gas type DODGE NEON 1999 Service Repair Manual

(6) Disconnect the rear brake flex hose tube from
the wheel cylinder (Fig. 94).
(7) Remove park brake actuator lever from the
park brake cable.
(8) Position a 1/2 wrench over the retainer fingers
on the end of the parking brake cable (Fig. 95). Com-
press cable housing retaining fingers and start cable
housing out of support plate (Fig. 95). Remove
wrench when retainer is free from the park brake
cable mounting hole in the rear brake support plate.
Alternate method is to use a aircraft type hose clamp
over cable housing end fitting compressing the three
fingers.
(9) Remove the 4 brake support plate to knuckle
attaching bolt and washer assemblies. Separate
brake support plate from rear suspension knuckle.
INSTALL
(1) Install brake support plate and gasket on rear
suspension knuckle casting. Torque support plate toknuckle casting attaching bolts to 75 N´m (55 ft.
lbs.).
(2) Insert parking brake cable end fitting into
brake support plate.
(3) Hand start hydraulic brake hose tube fitting to
wheel cylinder. Torque tube nut to wheel cylinder fit-
ting to 17 N´m (145 in. lbs.).
(4) Attach parking brake cable to the parking
brake actuator.
(5) Install rear brake shoe assemblies on the brake
support plate. Refer to Rear Brake Shoes in the
Removal And Installation Section in this group of the
service manual for the proper brake shoe assembly
installation procedure.
(6) Install rear hub and bearing assembly on rear
spindle. Install aNEWhub and bearing assembly
retaining nut (Fig. 93). Torque hub and bearing
assembly retaining nut to 217 N´m (160 ft. lbs.).
Install dust cap.
(7) Adjust brake shoes assemblies so as not to
interfere with brake drum installation.
(8) Install brake drum. Adjust and bleed service
brakes.
(9) After brake drums are installed, pump brake
pedal several times to do final adjustment of the
brake shoe assemblies.
(10) Install the wheel and tire assembly. Tighten
the wheel mounting stud nuts in proper sequence
until all nuts are torqued to half specification. Then
repeat the tightening sequence to the full specified
torque of 135 N´m (100 ft. lbs.).
REAR BRAKE WHEEL CYLINDER
REMOVE
(1) Raise vehicle on jack stands or centered on a
frame contact type hoist. See Hoisting in the Lubri-
cation and Maintenance section of this manual, for
Fig. 93 Rear Hub/ Bearing Retaining Nut
Fig. 94 Brake Flex Hose Tube At Wheel Cylinder
Fig. 95 Removing Park Brake Cable From Support
Plate
5 - 38 BRAKESPL
REMOVAL AND INSTALLATION (Continued)

SELECTION AND ADDITIVES
The use of aluminum cylinder heads, intake mani-
folds DOHC, and water pumps requires special corro-
sion protection. MopartAntifreeze or the equivalent
is recommended for best engine cooling without cor-
rosion. When mixed only to a freeze point of -37ÉC
(-35ÉF) to -59ÉC (-50ÉF). If it looses color or becomes
contaminated, drain, flush, and replace with fresh
properly mixed solution.
COOLING SYSTEM PRESSURE CAP
The cooling system is equipped with a pressure cap
that releases built up pressure, maintaining a range
of 97-124 kPa (14-18 psi).
The cooling system will operate at higher than
atmospheric pressure. The higher pressure raises the
coolant boiling point thus, allowing increased radia-
tor cooling capacity.
There is a vent valve in the center of the cap that
allows a small coolant flow from the coolant reserve
system (CRS) tank. This valve is spring loaded in the
closed position. However it must be free to open dur-
ing system cool-down.If the valve is stuck shut,
the radiator hoses will collapse on cool-down.
Clean the vent valve (Fig. 7) to ensure proper
sealing function.
There is a gasket in the cap that seals to the top of
the filler neck so that vacuum is maintained to draw
coolant back into the system from the coolant reserve
system (CRS) tank.
RADIATOR HOSES AND CLAMPS
WARNING: IF VEHICLE HAS BEEN RUN
RECENTLY, WAIT 15 MINUTES BEFORE WORKING
ON VEHICLE. RELIEVE PRESSURE BY PLACING A
SHOP TOWEL OVER THE CAP AND WITHOUT
PUSHING DOWN ROTATE IT COUNTERCLOCKWISE
TO THE FIRST STOP. ALLOW FLUIDS TO ESCAPE
THROUGH THE OVERFLOW TUBE AND WHEN THE
SYSTEM STOPS PUSHING OUT COOLANT AND
STEAM AND THE PRESSURE DROPS CONTINUE
SERVICE.
