engine coolant CHRYSLER VOYAGER 1996 Owner's Guide

SERVICE PROCEDURES
ADDING ADDITIONAL COOLANT
2.5L VM DIESEL
Do not remove coolant bottle pressure cap when
the engine is hot. Remove pressure cap and fill cool-
ant bottle between Min and Max lines inside filler
neck. Use only 50/50 mix of ethylene glycol type anti-
freeze and water (Fig. 13). Squeezing radiator hoses
may help purge air from the cooling system.
DRAINING COOLING SYSTEM
2.0L GASOLINE
To drain cooling system move temperature selector
for heater to full heat with engine running.Without
removing radiator pressure cap and with sys-
tem not under pressure,Shut engine off and open
draincock. The coolant reserve tank should empty
first, then remove radiator pressure cap and let the
radiator drain (if not, see Testing Cooling System for
leaks).
2.5L VM DIESEL
The cooling system does not have a radiator
mounted pressure cap. Instead the pressure cap is
mounted on the coolant pressure bottle (Fig. 14).
(1) Shut off engine.
(2) Remove radiator pressure cap.
(3) Open draincock and allow coolant to drain.
REFILLING COOLING SYSTEM
2.0L GASOLINE
Refer to the gasoline engine cooling system infor-
mation in this manual. Cooling system capacity is 6.0
liters (6.34 qts.) which includes the heater and cool-
ant recovery tank.
2.5L VM DIESEL
First clean system to remove old glycol, see Cooling
System Cleaning.
(1) Disconnect upper radiator hose at thermostat
housing.
(2) Remove pressure cap from coolant expansion
tank.
(3) Fill cooling system through upper radiator hose
until coolant starts to leak out at the thermostat
housing. Reconnect hose and re-install clamp.
(4) Fill expansion tank to top of bottle. Run engine
at idle without pressure cap installed for 5 minutes.
Squeeze upper radiator hose several times.
(5) Shut off engine. Top off coolant and install
pressure cap.
(6) Inspect system for leaks.
REMOVAL AND INSTALLATION
WATER PUMP Ð 2.0L GASOLINE
REMOVAL
(1) Remove accessory drive belts and power steer-
ing pump.
(2) Drain cooling system.
Fig. 13 Coolant Pressure BottleÐ2.5L VM Diesel
Fig. 14 Pressure Cap and BottleÐVM Diesel
NS/GSCOOLING SYSTEM 7 - 7

(3) Remove power steering pump bracket bolts and
set pump and bracket assembly aside. Power steering
lines do not need to be disconnected.
(4) Remove timing belt.
(5) Remove inner timing belt cover.
(6) Remove water pump attaching screws to engine
(Fig. 15).
INSTALLATION
(1) Install new O-ring gasket in water pump body
O-ring groove (Fig. 16). Use small dabs of Mopar Sil-
icone Rubber Adhesive Sealant around the water
pump body to secure O-ring in place during installa-
tion.
CAUTION: Make sure O-ring gasket is properly
seated in water pump groove before tightening
screws. An improperly located O-ring may cause
damage to the O-ring and cause a coolant leak.
(2) Assemble pump body to block and tighten
screws to 12 N´m (105 in. lbs.). Pressurize cooling
system to 15 psi with pressure tester and check
water pump shaft seal and O-ring for leaks.
(3) Rotate pump by hand to check for freedom of
movement.
(4) Install inner timing belt cover.
(5) Install timing belt.
(6) Fill cooling system. SeeFilling Cooling Sys-
tem.
(7) Install power steering pump and accessory
drive belts.
WATER PUMP Ð 2.5L VM DIESEL
REMOVAL
(1) Drain cooling system. Refer to Draining Cool-
ing System in this Group.
(2) Remove the right inner splash shield (Fig. 17).
(3) Loosen the water pump pulley attaching bolts
(Fig. 18) before the accessory drive belt is removed.
