1999 DODGE NEON Timing

Plastic clips in various locations protect the cables
from damage. When the cables are replaced the clips
must be used to prevent damage to the cables. The
#1 cable must be routed under the PCV hose and
clipped to the #2 cable.
ELECTRONIC IGNITION COILS
WARNING: THE DIRECT IGNITION SYSTEM GEN-
ERATES APPROXIMATELY 40,000 VOLTS. PER-
SONAL INJURY COULD RESULT FROM CONTACT
WITH THIS SYSTEM.
The coil pack consists of 2 coils molded together.
The coil pack is mounted on the valve cover (Fig. 3)
or (Fig. 4). High tension leads route to each cylinder
from the coil. The coil fires two spark plugs every
power stroke. One plug is the cylinder under com-
pression, the other cylinder fires on the exhaust
stroke. Coil number one fires cylinders 1 and 4. Coil
number two fires cylinders 2 and 3. The PCM deter-
mines which of the coils to charge and fire at the cor-
rect time.
The Auto Shutdown (ASD) relay provides battery
voltage to the ignition coil. The PCM provides a
ground contact (circuit) for energizing the coil. When
the PCM breaks the contact, the energy in the coil
primary transfers to the secondary causing the
spark. The PCM will de-energize the ASD relay if it
does not receive the crankshaft position sensor and
camshaft position sensor inputs. Refer to Auto Shut-
down (ASD) RelayÐPCM Output, in this section for
relay operation.
AUTOMATIC SHUTDOWN RELAY
The Automatic Shutdown (ASD) relay supplies bat-
tery voltage to the fuel injectors, electronic ignition
coil and the heating elements in the oxygen sensors.
A buss bar in the Power Distribution Center (PDC)
supplies voltage to the solenoid side and contact sideof the relay. The ASD relay power circuit contains a
20 amp fuse between the buss bar in the PDC and
the relay. The fuse also protects the power circuit for
the fuel pump relay and pump. The fuse is located in
the PDC. Refer to Group 8W, Wiring Diagrams for
circuit information.
The PCM controls the ASD relay by switching the
ground path for the solenoid side of the relay on and
off. The PCM turns the ground path off when the
ignition switch is in the Off position. When the igni-
tion switch is in On or Start, the PCM monitors the
crankshaft and camshaft position sensor signals to
determine engine speed and ignition timing (coil
dwell). If the PCM does not receive crankshaft and
camshaft position sensor signals when the ignition
switch is in the Run position, it will de-energize the
ASD relay.
The ASD relay is located in the PDC (Fig. 5). The
inside top of the PDC cover has label showing relay
and fuse identification.
Fig. 3 Ignition Coil PackÐSOHC
Fig. 4 Ignition Coil PackÐDOHC
Fig. 5 Power Distribution Center (PDC)
PLIGNITION SYSTEM 8D - 3
DESCRIPTION AND OPERATION (Continued)

CRANKSHAFT POSITION SENSOR
The PCM determines what cylinder to fire from the
crankshaft position sensor input and the camshaft
position sensor input. The second crankshaft counter-
weight has machined into it two sets of four timing
reference notches including a 60 degree signature
notch (Fig. 6). From the crankshaft position sensor
input the PCM determines engine speed and crank-
shaft angle (position).
The notches generate pulses from high to low in
the crankshaft position sensor output voltage. When
a metal portion of the counterweight aligns with the
crankshaft position sensor, the sensor output voltage
goes low (less than 0.5 volts). When a notch aligns
with the sensor, voltage goes high (5.0 volts). As a
group of notches pass under the sensor, the output
voltage switches from low (metal) to high (notch)
then back to low.
If available, an oscilloscope can display the square
wave patterns of each voltage pulse. From the fre-
quency of the output voltage pulses, the PCM calcu-
lates engine speed. The width of the pulses represent
the amount of time the output voltage stays high
before switching back to low. The period of time the
sensor output voltage stays high before switching
back to low is referred to as pulse-width. The faster
the engine is operating, the smaller the pulse-width
on the oscilloscope.
By counting the pulses and referencing the pulse
from the 60 degree signature notch, the PCM calcu-
lates crankshaft angle (position). In each group of
timing reference notches, the first notch represents
69 degrees before top dead center (BTDC). The sec-
ond notch represents 49 degrees BTDC. The third
notch represents 29 degrees. The last notch in eachset represents 9 degrees before top dead center
BTDC.