WARNING: CONSTANT TENSION HOSE CLAMPS
ARE USED ON MOST COOLING SYSTEM HOSES.
WHEN REMOVING OR INSTALLING, USE ONLY
TOOLS DESIGNED FOR SERVICING THIS TYPE OF
CLAM. ALWAYS WEAR SAFETY GLASSES WHEN
SERVICING CONSTANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps. If replacement
is necessary, use only a original equipment clamp
with matching number or letter.The hose clamps are removed by using Special Tool
6094 or equivalent constant tension clamp pliers
(Fig. 8) to compress hose clamp.
A hardened, cracked, swollen or restricted hose
should be replaced. Do not damage radiator inlet and
outlet when loosening hoses.
Radiator hoses should be routed without any kinks
and indexed as designed. The use of molded hoses is
recommended.
Spring type hose clamps are used in all applica-
tions. If replacement is necessary replace with the
original Mopartequipment spring type clamp.
ENGINE BLOCK HEATER
The heater is mounted in a core hole (in place of a
core hole plug) in the engine block, with the heating
element immersed in coolant.The power cord
must be secured in its retainer clips, and not
positioned so it could contact linkages or
exhaust manifolds and become damaged.
If unit does not operate, trouble can be in either
the power cord or the heater element. Test power
cord for continuity with a 110-volt voltmeter or 110-
volt test light; test heater element continuity with an
ohmmeter or 12-volt test light.
Fig. 7 Cooling System Pressure Cap
PLCOOLING 7 - 5
DESCRIPTION AND OPERATION (Continued)

(5) Impeller loose or damaged.
(6) Sprocket or sprocket flange loose or damaged.
ACCESSORY DRIVE BELT INSPECTION
Belt replacement under any or all of the following
conditions is required, excessive wear, frayed cords or
severe glazing.
Poly-V-Belt system may develop minor cracks
across the ribbed side. These minor cracks are con-
sidered normal and acceptable. Cracks parallel are
not (Fig. 28).
NOTE: Do not use any type of belt dressing or
restorer on Poly-V-Belts.
COOLING SYSTEM CAP
Hold the cap in your hand,right side up(Fig. 29).
The vent valve at the bottom of the cap should open
with a slight pull. If the rubber gasket has swollen,
preventing the valve from opening, replace the cap.
If any light can be seen between vent valve and
the rubber gasket, replace the cap.Use only a
replacement cap that has a spring to hold the
vent shut.
A replacement cap must be of the type designed for
coolant reserve systems. This design ensures system
pressurization.
CLEANING COOLING SYSTEM
Drain cooling system (see:Draining Cooling Sys-
tem) and refill with clean water (see:Refilling
Fig. 26 Power Steering Pump Adjustment
BELT TENSION CHART
ACCESSORY
DRIVE BELTGAUGE TORQUE
Power Steering
Pump and A/C
CompressorNew 135 lb. 121 N´m (90 ft.
lbs.)
Used 100 lb. 81 N´m 60 ft.
lbs.)
Generator New 135 lb. Gauge
adjustment
method only Used 100 lb.
Fig. 27 Generator Adjustment
Fig. 28 Drive Belt Wear Pattern
7 - 22 COOLINGPL
CLEANING AND INSPECTION (Continued)

Cooling System). Run engine with radiator cap
installed until upper radiator hose is hot. Stop
engine and drain water from system. If water is
dirty, fill, run and drain system again until water
runs clear.
RADIATOR FLUSHING
Drain cooling system and remove radiator hoses
from engine. Install suitable flushing gun in radiator
lower hose. Fill radiator with clean water and turn
on air in short blasts.
CAUTION: Internal radiator pressure must not
exceed 138 kPa (20 psi) as damage to radiator may
result. Continue this procedure until water runs
clear.