(4) Loosen water pump accessory drive belts (Fig.
19). Remove water pump pulley.(5) Remove water pump attaching bolts and
remove pump.
INSTALLATION
(1) Install a new water pump to housing O-ring
gasket. Install pump and tighten the attaching bolts
to 22.6 N´m (205 in. lbs.)
Fig. 15 Water Pump Ð 2.0L Gasoline
Fig. 16 Water Pump Body Ð 2.0L Gasoline
Fig. 17 Right Side Splash Shield
Fig. 18 Water Pump and Pulley Ð 2.5 L VM Diesel
7 - 8 COOLING SYSTEMNS/GS
REMOVAL AND INSTALLATION (Continued)

(2) Install water pump pulley.
(3) Install drive belt, Refer to Accessory Drive
Belts, this Group. Tighten water pump pulley attach-
ing bolts to 27.5 N´m (240 in. lbs.)
(4) Install right inner splash shield.
(5) Refill cooling system. Refer to Refilling Cooling
System in this Group.
ENGINE THERMOSTATÐ 2.0L GASOLINE
REMOVAL
(1) Drain cooling system to the thermostat level or
below.
(2) Remove coolant recovery system (CRS) hose
and thermostat/engine outlet connector bolts.
(3) Remove thermostat and seal, and clean sealing
surfaces.
INSTALLATION
(1) Place the new thermostat assembly into the
thermostat housing/outlet connector. Align air bleed
vent with notch in cylinder head.
(2) Install thermostat housing/outlet connector
onto cylinder head and tighten bolts to 12.5 N´m (110
in. lbs.). Connect the upper radiator hose.
(3) Refill cooling system (seeRefilling System).
THERMOSTAT Ð 2.5L VM DIESEL
REMOVAL
(1) Drain cooling system down below the thermo-
stat level. Refer to Draining Cooling System in this
section.(2) Remove radiator hose at thermostat cover.
(3) Remove thermostat cover bolts (Fig. 20).
(4) Remove Thermostat.
INSTALLATION
(1) Remove old gasket material from thermostat
housing and cover.
(2) Install new thermostat gasket.
(3) Install thermostat and tighten cover bolts to
10.8 N´m (96 in. lbs.).
(4) Install radiator hose.
(5) Refill cooling system. Refer to Refilling Cooling
System in this section.
RADIATOR Ð 2.5L VM DIESEL
REMOVAL
(1) Disconnect battery.
(2) Remove power steering reservoir attaching
bolts, and reposition reservoir.
(3) Remove radiator closure panel crossmember
(Fig. 21).
(4) Remove air cleaner housing and intake hose.
(5) Unplug fan module 4 pin wiring connector.
(6) Drain cooling system. Refer to Draining cooling
system in this section for procedure.
(7) Remove upper and lower Radiator Hoses.
(8) Remove radiator attaching bolts.
(9) Loosen A/C receiver/dryer lower bolt.
(10) Remove Radiator.
(11) Remove fan module from radiator.
Fig. 19 Water Pump Drive BeltÐ 2.5 L VM Diesel
Fig. 20 Thermostat and Housing Ð 2.5L VM Diesel
NS/GSCOOLING SYSTEM 7 - 9
REMOVAL AND INSTALLATION (Continued)

(2) Coolant leaks; if the seal is leaking, this will be
evident by traces of thick deposits of greenish-brown
dried glycol running down the pump body and com-
ponents below. A thin black stain below pump weep
hole is considered normal operation.
(3) Impeller rubs inside of the cylinder block 2.0L
engine. Impeller rubs inside of the water pump hous-
ing 2.5L VM diesel engine.
(4) Excessively loose or rough turning bearing.
NOTE: It is normal for the water pump to weep a
small amount of coolant from the weep hole (black
stain on water pump body). Do not replace the
water pump if this condition exists. Replace the
water pump if a heavy deposit or a steady flow of
green/brown engine coolant is evident on water
pump body from the weep hole (shaft seal failure).