The timing reference notches are machined at 20É
increments. From the voltage pulse-width the PCM
tells the difference between the timing reference
notches and the 60 degree signature notch. The 60
degree signature notch produces a longer pulse-width
than the smaller timing reference notches. If the
camshaft position sensor input switches from high to
low when the 60 degree signature notch passes under
the crankshaft position sensor, the PCM knows cylin-
der number one is the next cylinder at TDC.
The crankshaft position sensor mounts to the
engine block behind the generator, just above the oil
filter (Fig. 7).
CAMSHAFT POSITION SENSOR
The PCM determines fuel injection synchronization
and cylinder identification from inputs provided by
Fig. 6 Timing Reference Notches
Fig. 7 Crankshaft Position Sensor
8D - 4 IGNITION SYSTEMPL
DESCRIPTION AND OPERATION (Continued)

SOHC
The coolant sensor threads into the end of the cyl-
inder head, next to the camshaft position sensor (Fig.
12). New sensors have sealant applied to the threads.
DOHC
The coolant sensor threads into the intake mani-
fold next to the thermostat housing (Fig. 13). New
sensors have sealant applied to the threads.
INTAKE AIR TEMPERATURE SENSOR
The intake air temperature sensor measures the
temperature of the air as it enters the engine. The
sensor supplies one of the inputs the PCM uses to
determine injector pulse-width.
The MAP/Intake Air Temperature (IAT) sensor,
located on the intake manifold, combines the MAP
and Intake Air Temperature (IAT) functions into one
sensor (Fig. 14) or (Fig. 15).
KNOCK SENSOR
The knock sensor threads into the side of the cyl-
inder block in front of the starter motor. When the
knock sensor detects a knock in one of the cylinders,
it sends an input signal to the PCM. In response, the
PCM retards ignition timing for all cylinders by a
scheduled amount.
Knock sensors contain a piezoelectric material
which constantly vibrates and sends an input voltage
(signal) to the PCM while the engine operates. As the
intensity of the crystal's vibration increase, the knock
sensor output voltage also increases.
NOTE: Over or under tightening effects knock sen-
sor performance, possibly causing improper spark
control.
MANIFOLD ABSOLUTE PRESSURE SENSOR (MAP)
The PCM supplies 5 volts to the MAP sensor. The
MAP sensor function converts intake manifold pres-
sure into voltage. The PCM monitors the MAP sensor
output voltage. As vacuum increases, MAP sensor
voltage decreases proportionately. Also, as vacuum
decreases, MAP sensor voltage increases proportion-
ately.
Key on, before the engine starts running, the PCM
determines atmospheric air pressure from the MAP
sensor voltage. While the engine operates, the PCM
determines intake manifold pressure from the MAP
sensor voltage. Based on MAP sensor voltage and
inputs from other sensors, the PCM adjusts spark
advance and the air/fuel mixture.
The MAP/IAT sensor mounts to the intake mani-
fold (Fig. 14) or (Fig. 15).
THROTTLE POSITION SENSOR (TPS)
The TPS mounts to the side of the throttle body.
The TPS connects to the throttle blade shaft. The
TPS is a variable resistor that provides the Power-
Fig. 12 Engine Coolant Temperature SensorÐSOHC
Fig. 13 Engine Coolant Temperature SensorÐDOHC
Fig. 14 MAP/IAT sensorÐSOHC
8D - 6 IGNITION SYSTEMPL
DESCRIPTION AND OPERATION (Continued)

train Control Module (PCM) with an input signal
(voltage). The signal represents throttle blade posi-
tion. As the position of the throttle blade changes,
the resistance of the TPS changes.
The PCM supplies approximately 5 volts to the
TPS. The TPS output voltage (input signal to the
powertrain control module) represents throttle blade
position. The TPS output voltage to the PCM varies
from approximately 0.38 volts to 1.2 volts at mini-
mum throttle opening (idle) to a maximum of 3.1
volts to 4.4 volts at wide open throttle.
Along with inputs from other sensors, the PCM
uses the TPS input to determine current engine oper-
ating conditions. The PCM also adjusts fuel injector
pulse width and ignition timing based on these
inputs.