ENGINE FLUSHING
Drain radiator (see:Cooling System Draining)
and remove hoses from radiator. Remove engine ther-
mostat and reinstall thermostat housing. A gasket
may be needed to seal the housing to cylinder head
because the seal is part of thermostat. Install suit-
able flushing gun to thermostat housing hose. Turn
on water, and when engine is filled, turn on air, but
no higher than 138 kPa (20 psi) in short blasts. Allowengine to fill between blasts of air. Continue this pro-
cedure until water runs clean. Install thermostat and
fill cooling system. Refer to (Cooling System Refill-
ing) for procedure.
REVERSE FLUSHING
Reverse flushing of the cooling system is the forc-
ing of water through the cooling system, using air
pressure in a direction opposite to that of the normal
flow of water. This is only necessary with dirty sys-
tems and evidence of partial plugging.
CHEMICAL CLEANING
One type of corrosion encountered with aluminum
cylinder heads is aluminum hydroxide deposits. Cor-
rosion products are carried to the radiator and depos-
ited when cooled off. They appear as dark grey when
wet and white when dry. This corrosion can be
removed with a two part cleaner (oxalic acid and
neutralizer) available in auto parts outlets. Follow
manufacturers directions for use.
ADJUSTMENTS
PROPER BELT TENSION
Satisfactory performance of the belt driven accesso-
ries depends on belt condition and proper belt ten-
sion. Refer to Accessory Drive Belt Inspection in this
section. There are two belt tensioning methods given
in order of preference:
²Belt tension gauge method.
²Torque equivalent method.
The belt tension gauge method usually requires the
vehicle to be raised on a hoist and the splash shield
removed.
TORQUE EQUIVALENT METHOD
Adjustable accessory brackets provided with a 13
mm (1/2 in.) square hole for a torque wrench can use
an equivalent torque value for belt adjustment.
Equivalent torque values for adjusting these acces-
sory drive belts are specified in the Belt Tension
Chart.
Fig. 29 Cooling System Pressure Cap
BELT TENSION CHART
ACCESSORY
DRIVE BELTGAUGE TORQUE
Power Steering
Pump and A/C
CompressorNew 135 lb. 121 N´m (90 ft.
lbs.)
Used 100 lb. 81 N´m 60 ft.
lbs.)
Generator New 135 lb. Gauge
adjustment
method only Used 100 lb.
PLCOOLING 7 - 23
CLEANING AND INSPECTION (Continued)

ENGINE
CONTENTS
page page
2.0L DOHC ENGINE...................... 58
2.0L SOHC ENGINE...................... 12ENGINE DIAGNOSIS....................... 7
STANDARD SERVICE PROCEDURES.......... 1
STANDARD SERVICE PROCEDURES
INDEX
page page
GENERAL INFORMATION
CHECKING ENGINE OIL LEVEL.............. 5
CRANKSHAFT SPROCKET BOLT ACCESS
PLUG................................ 2
ENGINE CORE PLUGS.................... 2
ENGINE OIL SERVICE..................... 5
ENGINE PERFORMANCE.................. 2FORM-IN-PLACE GASKETS................. 1
HONING CYLINDER BORES................ 3
HYDROSTATIC LOCKED ENGINE............ 4
MEASURING MAIN BEARING AND
CONNECTING ROD BEARING CLEARANCES . 3
REPAIR OF DAMAGED OR WORN THREADS . . . 4
GENERAL INFORMATION
FORM-IN-PLACE GASKETS
There are numerous places where form-in-place
gaskets are used on the engine. Care must be taken
when applying form-in-place gaskets to assure
obtaining the desired results.Do not use form-in-
place gasket material unless specified.Bead size,
continuity, and location are of great importance. Too
thin a bead can result in leakage while too much can
result in spill-over which can break off and obstruct
fluid feed lines. A continuous bead of the proper
width is essential to obtain a leak-free gasket.
There are numerous types of form-in-place gasket
materials that are used in the engine area. Mopart
Silicone Rubber Adhesive Sealant and MopartGas-
ket Maker gasket materials, each have different
properties and can not be used in place of the other.
MOPARtSILICONE RUBBER ADHESIVE
SEALANT
MopartSilicone Rubber Adhesive Sealant or equiv-
alent, normally black in color, is available in three
ounce tubes. Moisture in the air causes the Mopart
Silicone Rubber Adhesive Sealant material to cure.
This material is normally used on flexible metal
flanges. It has a shelf life of one year and will not
properly cure if over age. Always inspect the package
for the expiration date before use.MOPARtGASKET MAKER
MopartGasket Maker is an anaerobic type gasket
material. The material cures in the absence of air
when squeezed between two metallic surfaces. It will
not cure if left in the uncovered tube. The anaerobic
material is for use between two machined surfaces.