Be sure to perform a thorough analysis before
replacing water pump.
ADJUSTMENTS
BELT TENSION GAUGE METHOD
Use belt tensioning Special Tool Kit C-4162 for:
CAUTION: The Burroughs gauge for the Poly-V
belt is not to be used on the V-belt. These gauges
are not interchangeable.
²For conventional V-belts affix the Burroughs
gauge (Special Tool C-4162) to the belt. Adjust the
belt tension for New or Used belt as prescribed in the
Belt Tension Chart. For a Poly-V belt affix the Poly-V
Burroughs gauge to the belt and then apply specified
tension to the belt as prescribed in the Belt Tension
Chart
Adjust the belt tension for aNeworUsedbelt as
prescribed in the Belt Tension Chart.
BELT TENSION CHART
Fig. 24 Generator/Power Steering Removal ± 2.5L
VM Diesel
ACCESSORY DRIVE
BELTGAUGE
2.0L GASOLINE ENGINE
GENERATOR AND AIR
CONDITIONINGNEW 667644 N (150
610 LBS).
USED 556 N (125 LBS.)
POWER STEERING NEW 578644 N (130
610 LBS).
USED 489 N (110 LBS).
2.5L VM DIESEL
WATER PUMP NEW N/A LBS.
USED N/A LBS.
GENERATOR /AIR
CONDITIONING/
POWER STEERINGNEW 667644 N (150
610 LBS).
USED 556 N (125 LBS).
NS/GSCOOLING SYSTEM 7 - 11
CLEANING AND INSPECTION (Continued)

IGNITION SYSTEM
CONTENTS
page page
GENERAL INFORMATION................... 1
2.4L ENGINE............................ 16
3.0L ENGINE............................ 233.3/3.8L ENGINE........................ 28
IGNITION SWITCH AND LOCK CYLINDER..... 35
GENERAL INFORMATION
INDEX
page page
GENERAL INFORMATION
AUTOMATIC SHUTDOWN (ASD) RELAY....... 4
CAMSHAFT POSITION SENSOR............. 5
CRANKSHAFT POSITION SENSOR........... 5
ENGINE COOLANT TEMPERATURE (ECT)
SENSOR.............................. 6
IGNITION COIL.......................... 4
IGNITION SYSTEM....................... 2
INTRODUCTION......................... 1
KNOCK SENSOR......................... 7
LOCK KEY CYLINDER..................... 7
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR.............................. 6
POWERTRAIN CONTROL MODULE........... 1
SPARK PLUG CABLE...................... 3
SPARK PLUGSÐ2.4/3.0L................... 2
SPARK PLUGSÐ3.3/3.8L................... 2
THROTTLE POSITION SENSOR (TPS)........ 7DIAGNOSIS AND TESTING
CAMSHAFT POSITION SENSOR AND
CRANKSHAFT POSITION SENSOR......... 11
CHECK COIL TESTÐ2.4L.................. 9
CHECK COIL TESTÐ3.3/3.8L................ 9
ENGINE COOLANT TEMPERATURE SENSOR . . 11
FAILURE TO START TEST................. 10
IGNITION TIMING PROCEDURE............ 11
INTAKE AIR TEMPERATURE SENSOR........ 11
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR TEST........................ 11
SPARK PLUG CONDITION................. 11
TESTING FOR SPARK AT COILÐ2.4/3.3/3.8L
ENGINES............................. 8
TESTING FOR SPARK AT COILÐ3.0L......... 8
THROTTLE POSITION SENSOR............ 13
SERVICE PROCEDURES
IGNITION TIMING PROCEDURE............ 15
POWERTRAIN CONTROL MODULE.......... 13
SPARK PLUG GAP ADJUSTMENT........... 13
GENERAL INFORMATION
INTRODUCTION
This group describes the ignition systems for the
2.4, 3.0, and 3.3/3.8L engines.