IGNITION SWITCH
In the RUN position, the ignition switch connects
power from the Power Distribution Center (PDC) to a
30 amp fuse in the fuse block, back to a bus bar in
the PDC. The bus bar feeds circuits for the Power-
train Control Module (PCM), duty cycle purge sole-
noid, EGR solenoid, and ABS system. The bus bar in
the PDC feeds the coil side of the radiator fan relay,
A/C compressor clutch relay, and the fuel pump relay.
It also feeds the Airbag Control Module (ACM)
LOCK KEY CYLINDER
The lock cylinder is inserted in the end of the
housing opposite the ignition switch. The ignition key
rotates the cylinder to 5 different detents (Fig. 16):
²Accessory
²Off (lock)
²Unlock
²On/Run
²Start
IGNITION INTERLOCK
All vehicles equipped with automatic transaxles
have an interlock system. The system prevents shift-
ing the vehicle out of Park unless the ignition lock
cylinder is in the Off, Run or Start position. In addi-
tion, the operator cannot rotate the key to the lock
position unless the shifter is in the park position. On
vehicles equipped with floor shift refer to Group 21 -
Transaxle for Automatic Transmission Shifter/Igni-
tion Interlock.
DIAGNOSIS AND TESTING
TESTING FOR SPARK AT COILÐ2.0/2.4L
WARNING: THE DIRECT IGNITION SYSTEMS GEN-
ERATES APPROXIMATELY 40,000 VOLTS. PER-
SONAL INJURY COULD RESULT FROM CONTACT
WITH THIS SYSTEM.
The coil pack contains independent coils. Each coil
must be checked individually.
CAUTION: Spark plug wire damage may occur if
the spark plug is moved more than 1/4 inch away
from the engine ground.
CAUTION: Do not leave any one spark plug cable
disconnected any longer than 30 seconds or possi-
ble heat damage to catalytic converter will occur.
CAUTION: Test must be performed at idle and in
park only with the parking brake on.
NOTE: New isolated engine valve cover may not
provide adequate ground. Use engine block as
engine ground.
Fig. 15 MAP/IAT sensorÐDOHCFig. 16 Ignition Lock Cylinder Detents
PLIGNITION SYSTEM 8D - 7
DESCRIPTION AND OPERATION (Continued)

ply circuit shorts to ground, neither sensor will pro-
duce a signal (output voltage to the PCM).
When the ignition key is turned and left in the On
position, the PCM automatically energizes the Auto
Shutdown (ASD) relay. However, the controller de-en-
ergizes the relay within one second because it has
not received a camshaft position sensor signal indi-
cating engine rotation.
During cranking, the ASD relay will not energize
until the PCM receives a camshaft position sensor
signal. Secondly, the ASD relay remains energized
only if the controller senses a crankshaft position
sensor signal immediately after detecting the cam-
shaft position sensor signal.
(1) Check battery voltage. Voltage should approxi-
mately 12.66 volts or higher to perform failure to
start test.
(2) Disconnect the harness connector from the coil
pack (Fig. 20).
(3) Connect a test light to the B+ (battery voltage)
terminal of the coil electrical connector and ground.
The B+ wire for the DIS coil is the center terminal.
Do not spread the terminal with the test light
probe.
(4) Turn the ignition key to theON position.The
test light should flash On and then Off.Do not turn
the Key to off position, leave it in the On posi-
tion.
(a) If the test light flashes momentarily, the
PCM grounded the ASD relay. Proceed to step 5.
(b) If the test light did not flash, the ASD relay
did not energize. The cause is either the relay or
one of the relay circuits. Use the DRB scan tool to
test the ASD relay and circuits. Refer to the appro-
priate Powertrain Diagnostics Procedure Manual.
Refer to the wiring diagrams section for circuit
information.
(5) Crank the engine. (If the key was placed in the
off position after step 4, place the key in the On posi-tion before cranking. Wait for the test light to flash
once, then crank the engine.)
(6) If the test light momentarily flashes during
cranking, the PCM is not receiving a crankshaft posi-
tion sensor signal.
(7) If the test light did not flash during cranking,
unplug the crankshaft position sensor connector.
