Kia Carens. Manual — part 89

2001 > 1.8L DOHC >

Description

Conventional

Today's most engines have more than 90% of the returning fuel to the tank in normal operational condition.
Temperature of the fuel being returned through the return line is raised by about 7~15°C as it absorbs cooling heat from
underbody, fuel line, pipe friction, ect. in its course of travel.
The heated returning fuel continuously circulates and increases the temperature of the fuel in the fuel tank in the process.
At the same time, the fuel subjected to a pressure of 2.5~3.0kg/cm² at the fuel line is placed under near atmospheric
pressure as it passes through the pressure regulator.
In this occasion, a rapid evaporation of gasoline occurs being with its constituents having lower evaporation points, and
the evaporated has is pushed toward the fuel tank.
The evaporated gas so generated is discharged to the atmosphere as it exceeds the storage limit of the vehicle.

Returnless system

In Returnless Fuel System, the returning line from distribution pipe to fuel tank has been removed, eliminating the
possible evaporation of gasoline from return line heated by engine and dunk line heated by friction.
Moreover, by installing a pressure regulator in the fuel tank, the amount of gas evaporated as a result of pressure dropin
return line of the pressure regulator is decreased by about 60-20% compared with conventional fuel system.
In addition, by installing a jet pump in Fuel Delivery Module, the fuel supplied to the module is smoothly provided to the
fuel pump and helps maintain stable fuel delivery when fuel level is low.
The system further prevents possible hunting when the vehicle runs at corner or along slopes, and reduces the amount of
ineffective residual fuel.

Fuel delivery module

1. The fuel delivery module is installed in the fuel tank.

The fuel delivery module consist of following.

A. Electric fuel pump
B. Pressure regulator

C. Fuel filter
D. Fuel sender unit

E. Fuel supply line connection

Electric fuel pump

The electric fuel pump is located in the fuel delivery module. It is mounted with and connected to the fuel sensor unit.
The fuel pump is an electric pump controlled by the engine control module(ECM) through the pump relay.
The motor rotates and impeller within the pump assembly. This causes fuel within the fuel tank to be drawn into the
fuelinlet port. Fuel is pumped out to fuel injectors under pressure through the fuel feed pipes and hoses.
Fuel pressure is retained when the fuel pump is not running by means of a one-way check valve located within the pump.

Fuel pressure regulator and injector

The fuel pressure is regulated by a fuel pressure regulator.
The injectors are directly supplied with battery voltage through the main relay. Fuel is metered and injected into the intake
ports according to the signals received from the ECM.
When these injection signals are applied to the solenoid coil of the injector, the needle valve is pulled off its seat.
Fuel is then injected into the intake port.
The amount of fuel supplied to the engine depends on the duration of time the injectors stay open.

Fuel sender assembly

The fuel sender system consists of a float, float arm, and a variable resistor. Fuel level is measured by the position ofthe
float in the fuel tank, and is indicated by a gauge in the instrument panel cluster assembly. When the fuel level changes,
the float position changes. The change in float position increases or decreases the resistance of the variable resistor. The
change in resistance causes the position of the fuel gauge readout to change.

Fuel pipes and hoses

Fuel feed and return pipes(lines) and hoses carry fuel from the tank to the fuel rail. these pipes and hoses are attached to
the underbody of the vehicle and must be inspected for kinks or dents which may restrict fuel flow.
Fuel vapor pipes and hoses carry fuel vapors from the fuel tank to the evaporative emissions canister located installer at
below underbody. The fuel vapors are stored in the canister when the engine is not running. When the engine is running
at normal operating temperature, and the accelerator pedal is depressed, the engine control module(ECM) will command
theevaporative emission solenoid purge valve to open and allow the stored fuel vapors to be purged into the intake
manifoldand be absorbed into the combustion process.

Fuel rail

The fuel rail supplies the necessary fuel to each individual fuel injector is mounted to the intake manifold.
The fuel pressure regulator is no longer mounted to the fuel rail. It is now located in the fuel tank on the fuel delivery
module.

Service valve

Service valve is located on the fuel rail and used for air bleeding after vehicle launch or maintenance.

Quick connector

Improved serviceability has been achieved to use a quick connector which enables easy and simple connection
disconnection of fuel rail. Refer to "Quick connector" for removal/installation.

2001 > 1.8L DOHC >

Component

2001 > 1.8L DOHC >

Releasing fuel system pressure

THE FUEL SYSTEM RENAINS UNDER PRESSURE WHEN THE ENGINE IS NOT RUNNING. RELEASE
FUEL SYSTEM PRESSURE BEFORE DISCONNECTINGANY FUEL LINE TO REDUCE THE CHANCE
OF PERSONAL INJURY OR FIRE DAMAGE TO VEHICLE COMPONECTS.

1. Start engine.

2. Disconnect fuel pump connector located below rear seat cushion.

3. Let engine stall, then turn OFF ignition switch.

4. Reconnect fuel pump connector.

Fuel line handling

FUEL IS EXPLOSIVE. WHEN WORKING ON FUEL SYSTEM MARK SURE TO SUPPLY ADEQUATE
VENTILATION TO THE WORK AREA. DO NOT SMORKE, AND KEEP SPATKS AND OPEN FLAMES
AWAY.

1. When disconnecting fuel hose quick connectors, use shop towels to adsorb fuel, protecting equipment and

personnel.

Priming the fuel system

After fuel pressure has been released, system must be primed to avoid excessive cranking to restart the
engine. Follow steps below:

1. Connect data link connector terminals FUEL PUMP and B+ with a jumper wire.

2. Turn ignition ON for no longer than 10 seconds to pressurize system and check for fuel leaks. (Jumper wire

gets hot if it is left in for longer than 10 seconds.)

3. Turn ignition switch OFF and remove jumper wire.

Fuel pressure hold inspection

1. Disconnect negative battery terminal.