On Board Diagnostics is described in Group 25 -
Emission Control Systems.
Group 0 - Lubrication and Maintenance, contains
general maintenance information for ignition related
items. The Owner's Manual also contains mainte-
nance information.
POWERTRAIN CONTROL MODULE
The ignition system is regulated by the Powertrain
Control Module (PCM) (Fig. 1). The PCM supplies
battery voltage to the ignition coil through the Auto
Shutdown (ASD) Relay. The PCM also controls
ground circuit for the ignition coil. By switching the
ground path for the coil on and off, the PCM adjusts
ignition timing to meet changing engine operating
conditions.
During the crank-start period the PCM advances
ignition timing a set amount. During engine opera-
tion, the amount of spark advance provided by the
PCM is determined by the following input factors:
NSIGNITION SYSTEM 8D - 1

²available manifold vacuum
²barometric pressure
²engine coolant temperature
²engine RPM
²intake air temperature (2.4L only)
²throttle position
The PCM also regulates the fuel injection system.
Refer to the Fuel Injection sections of Group 14.
IGNITION SYSTEM
NOTE: The 2.4, 3.0 and 3.3/3.8L engines use a fixed
ignition timing system. Basic ignition timing is not
adjustable. All spark advance is determined by the
Powertrain Control Module (PCM).
The distributorless ignition system used on 2.4 and
3.3/3.8L engines is refered to as the Direct Ignition
System (DIS). The system's three main components
are the coil pack, crankshaft position sensor, and
camshaft position sensor. The crankshaft position
sensor and camshaft position sensor are hall effect
devices.
The 3.0L engine uses a distributor, crankshaft sen-
sor and ignition coil. The system's main components
are the distributor, distributor pickup, camshaft sig-
nal, crankshaft signal and ignition coil.
SPARK PLUGSÐ2.4/3.0L
All engines use resistor spark plugs. They have
resistance values ranging from 6,000 to 20,000 ohms
when checked with at least a 1000 volt spark plug
tester.Do not use an ohm meter to check the resis-
tance of the spark plugs. This will give an inac-
curate reading.
Remove the spark plugs and examine them for
burned electrodes and fouled, cracked or broken por-
celain insulators. Keep plugs arranged in the order
in which they were removed from the engine. An iso-
lated plug displaying an abnormal condition indicates
that a problem exists in the corresponding cylinder.
Replace spark plugs at the intervals recommended in
Group O - Lubrication and Maintenance.
Spark plugs that have low mileage may be cleaned
and reused if not otherwise defective, carbon or oil
fouled. Refer to the Spark Plug Condition section of
this group. After cleaning, file the center electrode
flat with a small flat point file or jewelers file. Adjust
the gap between the electrodes (Fig. 2) to the dimen-
sions specified in the chart at the end of this section.
Special care should be used when installing spark
plugs in the 2.4L cylinder head spark plug wells. Be
sure the plugs do not drop into the wells, damage to
the electrodes can occur.
Always tighten spark plugs to the specified torque.
Over tightening can cause distortion resulting in a
change in the spark plug gap. Overtightening can
also damage the cylinder head. Tighten spark plugs
to 28 N´m (20 ft. lbs.) torque.SPARK PLUGSÐ3.3/3.8L
The 3.3/3.8L engines utilize platinum spark plugs.
Refer to the maintenance schedule in Group 0 of this
service manual.
Fig. 1 Powertrain Control Module
Fig. 2 Setting Spark Plug Electrode Gap
8D - 2 IGNITION SYSTEMNS
GENERAL INFORMATION (Continued)

cylinder 4 crankshaft timing marks follow. One cam-
shaft pulse after the 3 pulses indicates cylinder 5.
The 2 camshaft pulses after cylinder 5 signals cylin-
der 6 (Fig. 10). The PCM can synchronize on cylin-
ders1or4.