Turn the ignition key to the off position. Turn the
key to the On position, wait for the test light to
momentarily flash once, then crank the engine. If the
test light momentarily flashes, the crankshaft posi-
tion sensor is shorted and must be replaced. If the
light did not flash, the cause of the no-start is in
either the crankshaft position sensor/camshaft posi-
tion sensor 8 volt supply circuit, or the camshaft
position sensor output or ground circuits.
IGNITION TIMING PROCEDURE
The engines for this vehicle, use a fixed ignition
system. The PCM regulates ignition timing. Basic
ignition timing is not adjustable.
CAMSHAFT POSITION SENSOR AND CRANKSHAFT
POSITION SENSOR
The output voltage of a properly operating cam-
shaft position sensor or crankshaft position sensor
switches from high (5.0 volts) to low (0.3 volts). By
connecting an Moper Diagonostic System (MDS) and
engine analyzer to the vehicle, technicians can view
the square wave pattern.
ENGINE COOLANT TEMPERATURE SENSOR
Refer to Group 14, Fuel System for Diagnosis and
Testing.
INTAKE AIR TEMPERATURE SENSOR
Refer to Group 14, Fuel System, for Diagnosis and
Testing.
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
TEST
Refer to Group 14, Fuel System for Diagnosis and
Testing.
THROTTLE POSITION SENSOR
To perform a complete test of the this sensor and
its circuitry, refer to the DRB scan tool and appropri-
ate Powertrain Diagnostics Procedures manual. To
test the throttle position sensor only, refer to the fol-
lowing:
The Throttle Position Sensor (TPS) can be tested
with a digital voltmeter (DVM). The center terminal
of the sensor is the output terminal. One of the other
terminals is a 5 volt supply and the remaining ter-
minal is ground.
Fig. 20 Ignition Coil Engine Harness Connector
PLIGNITION SYSTEM 8D - 9
DIAGNOSIS AND TESTING (Continued)

assure gasket rails are flat. Flatten rails with a ham-
mer on a heavy steel plate if required. Gasket sur-
faces must be free of oil and dirt. Make sure old
gasket material is removed from blind attaching
holes.
FORM-IN-PLACE GASKET APPLICATION
Assembling parts using a form-in-place gasket
requires care but it's easier then using precut gas-
kets.
MopartGasket Maker material should be applied
sparingly 1 mm (0.040 inch.) diameter or less of seal-
ant to one gasket surface. Be certain the material
surrounds each mounting hole. Excess material can
easily be wiped off. Components should be torqued in
place within 15 minutes. The use of a locating dowel
is recommended during assembly to prevent smear-
ing material off the location.
The MopartSilicone Rubber Adhesive Sealant gas-
ket material or equivalent should be applied in a con-
tinuous bead approximately 3 mm (0.120 inch) in
diameter. All mounting holes must be circled. For
corner sealing, a 3.17 or 6.35 mm (1/8 or 1/4 inch.)
drop is placed in the center of the gasket contact
area. Uncured sealant may be removed with a shop
towel. Components should be torqued in place while
the sealant is still wet to the touch (within 10 min-
utes). The usage of a locating dowel is recommended
during assembly to prevent smearing material off the
location.
CRANKSHAFT SPROCKET BOLT ACCESS PLUG
An Access plug is located in the right inner fender
shield. Remove the plug and insert the proper size
socket, extension and ratchet, when crankshaft rota-
tion is necessary.
ENGINE CORE PLUGS
REMOVAL
Using a blunt tool such as a drift or a screwdriver
and a hammer, strike the bottom edge of the cup
plug (Fig. 1). With the cup plug rotated, grasp firmly
with pliers or other suitable tool and remove plug
(Fig. 1).
CAUTION: Do not drive cup plug into the casting
as restricted cooling can result and cause serious
engine problems.
INSTALLATION
Thoroughly remove all rust and clean inside of cup
plug hole in cylinder block or head. Be sure to
remove old sealer. Lightly coat inside of cup plug hole
with sealer. Make certain the new plug is cleaned of
all oil or grease. Using proper drive plug, drive plug
into hole so that the sharp edge of the plug is atleast 0.5 mm (0.020 inch.) inside the lead in chamfer
(Fig. 1).
It is in not necessary to wait for curing of the seal-
ant. The cooling system can be refilled and the vehi-
cle placed in service immediately.
