check engine DODGE NEON 1999 Service Repair Manual

(8) Install main bearing bedplate to engine block
bolts (1 ± 10) and torque each bolt to 81 N´m (60 ft.
lbs.) in sequence shown in (Fig. 79).
(9) Install main bearing bedplate to engine block
bolts (11 ± 20), with baffle studs in positions 12, 13
and 16 and torque each bolt to 30 N´m (22 ft. lbs.) in
sequence shown in (Fig. 79).
(10) After the main bearing bedplate is installed,
check the crankshaft turning torque. The turning
torque should not exceed 5.6 N´m (50 in. lbs.).
(11) Install oil pump. If crankshaft end play is to
be checked refer to service procedures in this section.
(12) Install crankshaft sprocket.
(13) Install oil filter adapter and filter.
(14) Install oil pan and structural collar. Refer to
procedures outlined in the section.
(15) Perform camshaft and crankshaft timing
relearn procedure as follows:
²Connect the DRB scan tool to the data link
(diagnostic) connector. This connector is located in
the passenger compartment; at the lower edge of
instrument panel; near the steering column.
²Turn the ignition switch on and access the ªmis-
cellaneousº screen.
²Select ªre-learn cam/crankº option and follow
directions on DRB screen.
OIL FILTER ADAPTER
REMOVE AND INSTALL
Ensure O-ring is in the groove on adapter. Align
roll pin into engine block and tighten assembly to 80
N´m (60 ft. lbs.) (Fig. 80).
OIL FILTER
REMOVE AND INSTALL
CAUTION: When servicing the oil filter (Fig. 81)
avoid deforming the filter, install tool band strap
against the seam at the base of the filter. The seam,
joining the can to the base is reinforced by the
base plate.
(1) Turn counterclockwise to remove.
(2) To install, lubricate new filter gasket. Check
filter mounting surface. The surface must be smooth,
flat and free of debris or old pieces of rubber. Screw
filter on until gasket contacts base. Tighten to 21
N´m (15 ft. lbs.).
Fig. 79 Main Bearing Caps/Bedplate Torque
Sequence
Fig. 80 Engine Oil Filter Adapter to Engine Block
Fig. 81 Engine Oil Filter
PL2.0L DOHC ENGINE 9 - 87
REMOVAL AND INSTALLATION (Continued)

Chart for specifications. Replace guides if they are
not within specification.
CHECK VALVE GUIDE HEIGHT
TESTING VALVE SPRINGS
(1) Whenever valves have been removed for inspec-
tion, reconditioning or replacement, valve springs
should be tested Special Tool C-647. As an example,
the compression length of the spring to be tested is
33.34 mm (1-5/16 inches). Turn tool table until sur-
face is in line with the 33.34 mm (1-5/16 inch) mark
on the threaded stud and the zero mark on the front.
Place spring over stud on the table and lift compress-
ing lever to set tone device (Fig. 97). Pull on torque
wrench until ping is heard. Take reading on torque
wrench at this instant. Multiply this reading by two.This will give the spring load at test length. Frac-
tional measurements are indicated on the table for
finer adjustments. Discard the springs that do not
meet specifications. The Following specifications
apply to both intake and exhaust valve springs:
²Valve Closed Compression Pressure: 246 ± 270 N
@ 38.0 mm (55 ± 60 lbs. @ 1.50 in.)
²Valve Open Compression Pressure: 549 ± 611 N
@ 29.25 mm (123 ± 137 lbs. @ 1.17 in.)
(2) Verify springs are not distorted with a steel
square and surface plate. Check springs from both
ends. Replace spring if the spring is more than 1.5
mm (1/16 inch) out of square.
REFACING VALVES AND VALVE SEATS
(1) The intake and exhaust valve seats and valve
face have a 45 and a 45 1/2 degree angles.
(2) Inspect the remaining margin after the valves
are refaced (Fig. 98). Intake valves with less than 1.2
mm (3/64 inch.) margin and Exhaust valves with less
than 0.9 mm (1/32 inch.) margin should be discarded.