When metal aligns with the sensor, voltage goes
low (less than 0.3 volts). When a notch aligns with
the sensor, voltage switches high (5.0 volts). As a
group of notches pass under the sensor, the voltage
switches from low (metal) to high (notch) then back
to low. The number of notches determine the amount
of pulses. If available, an oscilloscope can display the
square wave patterns of each timing event.
Top Dead Center (TDC) does not occur when
notches on the camshaft sprocket pass below the cyl-
inder. TDC occurs after the camshaft pulse (or
pulses) and after the 4 crankshaft pulses associated
with the particular cylinder. The arrows and cylinder
call outs on Figure 4 represent which cylinder the
flat spot and notches identify, they do not indicate
TDC position.
The camshaft position sensor is mounted in the
front of the timing case cover (Fig. 11).
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
The MAP sensor reacts to absolute pressure in the
intake manifold and provides an input voltage to the
Powertrain Control Module (PCM). As engine load
changes, manifold pressure varies. The changes in
engine load cause the MAP sensors resistance to
change. The change in MAP sensor resistance results
in a different input voltage to the PCM.
The input voltage level supplies the PCM with
information relating to ambient barometric pressure
during engine start-up (cranking) and engine load
while its operating. Based on MAP sensor voltage
and inputs from other sensors, the PCM adjusts
spark advance and the air-fuel mixture.
ENGINE COOLANT TEMPERATURE (ECT) SENSOR
The ECT sensor is located next to the thermostat
housing (Fig. 12). The sensor provides an input volt-
age to the Powertrain Control Module (PCM). Thesensor is a variable resistance (thermistor) with a
range of -40ÉF to 265ÉF. As coolant temperature var-
ies, the sensors resistance changes, resulting in a dif-
ferent input voltage to the PCM.
The PCM contains different spark advance sched-
ules for cold and warm engine operation. The sched-
ules reduce engine emission and improve driveability.
When the engine is cold, the PCM will demand
slightly richer air-fuel mixtures and higher idle
speeds until normal operating temperatures are
reached.
The ECT sensor input is also used for cooling fan
control.
Fig. 9 Camshaft Position Sensor
Fig. 10 Camshaft Sprocket
Fig. 11 Camshaft Position Sensor Location
8D - 6 IGNITION SYSTEMNS
GENERAL INFORMATION (Continued)

THROTTLE POSITION SENSOR (TPS)
The TPS mounts to the side of the throttle body
(Fig. 13).
The TPS connects to the throttle blade shaft. The
TPS is a variable resistor that provides the Power-
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 0.40 volt at minimum throttle
opening (idle) to a maximum of 3.80 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.
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. 14):
²Accessory
²Off (lock)
²Unlock
²On/Run
²Start
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.
Fig. 12 Engine Coolant Temperature SensorÐ3.3/
3.8LFig. 13 Throttle Position Sensor and Idle Air Control
Motor
Fig. 14 Ignition Lock Cylinder Detents
NSIGNITION SYSTEM 8D - 7
GENERAL INFORMATION (Continued)

either the crankshaft position sensor/camshaft posi-
tion sensor 8 volt supply circuit, or the camshaft
position sensor output or ground circuits. Use the
DRB scan tool to test the camshaft position sensor
and the sensor circuits. Refer to the appropriate Pow-
ertrain Diagnostics Procedure Manual. Refer to the
wiring diagrams section for circuit information.
IGNITION TIMING PROCEDURE
The engines for this vehicle, use a fixed ignition
system. The PCM regulates ignition timing. Basic
ignition timing is not adjustable.
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
TEST
Refer to Group 14, Fuel System for Diagnosis and
Testing.
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.
SPARK PLUG CONDITION
NORMAL OPERATING CONDITIONS
The few deposits present will be probably light tan
or slightly gray in color with most grades of commer-
cial gasoline (Fig. 23). There will not be evidence of
electrode burning. Gap growth will not average more
than approximately 0.025 mm (.001 in) per 1600 km
(1000 miles) of operation for non platinum spark
plugs. Non-platnium spark plugs that have normal
wear can usually be cleaned, have the electrodes filed
and regapped, and then reinstalled.