Do not use on flexible metal flanges.
MOPARtTORQUE CURE GASKET MAKER
MopartTorque Cure Gasket Maker is a unique
anaerobic type gasket material to be usedONLY
between the bedplate and engine block. The material
cures in the absence of air when torqued between
two metallic surfaces. It will not cure if left in the
uncovered tube. This anaerobic material is specially
made to seal the area between the bedplate and cyl-
inder block without disturbing the bearing clearance
or alignment of these components.
GASKET DISASSEMBLY
Parts assembled with form-in-place gaskets may be
disassembled without unusual effort. In some
instances, it may be necessary to lightly tap the part
with a mallet or other suitable tool to break the seal
between the mating surfaces. A flat gasket scraper
may also be lightly tapped into the joint but care
must be taken not to damage the mating surfaces.
SURFACE PREPARATION
Scrape clean or wire brush all gasket surfaces
removing all loose material. Inspect stamped parts to
PLENGINE 9 - 1

(2) Remove negative battery cable.
(3) Place a shop towel around the spark plugs
when removing them from the engine. This will catch
any fluid that may possibly be in the cylinder under
pressure.
(4) With all spark plugs removed, rotate engine
crankshaft using a breaker bar and socket.
(5) Identify the fluid in the cylinder(s) (i.e., cool-
ant, fuel, oil or other).
(6) Make sure all fluid has been removed from the
cylinders. Inspect engine for damage (i.e., Connecting
Rods, Pistons, Valves etc.)
(7) Repair engine or components as necessary to
prevent this problem from occurring again.
CAUTION: Squirt approximately 1 teaspoon of oil
into cylinders, rotate engine to lubricate the cylin-
der walls to prevent damage on restart.
(8) Install new spark plugs.
(9) Drain engine oil and remove oil filter.
(10) Fill engine with specified amount of approved
oil and install new oil filter.
(11) Connect negative battery cable.
(12) Start engine and check for any leaks.
CHECKING ENGINE OIL LEVEL
The best time to check engine oil level is after it
has sat overnight, or if the engine has been running,
allow the engine to be shut off for at least 5 minutes
before checking oil level.
Checking the oil while the vehicle is on level
ground will improve the accuracy of the oil level
reading. Add only when the level is at or below the
ADD mark (Fig. 5).
ENGINE OIL SERVICE
WARNING: NEW OR USED ENGINE OIL CAN BE
IRRITATING TO THE SKIN. AVOID PROLONGED OR
REPEATED SKIN CONTACT WITH ENGINE OIL.
CONTAMINANTS IN USED ENGINE OIL, CAUSED BY
INTERNAL COMBUSTION, CAN BE HAZARDOUS TO
YOUR HEALTH. THOROUGHLY WASH EXPOSED
SKIN WITH SOAP AND WATER. DO NOT WASH
SKIN WITH GASOLINE, DIESEL FUEL, THINNER, OR
SOLVENTS, HEALTH PROBLEMS CAN RESULT. DO
NOT POLLUTE, DISPOSE OF USED ENGINE OIL
PROPERLY. CONTACT YOUR DEALER OR GOVERN-MENT AGENCY FOR LOCATION OF COLLECTION
CENTER IN YOUR AREA.
ENGINE OIL SPECIFICATION
CAUTION: Do not use non-detergent or straight
mineral oil when adding or changing crankcase
lubricant. Engine failure can result.
API SERVICE GRADE CERTIFIED
Use an engine oil that is API Service Grade Certi-
fied. MOPARtprovides engine oils that conforms to
this service grade.
SAE VISCOSITY
An SAE viscosity grade is used to specify the vis-
cosity of engine oil. Use only, engine oils with multi-
ple viscosities such as 5W-30 or 10W-30. These are
specified with a dual SAE viscosity grade which indi-
cates the cold-to-hot temperature viscosity range.
Select an engine oil that is best suited to your par-
ticular temperature range and variation (Fig. 6).
ENERGY CONSERVING OIL
An Energy Conserving type oil is recommended for
gasoline engines. They are designated as either
ENERGY CONSERVING or ENERGY CONSERV-
ING II.