ENGINE PERFORMANCE
If a loss of performance is noticed, timing belt or
chain may have skipped one or two teeth. Camshaft
and crankshaft timing should be checked. Refer to
Group 9, Engine Timing belt or chain installation.
It is important that the vehicle is operating to its
optimum performance level to maintain fuel economy
and lowest vehicle emissions. If vehicle is not operat-
ing to these standards, refer to Engine Diagnosis out-
lined is this section. The following procedures can
assist in achieving the proper engine diagnosis.
(1) Test cranking amperage draw. Refer to Group
8B, Starting.
(2) Check intake manifold for vacuum leaks.
(3) Perform cylinder compression pressure test.
Refer to Engine Diagnosis, outlined in this section.
(4) Clean or replace spark plugs as necessary and
adjust gap as specified in Group 8D, Ignition System.
Tighten to specifications.
(5) Test resistance of spark plug cables. Refer to
Group 8D, Ignition System.
(6) Test ignition coils primary and secondary resis-
tance. Replace parts as necessary. Refer to Group 8D,
Ignition System.
(7) Check fuel pump pressure at idle and different
RPM ranges. Refer to Group 14, Fuel System for
Specifications.
(8) The air filter elements should be replaced as
specified in Group 0, Lubrication and Maintenance.
(9) Inspect crankcase ventilation system as out-
lined in Group 25, Emission Control Systems.
(10) Road test vehicle as a final test.
Fig. 1 Core Hole Plug Removal
9 - 2 ENGINEPL
GENERAL INFORMATION (Continued)

ENGINE DIAGNOSISÐPERFORMANCE
CONDITION POSSIBLE CAUSE CORRECTION
ENGINE WILL NOT
START1. Weak battery. 1. Test battery. Charge or replace as necessary.
Refer to Group 8A, Battery.
2. Corroded or loose battery connections. 2. Clean and tighten battery connections. Apply a
coat of light mineral grease to terminals.
3. Faulty starter. Test starting system. Refer to Group 8B, Starting.
4. Moisture on ignition wires. 4. Remove moisture from wires.
5. Faulty ignition cables. 5. Replace any cracked or shorted cables.
6. Faulty coil or control unit. 6. Test and replace as needed. Refer to Group 8D,
Ignition System
7. Incorrect spark plug gap. 7. Set gap. Refer to Group 8D, Ignition System.
8. Contamination in fuel system. 8. Clean system and replace fuel filter.
9. Faulty fuel pump. 9. Test fuel pump and replace as needed. Refer to
Group 14, Fuel System.
ENGINE STALLS OR
IDLES ROUGH1. Idle speed too low. 1. Test minimum air flow. Refer to Group 14, Fuel
System.
2. Incorrect fuel mixture. 2. Refer to Group 14, Fuel System.
3. Intake manifold leakage. 3. Inspect intake manifold, manifold gasket, and
vacuum hoses. Refer to Group 11, Exhaust System
and Intake Manifold.
4. Incorrect ignition wiring. 4. Install correct wiring.
5. Faulty coil(s) 5. Test and replace as necessary. Refer to Group
8D, Ignition System.
ENGINE LOSS OF
POWER1. Dirty or incorrectly gapped plugs. 1. Clean plugs and set gap. Refer to Group 8D,
Ignition System.
2. Contamination in fuel system. 2. Clean system and replace fuel filter.
3. Faulty fuel pump. 3. Test and replace as necessary. Refer to Group
14, Fuel System.
4. Incorrect valve timing. 4. Correct valve timing.
5. Leaking cylinder head gasket. 5. Replace cylinder head gasket.
6. Low compression. 6. Test compression of each cylinder.
7. Burned, warped, or pitted valves. 7. Replace valves.
8. Plugged or restricted exhaust system. 8. Install new parts, as necessary.
9. Faulty ignition cables. 9. Replace any cracked or shorted cables.
10. Faulty coil(s). 10. Test and replace as necessary. Refer to Group
8D, Ignition System.
ENGINE MISSES ON
ACCELERATION1. Dirty or incorrectly gapped spark plugs. 1. Clean spark plugs and set gap. Refer to Group
8D, Ignition System.
2. Contamination in Fuel System. 2. Clean fuel system and replace fuel filter.
3. Burned, warped, or pitted valves. 3. Replace valves.
4. Faulty coil(s). 4. Test and replace as necessary. Refer to Group
8D, Ignition System.