CAUTION: Never attempt to file the electrodes or
use a wire brush for cleaning platinum spark plugs.
This would damage the platinum pads which would
shorten spark plug life.
Some fuel refiners in several areas of the United
States have introduced a manganese additive (MMT)
for unleaded fuel. During combustion, fuel with MMT
may coat the entire tip of the spark plug with a rustcolored deposit. The rust color deposits can be misdi-
agnosed as being caused by coolant in the combustion
chamber. Spark plug performance is not affected by
MMT deposits.
COLD FOULING (CARBON FOULING)
Cold fouling is sometimes referred to as carbon
fouling because the deposits that cause cold fouling
are basically carbon (Fig. 23). A dry, black deposit on
one or two plugs in a set may be caused by sticking
valves or misfire conditions. Cold (carbon) fouling of
the entire set may be caused by a clogged air cleaner.
Cold fouling is normal after short operating peri-
ods. The spark plugs do not reach a high enough
operating temperature during short operating peri-
ods.Replace carbon fouled plugs with new
spark plugs.
FUEL FOULING
A spark plug that is coated with excessive wet fuel
is called fuel fouled. This condition is normally
observed during hard start periods.Clean fuel
fouled spark plugs with compressed air and
reinstall them in the engine.
OIL FOULING
A spark plug that is coated with excessive wet oil
is oil fouled. In older engines, wet fouling can be
caused by worn rings or excessive cylinder wear.
Break-in fouling of new engines may occur before
normal oil control is achieved.Replace oil fouled
spark plugs with new ones.
OIL OR ASH ENCRUSTED
If one or more plugs are oil or ash encrusted, eval-
uate the engine for the cause of oil entering the com-
bustion chambers (Fig. 24). Sometimes fuel additives
can cause ash encrustation on an entire set of spark
Fig. 23 Normal Operation and Cold (Carbon) Fouling
NSIGNITION SYSTEM 8D - 11
DIAGNOSIS AND TESTING (Continued)

2.4L ENGINE
INDEX
page page
DESCRIPTION AND OPERATION
CAMSHAFT POSITION SENSOR............ 17
CRANKSHAFT POSITION SENSOR.......... 16
FIRING ORDERÐ2.4L.................... 16
INTAKE AIR TEMPERATURE SENSORÐ2.4L . . . 17
REMOVAL AND INSTALLATION
CAMSHAFT POSITION SENSOR............ 19
CRANKSHAFT POSITION SENSOR.......... 19
ENGINE COOLANT TEMPERATURE SENSORÐ
2.4L................................. 20
IGNITION COILÐ2.4L..................... 18
INTAKE AIR TEMPERATURE SENSORÐ2.4L . . . 21KNOCK SENSORÐ2.4L................... 21
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSORÐ2.4/3.3/3.8L.................. 20
SPARK PLUG CABLE SERVICEÐ2.4L........ 18
SPARK PLUG SERVICE................... 18
THROTTLE POSITION SENSOR............ 20
SPECIFICATIONS
IGNITION COIL......................... 22
SPARK PLUG CABLE RESISTANCEÐ2.4L..... 22
SPARK PLUG........................... 22
TORQUE.............................. 22
DESCRIPTION AND OPERATION
FIRING ORDERÐ2.4L
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 and a 60 degree signature notch
(Fig. 1). From the crankshaft position sensor input
the PCM determines engine speed and crankshaft
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 0.3 volts). When a notch aligns
with the sensor, voltage switches 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 width
of the output voltage pulses, the PCM calculates
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
FIRING ORDERÐ2.4L
Fig. 1 Timing Reference Notches
8D - 16 IGNITION SYSTEMNS