CONTAINER IDENTIFICATION
Standard engine oil identification notations have
been adopted to aid in the proper selection of engine
oil. The identifying notations are located on the label
of engine oil plastic bottles and the top of engine oil
cans (Fig. 7).
ENGINE OIL CHANGE
Change engine oil at mileage and time intervals
described in the Maintenance Schedule.
TO CHANGE ENGINE OIL
Run engine until achieving normal operating tem-
perature.
Fig. 5 Oil Level
Fig. 6 Temperature/Engine Oil Viscosity
PLENGINE 9 - 5
GENERAL INFORMATION (Continued)

(1) Position the vehicle on a level surface and turn
engine off.
(2) Hoist and support vehicle on safety stands.
Refer to Hoisting and Jacking Recommendations.(3) Remove oil fill cap.
(4) Place a suitable drain pan under crankcase
drain.
(5) Remove drain plug from crankcase and allow
oil to drain into pan. Inspect drain plug threads for
stretching or other damage. Replace drain plug and
gasket if damaged.
(6) Install drain plug in crankcase.
(7) Lower vehicle and fill crankcase with specified
type and amount of engine oil described in this sec-
tion.
(8) Install oil fill cap.
(9) Start engine and inspect for leaks.
(10) Stop engine and inspect oil level.
Fig. 7 Engine Oil Container Standard Notations
9 - 6 ENGINEPL
GENERAL INFORMATION (Continued)

incorporates main bearing caps. Rear seal retainer is
integral with the block.
CRANKSHAFTA nodular cast iron crankshaft is
used. The engine has 5 main bearings, with number
3 flanged to control thrust. The 52 mm diameter
main and 48 mm diameter crank pin journals (all)
have undercut fillet radiuses that are deep rolled for
added strength. To optimize bearing loading 8 coun-
terweights are used. Hydrodynamic seals provide end
sealing, where the crankshaft exits the block.
Anaerobic gasket material is used for parting line
sealing. A sintered iron timing belt sprocket is
mounted on the crankshaft nose. This sprocket pro-
vides motive power; via timing belt to the camshaft
sprocket providing timed valve actuation.
PISTONSThe DOHC EngineDO NOThave pro-
vision for a free wheeling valve train. Non free
wheeling valve train means, in the event of a broken
timing belt Pistons will contact the Valves. All
engines use pressed-in piston pins to attach forged
powdered metal connecting rods. The connecting rods
are a cracked cap design and are not repairable. Hex
head cap screw are used to provide alignment and
durability in the assembly.
PISTON RINGSThe piston rings include a
molybdenum faced top ring for reliable compression
sealing and a taper faced intermediate ring for addi-
tional cylinder pressure control. Oil Control Ring
Package contains of 2 steel rails and a expander
spacer.
CYLINDER HEADFeatures a Dual Over Head
Camshaft (DOHC), 4 valves per cylinder cross flow
design. The valves are arranged in two in-line banks,
with the ports of the bank of two intake valves per
cylinder facing toward the radiator side of engine
and ports of the bank of two exhaust valves per cyl-
inder facing toward the dash panel. Incorporates
powder metal valve guides and seats. Integral oil gal-
leys within the cylinder head supplies oil to the
hydraulic lash adjusters, camshaft and valve mecha-
nisms.
CAMSHAFTSThe nodular iron camshafts have
six bearing journals and 2 cam lobes per cylinder.
Flanges at the rear journals control camshaft end
play. Provision for cam position sensor is located on
the intake camshaft at the rear of cylinder head. A
hydrodynamic oil seal is used for oil control at the
front of the camshaft.
VA LV E SFour valves per cylinder are actuated by
roller cam followers which pivot on stationary
hydraulic lash adjusters. All valves have 6 mm diam-
eter chrome plated valve stems. The valve sizes are
34.8 mm (1.370 inch.) diameter intake valves and
30.5 mm (1.20 inch.) diameter exhaust valves. Viton
rubber valve stem seals are integral with the springseats. Valve springs, spring retainers, and locks are
conventional.
INTAKE MANIFOLDThe intake manifold is a
two piece aluminum casting, attached to the cylinder
head with ten fasteners. This long branch fan design
enhances low and mid-speed torque.
EXHAUST MANIFOLDThe exhaust manifold is
made of nodular cast iron for strength and high tem-
peratures. Exhaust gasses exit through a machined,
articulated joint connection to the exhaust pipe.