(3) When refacing valve seats, it is important that
the correct size valve guide pilot be used for the
reseating stones. A true and complete surface must
be obtained.
(4) Measure the concentricity of valve seat and
valve guide using a valve seat runout dial indicator.
Total runout should not exceed. 0.051 mm (0.002
inch.) (total indicator reading).
(5) Inspect the valve seat with Prussian blue to
determine where the valve contacts the seat. To do
this, coat valve seatLIGHTLYwith Prussian blue
then set valve in place. Rotate the valve with light
pressure. If the blue is transferred to the center of
valve face, contact is satisfactory. If the blue is trans-
ferred to top edge of the valve face, lower valve seat
with a 15 degrees stone. If the blue is transferred to
the bottom edge of valve face raise valve seat with a
65 degrees stone.
Fig. 96 Checking Wear on Valve GuideÐTypical
VALVE GUIDE SPECIFICATION CHART
Valve Guide
DiameterIntake Valve Exhaust Valve
5.975 - 6.000 mm
(0.2352 - 0.2362
in.)5.975 - 6.000 mm
(0.2352 - 0.2362
in.)
Valve Guide
ClearanceIntake Valve Exhaust Valve
New: 0.023 - 0.066 mm
(0.001 - 0.0025
in.)0.051 - 0.094 mm
(0.002 - 0.0037
in.)
Service Limit: 0.25 mm (0.010 in.)
Valve Guide Height
Fig. 97 Testing Valve Spring
9 - 92 2.0L DOHC ENGINEPL
DISASSEMBLY AND ASSEMBLY (Continued)

²Intake valve seat diameter is 34.37 - 34.63 mm
(1.353 - 1.363 inch.)
²Exhaust valve seat diameter is 29.37 29.63 mm
(1.156 1.166 inch.)
(6)
Valve seats which are worn or burned can be
reworked, provided that correct angle and seat width
are maintained. The intake valve seat must be serviced
when the valve seat width is 2.0 mm (0.079 in.) or
greater. The exhaust valve seat must be serviced when
the valve seat width is 2.5 mm (0.098 in.) or greater.
Otherwise the cylinder head must be replaced. For spec-
ification refer to Valve Specification Chart.
(7) When seat is properly positioned the width of
intake and exhaust seats should be 0.90 to 1.30 mm
(0.035 to 0.051 inch.) (Fig. 99).
(8) Check valve tip height dimensions A after
grinding the valve seats or faces (Fig. 100). Grind
valve tip to 47.99 mm (1.889 in.) for exhaust valve
and 48.04 mm (1.891 in.) for intake valve when
installed in the head (Fig. 100). The valve tip cham-
fer may need to be reground to prevent seal damage
when the valve is installed.
VALVE INSTALLATION
(1) Coat valve stems with clean engine oil and
insert in cylinder head.
(2) Install new valve stem seals on all valves using
a valve stem seal tool (Fig. 101). The valve stem
seals should be pushed firmly and squarely over
valve guide.
VALVE SPECIFICATION CHART
Face Angle
Intake and
Exhaust:45 - 44 1/2É
Head Diameter
Intake: 34.67 - 34.93 mm (1.364 - 1.375 in.)
Exhaust: 30.37 - 30.63 mm (1.195 - 1.205 in.)
Length (Overall)
Intake: 111.49 - 111.99 mm (4.389 - 4.409 in.)
Exhaust: 109.59 - 110.09 mm (4.314 - 4.334 in)
Stem Diameter
Intake: 5.934 - 5.952 mm (0.2337 - 0.2344 in)
Exhaust: 5.906 - 5.924 mm (0.2326 - 0.2333 in.)
Valve Margin
Intake: 1.285 - 1.615 mm (0.050 - 0.063 in.)
Exhaust: 0.985 - 1.315 mm (0.038 - 0.051 in.)
