. Modulates system pressure at return line to fuel pump. Located on fuel pump.

Fuel Pump

Fuel pump is electric pump controlled by ECM. One-way check valve maintains pressure when fuel pump is off. Located in fuel delivery module in fuel tank.

FUEL DELIVERY - CONVENTIONAL SYSTEM (SPORTAGE 2.0L)

Fuel is pumped from fuel tank mounted fuel pump through fuel rail to fuel injectors. Variable pressure regulator is mounted on fuel rail to control injector fuel pressure to about 40.5 psi (290 kPa) above manifold absolute pressure. Excess fuel is returned from fuel rail to fuel tank. System minimizes vapor lock by keeping fuel moving through fuel rail.

Electronic pump controlled by ECM through fuel pump relay. Control valve in fuel pump retains fuel pressure when pump is not running. Located in fuel tank as part of fuel pump assembly.

Fuel pressure regulator is a sealed unit, divided into 2 chambers (fuel and spring chambers) by a diaphragm. The fuel chamber receives fuel through fuel rail. Spring chamber is connected to intake manifold vacuum. The balance between calibrated spring pressure seating diaphragm against return pipe and vacuum pulling diaphragm away from return pipe, maintains injector fuel pressure at 40.5 psi (290 kPa) more than manifold absolute pressure. Located on end of fuel rail.

IAC solenoid is an electromechanical valve controlled by ECM. The IAC valve is mounted on intake manifold plenum and allows air to by-pass the throttle plate. The amount of air allowed to by-pass the throttle plate is controlled by a duty signal determined by ECM.

DISTRIBUTORLESS IGNITION SYSTEM (DIS)

DIS system consists of a Crankshaft Position (CKP) sensor, Camshaft Position (CMP) sensor and 2 coils. CKP sensor is located on transaxle/transmission case near flywheel. CMP sensor is located in rear of head. Coils are located directly on top of No. 2 and No. 4 spark plugs. Each coil is connected to companion cylinder spark plug by plug wire. System uses waste spark method. Each coil fires 2 spark plugs simultaneously. Sensors signal ECM which cylinder is ready to fire. The ECM then triggers appropriate coil.

EMISSION SYSTEMS

CO, HC and NOx emissions are controlled by Positive Crankcase Ventilation (PCV) system, Evaporative Emissions (EVAP) control system and catalytic converters.

FUEL EVAPORATION SYSTEM

Note. No information available from manufacturer on leak detection pump.

Fuel evaporation system prevents escape of raw fuel vapor to atmosphere. System components include fuel tank, EVAP canister, Canister Close Valve (CCV), Purge Solenoid Valve (PSV), Fuel Tank Pressure Sensor (FTPS), rollover valve, On-board Refueling Vapor Recovery (ORVR) valve (Sephia), catch tank (Sephia), check valve (Sportage), vapor separator (Sportage), leak detection pump (Sephia), fuel filler cap and Engine Control Module (ECM). ECM controls operation of PSV and CCV. PSV controls when fuel vapors are allowed to be drawn from EVAP canister into intake manifold so that they may be burned. CCV controls EVAP canister's vent to atmosphere.

ECM's On Board Diagnostics-II (OBD-II) runs monitors for large and small EVAP system leaks when vehicle is idling at a stop. ECM uses FTPS output to determine EVAP system pressure and pressure changes. At beginning of monitor, PSV is closed and CCV is commanded closed by ECM to measure compensation gradient. Compensation gradient is the increase in fuel tank pressure due to evaporation of fuel in fuel tank. After predetermined amount of time passes, CCV is opened and PSV is turned on. When PSV reaches 100 percent duty cycle, CCV is closed. If vacuum buildup, minus compensation gradient, is less than programmed threshold, gross leak is diagnosed. After maximum vacuum buildup, PSV is turned off (closed). If vacuum in fuel tank, minus compensation gradient, decreases to less than programmed threshold, small leak is diagnosed. CCV is opened and monitor is complete. If either gross leak, or small leak, is detected for 2 driving cycles, ECM assumes there is defect in evaporative emissions system and illuminates MIL.

PSV is normally closed, duty cycle-controlled valve located in vapor line between EVAP canister and intake manifold. When commanded open by ECM, fuel vapors collected in EVAP canister are allowed to be drawn into (purged) intake system.

Measures pressure and vacuum levels in fuel tank. ECM can check PSV operation and for leaks in EVAP system by monitoring fuel tank pressure data during different operating cycles. Located on top of fuel pump assembly.

POSITIVE CRANKCASE VENTILATION (PCV)

The PCV system uses intake manifold vacuum to eliminate crankcase pressure and recycle blow-by gasses. Manifold vacuum draws gases from crankcase, through PCV hose, into combustion chamber. The PCV valve is positioned in hose through which crankcase gases flow on their way to combustion chamber.

By opening and closing in direct relation to engine vacuum, the PCV valve meters crankcase gas flow to combustion chamber. During periods of high manifold vacuum, such as at idle and deceleration, valve is almost completely closed, limiting flow of gases. During cruise speeds, valve permits greatest flow of gases.

Under conditions in which excessively high amounts of crankcase pressure is produced (such as heavy load), system allows excess gases to flow back through crankcase vent hose and into intake tract.

Note. Loose fuel cap will cause MIL to illuminate.

Also called CHECK ENGINE light, MIL comes on when ignition is turned on. MIL remains on for several seconds after engine has started, then goes out. If ECM detects emission related component or systems deterioration or failure, MIL will illuminate and Diagnostic Trouble Code (DTC) is stored in memory. MIL will stay on until DTC is erased with scan tool or battery is disconnected for at least 20 seconds. If detected failure may cause catalytic converter damage, MIL will continuously flash on and off.