COMPONENT REPLACEMENT
If any of the following parts have been changed or
replaced:
²Camshaft
²Camshaft Position Sensor
²Camshaft Position Sensor Target Magnet
²Cylinder Block
²Cylinder Head
²Water Pump
²Powertrain Control Module (PCM)
²Timing Belt and Timing Belt Tensioner
The camshaft and crankshaft timing relearn proce-
dure must be performed. Refer to the component
Removal and Installation procedure outlined in this
Group.
DIAGNOSIS AND TESTING
CHECKING ENGINE OIL PRESSURE
(1) Remove oil pressure switch and install gauge
assembly C-3292 with adaptor.
(2) Run engine until thermostat opens.
CAUTION: If oil pressure is 0 at idle, Do Not per-
form the 3000 RPM test in the next step.
(3) Oil Pressure:Curb Idle25 kPa (4 psi) mini-
mum3000 RPM170-550 kPa (25-80 psi).
(4) If oil pressure is 0 at idle. Shut off engine,
check for pressure relief valve stuck open, a clogged
oil pick-up screen or a damaged oil pick-up tube
O-ring.
SERVICE PROCEDURES
CYLINDER BORE AND PISTON SIZING
The cylinder walls should be checked for out-of-
round and taper with Tool C-119 (Fig. 4). The cylin-
der bore out-of-round is 0.050 mm (.002 inch)
maximum and cylinder bore taper is 0.051 mm (0.002
inch) maximum. If the cylinder walls are badly
scuffed or scored, the cylinder block should be
rebored and honed, and new pistons and rings fitted.
Whatever type of boring equipment is used, boring
and honing operation should be closely coordinated
9 - 60 2.0L DOHC ENGINEPL
DESCRIPTION AND OPERATION (Continued)

FUEL SYSTEM
CONTENTS
page page
FUEL DELIVERY SYSTEM................... 3
FUEL INJECTION SYSTEM................. 20GENERAL INFORMATION................... 1
GENERAL INFORMATION
INDEX
page page
GENERAL INFORMATION
FUEL REQUIREMENTS.................... 1
GASOLINE/OXYGENATE BLENDS............ 1INTRODUCTION......................... 1
PCM REPLACEMENT..................... 1
GENERAL INFORMATION
INTRODUCTION
Throughout this group, references may be made to
a particular vehicle by letter or number designation.
A chart showing the breakdown of these designations
is included in the Introduction Section at the front of
this service manual.
The Evaporation Control System, is also considered
part of the fuel system. The system reduces the emis-
sion of fuel vapor into the atmosphere.
The description and function of the Evaporation
Control System is found in Group 25 of this manual.
PCM REPLACEMENT
USE THE DRB SCAN TOOL TO REPROGRAM
THE NEW PCM WITH THE VEHICLES ORIGI-
NAL IDENTIFICATION NUMBER (VIN) AND
THE VEHICLES ORIGINAL MILEAGE. IF THIS
STEP IS NOT DONE A DIAGNOSTIC TROUBLE
CODE (DTC) MAY BE SET.
FUEL REQUIREMENTS
Your vehicle was designed to meet all emission reg-
ulations and provide excellent fuel economy when
using high quality unleaded gasoline.
Use unleaded gasolines having a minimum posted
octane of 87.
If your vehicle develops occasional light spark
knock (ping) at low engine speeds this is not harm-
ful. However; continued heavy knock at high speeds
can cause damage and should be reported to yourdealer immediately. Engine damage as a result of
heavy knock operation may not be covered by the
new vehicle warranty.
In addition to using unleaded gasoline with the
proper octane rating, those that contain detergents,
corrosion and stability additives are recommended.
Using gasolines that have these additives will help
improve fuel economy, reduce emissions, and main-
tain vehicle performance.
Poor quality gasoline can cause problems such as
hard starting, stalling, and stumble. If you experi-
ence these problems, try another brand of gasoline
before considering service for the vehicle.
GASOLINE/OXYGENATE BLENDS
Some fuel suppliers blend unleaded gasoline with
materials that contain oxygen such as alcohol, MTBE
(Methyl Tertiary Butyl Ether) and ETBE (Ethyl Ter-
tiary Butyl Ether). Oxygenates are required in some
areas of the country during winter months to reduce
carbon monoxide emissions. The type and amount of
oxygenate used in the blend is important.