Fig. 98 Refacing Intake and Exhaust Valves
Fig. 99 Refacing Valve Seats
Fig. 100 Checking Spring Installed Height and Valve
Tip Height Dimensions
PL2.0L DOHC ENGINE 9 - 93
DISASSEMBLY AND ASSEMBLY (Continued)

CAUTION: If oversize valves are used, there is only
one oversize valve available. The same stem seal is
used on both the standard and oversize valve.
(3) Install valve springs and retainers. Compress
valve springs only enough to install locks, taking
care not to misalign the direction of compression.
Nicked valve stems may result from misalignment of
the valve spring compressor.
CAUTION: When depressing the valve spring
retainers with valve spring compressor the locks
can become dislocated. Check to make sure both
locks are in their correct location after removing
tool.
(4) Check the valve spring installed height B after
refacing the valve and seat (Fig. 100). Make sure
measurements are taken from top of spring seat to
the bottom surface of spring retainer. If height is
greater than 38.75 mm (1.525 in.), install a 7.620
mm (0.030 inch.) spacer under the valve spring seat
to bring spring height back within specification.
(5) Install cam followers and camshaft as previ-
ously described in this section.
(6) Checking dry lash. Dry lash is the amount of
clearance that exists between the base circle of an
installed cam and the rocker arm roller when the
adjuster is drained of oil and completely collapsed.
Specified dry lash is 1.17 mm (0.046 in.) for intake
and 1.28 mm (0.050 in.) for exhaust. After performing
dry lash check, refill adjuster with oil and allow 10
minutes for adjuster or adjusters to bleed down
before rotating cam.
CLEANING AND INSPECTION
CYLINDER HEAD AND CAMSHAFT JOURNALS
INSPECTING CYLINDER HEAD
Cylinder head must be flat within 0.1 mm (0.004
inch) (Fig. 102).Inspect cylinder head camshaft bearings for wear.
Check camshaft journals for scratches and worn
areas. If light scratches are present, they may be
removed with 400 grit sand paper. If deep scratches
are present, replace the camshaft and check the cyl-
inder head for damage. Replace the cylinder head if
worn or damaged. Check the lobes for pitting and
wear. If the lobes show signs of wear, check the cor-
responding rocker arm roller for wear or damage.
Replace rocker arm/hydraulic lash adjuster if worn or
damaged. If lobes show signs of pitting on the nose,
flank or base circle; replace the camshaft.
CLEANING
Remove all gasket material from cylinder head and
block. Be careful not to gouge or scratch the alumi-
num head sealing surface.
OIL PUMP
(1) Clean all parts thoroughly. Mating surface of
the oil pump should be smooth. Replace pump cover
if scratched or grooved.
(2) Lay a straightedge across the pump cover sur-
face (Fig. 103). If a 0.076 mm (0.003 inch.) feeler
gauge can be inserted between cover and straight
edge, cover should be replaced.
(3) Measure thickness and diameter of outer rotor.
If outer rotor thickness measures 7.64 mm (0.301
inch.) or less (Fig. 104), or if the diameter is 79.95
mm (3.148 inches) or less, replace outer rotor.
(4) If inner rotor measures 7.64 mm (.301 inch) or
less replace inner rotor (Fig. 105).
(5) Slide outer rotor into pump housing, press to
one side with fingers and measure clearance between
rotor and housing (Fig. 106). If measurement is 0.39
mm (0.015 inch.) or more, replace housing only if
outer rotor is in specification.
Fig. 101 Valve Stem Oil Seal ToolFig. 102 Checking Cylinder Head Flatness
9 - 94 2.0L DOHC ENGINEPL
DISASSEMBLY AND ASSEMBLY (Continued)

(6) Install inner rotor into pump housing. If clear-
ance between inner and outer rotors (Fig. 107) is .203
mm (.008 inch) or more, replace both rotors.(7) Place a straightedge across the face of the
pump housing, between bolt holes. If a feeler gauge
of .102 mm (.004 inch) or more can be inserted
between rotors and the straightedge, replace pump
assembly (Fig. 108).ONLYif rotors are in specs.