ENGINE MISSES AT
HIGH SPEED1. Dirty or incorrect spark plug gap. 1. Clean spark plugs and set gap. Refer to Group
8D, Ignition System.
2. Faulty coil(s). 2. Test and replace as necessary. Refer to Group
8D, Ignition System.
3. Dirty fuel injector(s). Test and replace as necessary. Refer to Group 14,
Fuel System.
4. Contamination in fuel system. 4. Clean system and replace fuel filter.
9 - 10 ENGINEPL
DIAGNOSIS AND TESTING (Continued)

2.0L SOHC ENGINE
INDEX
page page
DESCRIPTION AND OPERATION
ENGINE COMPONENTS.................. 14
ENGINE IDENTIFICATION................. 12
ENGINE LUBRICATION SYSTEM............ 13
GENERAL SPECIFICATION................ 12
DIAGNOSIS AND TESTING
CHECKING ENGINE OIL PRESSURE......... 14
SERVICE PROCEDURES
CRANKSHAFT END PLAY................. 16
CYLINDER BORE AND PISTON SIZING....... 14
FITTING CONNECTING RODS.............. 16
FITTING CRANKSHAFT BEARINGS.......... 16
FITTING PISTON RINGS.................. 16
REMOVAL AND INSTALLATION
CAMSHAFT OIL SEAL.................... 28
CAMSHAFT............................ 22
CRANKSHAFT DAMPER.................. 46
CRANKSHAFT OIL SEALÐFRONT........... 37
CRANKSHAFT OIL SEALÐREAR............ 38
CRANKSHAFT.......................... 39
CYLINDER HEAD COVER................. 21
CYLINDER HEAD........................ 25
ENGINE ASSEMBLY...................... 19
ENGINE MOUNTÐFRONT................. 18
ENGINE MOUNTÐLEFT................... 18
ENGINE MOUNTÐRIGHT................. 18
OIL FILTER ADAPTER.................... 42OILFILTER ............................ 42
OILPAN ............................... 36
OIL PUMP............................. 42
PISTON AND CONNECTING ROD........... 44
POWER HOP DAMPER................... 18
ROCKER ARM/HYDRAULIC LASH ADJUSTER . . 23
SPARK PLUG TUBE...................... 21
STRUCTURAL COLLARÐ2.0L.............. 19
TIMING BELT COVER.................... 27
TIMING BELT TENSIONERÐMECHANICAL.... 36
TIMING BELTÐWITH HYDRAULIC TENSIONER . 28
TIMING BELTÐWITH MECHANICAL
TENSIONER.......................... 33
VALVE SEALS AND SPRINGS IN VEHICLE.... 24
DISASSEMBLY AND ASSEMBLY
OIL PUMP............................. 47
VALVE SERVICE WITH THE CYLINDER HEAD
REMOVED........................... 47
CLEANING AND INSPECTION
CYLINDER BLOCK AND BORE............. 51
CYLINDER HEAD AND CAMSHAFT JOURNALS . 50
OIL PUMP............................. 50
SPECIFICATIONS
2.0L SOHC............................. 52
TORQUE CHART 2.0L SOHC............... 54
SPECIAL TOOLS
2.0L SOHC............................. 55
DESCRIPTION AND OPERATION
ENGINE IDENTIFICATION
The engine identification number is located on the
left rear of the cylinder block behind starter (Fig. 1).
GENERAL SPECIFICATION
Type ..............In-Line OHV, DOHC & SOHC
Bore......................87.5mm (3.445 Inch)
Stroke.....................83.0mm (3.268 inch)
Compression Ratio.....DOHC - 9.6:1 SOHC - 9.8:1
Displacement..........2.0 Liters (122 Cubic Inch)
Firing Order.........................1,3,4,2
Compression Pressure............1172-1551 kPa
(170 - 225 psi)
Maximum Variation Between Cylinders.......25%
Lubrication. . . .Pressure Feed - Full Flow Filtration
(Crankshaft Driven Pump)
Engine Oil Capacity............Refer to Group 0,
Lubrication and Maintenance
Fig. 1 Engine Identification SOHC
9 - 12 2.0L SOHC ENGINEPL