The following are generally used in gasoline
blends:
Ethanol- (Ethyl or Grain Alcohol) properly
blended, is used as a mixture of 10 percent ethanol
and 90 percent gasoline. Gasoline blended with etha-
nol may be used in your vehicle.
MTBE/ETBE- Gasoline and MTBE (Methyl Ter-
tiary Butyl Ether) blends are a mixture of unleaded
gasoline and up to 15 percent MTBE. Gasoline and
ETBE (Ethyl Tertiary Butyl Ether) are blends of gas-
PLFUEL SYSTEM 14 - 1

ELECTRIC FUEL PUMP
The electric fuel pump is located in and is part of
the fuel pump module. It is a positive displacement,
gerotor type, immersible pump with a permanent
magnet electric motor. The fuel pump module is sus-
pended in fuel in the fuel tank. The pump draws fuel
through a strainer and pushes it through the motor
to the outlet. The pump contains a check valve. The
valve, in the pump outlet, maintains pump pressure
during engine off conditions. The fuel pump relay
provides voltage to the fuel pump.
The fuel pump has a maximum deadheaded pres-
sure output of approximately 880 kPa (130 psi). The
regulator adjusts fuel system pressure to approxi-
mately 338 kPa (49 psi).
FUEL GAUGE SENDING UNIT
The fuel gauge sending unit (fuel level sensor) is
attached to the side of the fuel pump module. The
sending unit consists of a float, an arm, and a vari-
able resistor (track). The resistor track is used to
send electrical signals to the Powertrain Control
Module (PCM) for fuel gauge operation and for OBD
II emission requirements.
For fuel gauge operation:As fuel level
increases, the float and arm move up. This decreases
the sending unit resistance, causing the fuel gauge to
read full. As fuel level decreases, the float and arm
move down. This increases the sending unit resis-
tance causing the fuel gauge to read empty.
After this fuel level signal is sent to the PCM, the
PCM will transmit the data across the CCD bus cir-
cuits to the instrument panel. Here it is translated
into the appropriate fuel gauge level reading.
FUEL FILTER/FUEL PRESSURE REGULATOR
A combination fuel filter and fuel pressure regula-
tor is used on all gas powered engines. It is located
on the top of the fuel pump module. A separate frame
mounted fuel filter is not used.
Fuel Pressure Regulator Operation:The pres-
sure regulator is a mechanical device that is cali-
brated to maintain fuel system operating pressure of
approximately 338 kPa (49 psi) at the fuel injectors.
It contains a diaphragm, calibrated springs and a
fuel return valve. The internal fuel filter (Fig. 2) is
also part of the assembly.
Fuel is supplied to the filter/regulator by the elec-
tric fuel pump through an opening tube at the bot-
tom of filter/regulator.
The fuel pump module contains a check valve to
maintain some fuel pressure when the engine is not
operating. This will help to start the engine.
If fuel pressure at the pressure regulator exceeds
approximately 49 psi, an internal diaphragm closes
and excess fuel pressure is routed back into the tankthrough the pressure regulator. A separate fuel
return line is not used with any gas powered engine.
FUEL TANK
All models pass a full 360 degree rollover test
without fuel leakage. To accomplish this, fuel and
vapor flow controls are required for all fuel tank con-
nections.
All models are equipped with either one or two
rollover valves mounted into the top of the fuel tank
(or pump module). Refer to Group 25, Emission Con-
trol System for rollover valve information.
An evaporation control system is connected to the
rollover valve(s) to reduce emissions of fuel vapors
into the atmosphere. When fuel evaporates from the
fuel tank, vapors pass through vent hoses or tubes to
a charcoal canister where they are temporarily held.
When the engine is running, the vapors are drawn
into the intake manifold. Certain models are also
equipped with a self-diagnosing system using a Leak
Detection Pump (LDP). Refer to Group 25, Emission
Control System for additional information.
FUEL RAIL
The fuel rail supplies the necessary fuel to each
individual fuel injector and is mounted to the intake
manifold (Fig. 3). The fuel pressure regulator is no
longer mounted to the fuel rail on any engine. It is
now located on the fuel tank mounted fuel pump
module. Refer to Fuel Filter/Fuel Pressure Regulator
in the Fuel Delivery System section of this group for
information. The fuel rail is not repairable.
Fig. 2 Side ViewÐFilter/Regulator
14 - 4 FUEL SYSTEMPL
DESCRIPTION AND OPERATION (Continued)