(8) Inspect oil pressure relief valve plunger for
scoring and free operation in its bore. Small marks
may be removed with 400-grit wet or dry sandpaper.
(9) The relief valve spring has a free length of
approximately 60.7 mm (2.39 inches) it should test
between 18 and 19 pounds when compressed to 40.5
mm (1.60 inches). Replace spring that fails to meet
specifications.
(10) If oil pressure is low and pump is within spec-
ifications, inspect for worn engine bearings, damaged
or missing oil pick-up tube o-ring, clogged oil pick-up
tube screen, clogged oil filter and stuck open pres-
sure relief valve or other reasons for oil pressure
loss.
Fig. 103 Checking Oil Pump Cover Flatness
Fig. 104 Measuring Outer Rotor Thickness
Fig. 105 Measuring Inner Rotor Thickness
Fig. 106 Measuring Outer Rotor Clearance in
Housing
Fig. 107 Measuring Clearance Between Rotors
PL2.0L DOHC ENGINE 9 - 95
CLEANING AND INSPECTION (Continued)

CYLINDER BLOCK AND BORE
(1) Clean cylinder block thoroughly and check all
core hole plugs for evidence of leaking.
(2) If new core plugs are installed, Refer to Engine
Core Plugs outlined in this section.
(3) Examine block and cylinder bores for cracks or
fractures.
CYLINDER BORE INSPECTION
The cylinder walls should be checked for out-of-
round and taper with Tool C-119 (Fig. 109). The cyl-
inder 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
with the fitting of pistons and rings in order that
specified clearances may be maintained.Refer to
Honing Cylinder Bores outlined in the Stan-
dard Service Procedures for specification and
procedures.
Measure the cylinder bore at three levels in direc-
tions A and B (Fig. 109). Top measurement should be
10 mm (3/8 inch) down and bottom measurement
should be 10 mm (3/8 inch.) up from bottom of bore.
Refer to Cylinder Bore and Piston Specification
Chart for specifications.
SPECIFICATIONS
2.0L DOHC
Cylinder Block
Cylinder Bore Diameter. . . .87.4924 - 87.5076 mm
(3.4446 - 3.4452 in.)
Out-of-Round (Max.)........0.051 mm (0.002 in.)
Taper (Max.)..............0.051 mm (0.002 in.)
Pistons
Clearance 17.5 mm (11/16 in.) from bottom of
skirt......0.018 - 0.050 mm (0.0007 - 0.0020 in.)
Weight........340 - 350 grams (11.99 - 12.34 oz.)
Head Land Clearance (Diametrical) . .0.740 - 0.803
mm (0.029 - 0.031 in.)
Piston Length..............64.8 mm (2.551 in.)
Piston Ring Groove Depth No. 1 .3.983 - 4.132 mm
(0.157 - 0.163 in.)
Fig. 108 Measuring Clearance Over Rotors
Fig. 109 Checking Cylinder Bore Size
CYLINDER BORE AND PISTON
SPECIFICATION CHART
Standard Bore Max. Out-of-
RoundMax. Taper
87.5 mm (3.445
in.)0.051 mm
(0.002 in.)0.051 mm
(0.002 in.)
Standard Piston Size
87.463 - 87.481 mm (3.4434 - 3.4441 in.)
Piston to Bore Clearance
0.012 - 0.044 mm (0.0005 - 0.0017 in.)
Measurements taken at Piston Size Location.
9 - 96 2.0L DOHC ENGINEPL
CLEANING AND INSPECTION (Continued)

NOTE: When replacement is required on any com-
ponent of the exhaust system, you must use origi-
nal equipment parts (or their equivalent).
INSTALLATION
When assembling exhaust systemdo nottighten
clamps until components are aligned and clearances
are checked.
(1) Assemble catalytic convertor to exhaust mani-
fold connection. Use a new flange gasket (LEV only)
(Fig. 9) or (Fig. 10).
(2) Assemble exhaust pipe to catalytic convertor
and the support to the underbody
(3) Install the muffler to exhaust pipe and the sup-
ports to the underbody.
(4) Working from the front of system;
(5) Align and tighten the catalytic convertor to
exhaust manifold ball joint bolts to 27 N´m (20 ft.
lbs.) (Fig. 9) or flex-joint attaching nuts (LEV) to 28
N´m (250 in. lbs.).
(6) Align each component to maintain position and
proper clearance with underbody parts (Fig. 11) and
tighten band clamps to specifications (Fig. 12).
CAUTION: Band (Torca) clamps should never be
tighten such that the two sides of the clamps are
bottomed out against the center hourglass shaped
center block. Once this occurs, the clamp has lost
its clamping force and must be replaced.
(7) Connect the downstream heated oxygen sensor
and lower the vehicle.
INTAKE MANIFOLDÐSOHC ENGINE
REMOVAL
WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE SERVICING FUEL SYSTEM COMPONENTS.
SERVICE VEHICLES IN WELL VENTILATED AREAS
AND AVOID IGNITION SOURCES. NEVER SMOKE
WHILE SERVICING THE VEHICLE.
(1) Disconnect negative cable from battery.
(2) Remove fuel filler cap.
(3) Remove the fresh air inlet duct from air
cleaner (Fig. 15).
(4) Remove the protective cap from the fuel pres-
sure test port on the fuel rail (Fig. 13).
(5) Place the open end of fuel pressure release
hose, Special Tool C-4799-1, into an approved gaso-
line container. Connect the other end of hose to the
fuel pressure test port (Fig. 14). Fuel pressure will
bleed off through the hose into the gasoline con-
tainer. Fuel gauge C-4799-A contains hose C-4799-1.
(6) Perform fuel system pressure release procedure
before attempting any repairs.
(7) Disconnect the fuel supply line quick connect at
the fuel tube assembly.
Fig. 11 Exhaust Clearance
Fig. 12 Band Clamp (Torca)
Fig. 13 Fuel Pressure Test Port
11 - 6 EXHAUST SYSTEM AND INTAKE MANIFOLDPL
REMOVAL AND INSTALLATION (Continued)

INSTALLATION
Before installing manifold. Clean all mating sur-
faces. Replace all seals, with new seals. All intakemanifold fasteners and washers are to be discarded
andNEWfasteners and washers are to be used.
(1) Install intake manifold onto cylinder head and
tighten fasteners to 12 N´m (105 in. lbs.) in sequence
shown in (Fig. 20).
(2) Install intake manifold to water inlet support.
Tighten fastener (Fig. 20) to 12 N´m (105 in. lbs.).
(3) Remove covering from fuel injector holes and
insure the holes are clean. Install fuel rail assembly
to intake manifold. Tighten screws to 23 N´m (200 in.
lbs.).
(4) Connect PCV and brake booster hoses.
(5) Inspect quick connect fittings for damage,
replace if necessary Refer to Group 14, Fuel System
for procedure. Apply a light amount of clean engine
oil to fuel inlet tube. Connect fuel supply hose to fuel
rail assembly. Check connection by pulling on connec-
tor to insure it locked into position.
(6) Install throttle body. Tighten fastener to 22
N´m (200 in. lbs.). Install transmission to throttle
body support bracket and tighten to 11.9 N´m (105
in. lbs.) at the throttle body first. Next tighten the
bracket at the transmission.
(7) Connect Manifold Absolute Pressure/Intake Air
Temperature Sensor (TMAP) wiring connector.
(8) Connect knock sensor connector, and wiring at
starter. Connect wiring harness to intake manifold
tab.
(9) Connect Idle Air Control (IAC) motor and
Throttle Position Sensor (TPS) wiring connectors.
(10) Connect vacuum hoses to throttle body.
(11) Install accelerator, kickdown and speed con-
trol cables to their bracket and connect them to the
throttle lever. Refer to Group 14, Fuel System Throt-
tle Body Installation for procedure.
(12) Loose assemble the EGR tube onto valve and
intake manifold finger tight. Tighten tube fasteners
at the EGR valve first to 11 N´m (95 in. lbs.) then,
tighten the intake manifold side fasteners to 11 N´m
(95 in. lbs.).
(13) Install clean air duct to air filter housing.
Tighten clamp to 3 N´m (30 in. lbs.).
(14) Connect negative cable to battery.
(15) Install fresh air duct to air cleaner and
tighten wing nut.
(16) With the DRB scan tool use ASD Fuel System
Test to pressurize system to check for leaks.
CAUTION: When using the ASD Fuel System Test,
the Auto Shutdown (ASD) relay will remain ener-
gized for 7 minutes or until the ignition switch is
turned to the OFF position, or Stop All Test is
selected.
Fig. 18 Knock Sensor
Fig. 19 EGR Tube Assembly
Fig. 20 Intake Manifold Tightening Sequence
11 - 8 EXHAUST SYSTEM AND INTAKE MANIFOLDPL
REMOVAL AND INSTALLATION (Continued)

INSTALLATION
Before installing manifolds. Clean all mating sur-
faces. Replace all gaskets, with new.
(1) Assemble lower manifold to upper (if sepa-
rated) and tighten bolts in sequence shown in (Fig.
29) to 28 N´m (250 in. lbs.).
(2) Install intake manifold onto cylinder head and
tighten fasteners to 28 N´m (250 in. lbs.) in sequence
shown in (Fig. 30).
(3) Remove covering from fuel injector holes and
insure the holes are clean. Install fuel rail assembly
to intake manifold. Tighten screws to 23 N´m (200 in.
lbs.).
(4) Connect PCV and brake booster hoses.
(5) Inspect quick connect fittings for damage,
replace if necessary Refer to Group 14, Fuel System
for procedure. Apply a light amount of clean engine
oil to fuel inlet tube. Connect fuel supply hose to fuel
rail assembly. Check connection by pulling on connec-
tor to insure it locked into position.
(6) Connect heater tube and hose to intake mani-
fold.
(7) Connect upper radiator hose and coolant recov-
ery hose.
(8) Connect coolant temperature sensor wiring con-
nector.
(9) Install throttle body. Tighten fastener to 22
N´m (200 in. lbs.).
(10) Connect Manifold Absolute Pressure/Intake
Air Temperature Sensor (TMAP) wiring connector.(11) Connect knock sensor connector and starter
wires. Connect wiring harness to heater tube tab.
(12) Connect Idle Air Control (IAC) motor and
Throttle Position Sensor (TPS) wiring connectors.
(13) Connect vacuum hoses to throttle body.
(14) Install accelerator, kickdown and speed con-
trol cables to their bracket and connect them to the
throttle lever. Refer to Group 14, Fuel System Throt-
tle Body Installation for procedure.
(15) Loose assemble the EGR tube onto valve and
intake manifold finger tight. Tighten tube fasteners
at the EGR valve first to 11 N´m (95 in. lbs.) then,
tighten the intake manifold side fasteners to 11 N´m
(95 in. lbs.).
(16) Install fresh air duct to air filter housing.
Tighten clamp to 3 N´m (25 in. lbs.).
(17) Connect negative cable to battery.
(18) With the DRB scan tool use ASD Fuel System
Test to pressurize system to check for leaks.
CAUTION: When using the ASD Fuel System Test,
the Auto Shutdown (ASD) relay will remain ener-
gized for 7 minutes or until the ignition switch is
turned to the OFF position, or Stop All Test is
selected.
EXHAUST MANIFOLD
REMOVAL
(1) Remove air cleaner assembly and bracket.
(2) Remove exhaust manifold heat shield (Fig. 31).
(3) Disconnect upstream heated oxygen sensor con-
nector.
Fig. 29 Lower Intake Manifold to Upper Tightening
Sequence
Fig. 30 Intake Manifold To Cylinder Head Tightening
Sequence
Fig. 31 Exhaust Manifold Heat Shield
PLEXHAUST SYSTEM AND INTAKE MANIFOLD 11 - 11
REMOVAL AND INSTALLATION (Continued)

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)