service indicator CHEVROLET DYNASTY 1993 Owner's Manual

The MOPAR Silicone Rubber Adhesive Sealant
gasket material or equivalent should be applied in a
continuous bead approximately 3mm (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
towels. 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 of material off
location.
CRANKSHAFT SPROCKET BOLT ACCESS PLUG
An Access plug is located in the right inner fender
shield. Remove the plug and insert proper size
socket, extension and rachet, when crankshaft rota-
tion is necessary.
ENGINE PERFORMANCE
If a loss of performance is noticed, ignition timing
should be checked. If ignition timing is retarded by
9, 18 or 27É indicating 1, 2 or 3 (timing belt or chain)
teeth may have skipped, then, camshaft and acces-
sory shaft timing with the crankshaft should be
checked. Refer to Engine Timing Sprockets and Oil
Seals of the Engine Section. To provide best vehicle performance and lowest ve-
hicle emissions, it is most important that the tune-up
be done accurately. Use the specifications listed on
the Vehicle Emission Control Information label
found in the engine compartment. (1) Test cranking amperage draw. See Starting
Motor Cranking Amperage Draw Electrical Section
of this manual. (2) Tighten the intake manifold bolts to specifica-
tions. (3) Perform cylinder compression test.(a) Check engine oil level and add oil if neces-
sary. (b) Drive the vehicle until engine reaches normal
operating temperature. (c) Select a route free from traffic and other
forms of congestion, observe all traffic laws, and ac-
celerate through the gears several times briskly.
CAUTION: Do not overspeed the engine. The higher
engine speed may help clean out valve seat deposits
which can prevent accurate compression readings.
(d) Remove all spark plugs from engine. As
spark plugs are being removed, check electrodes for
abnormal firing indicators fouled, hot, oily, etc.
Record cylinder number of spark plug for future
reference. (e) Disconnect coil wire from distributor and se-
cure to good ground to prevent a spark from start- ing a fire (Conventional Ignition System). For Direct
Ignition System DIS disconnect the coil connector. (f) Be sure throttle blade is fully open during the
compression check. (g) Insert compression gage adaptor into the #1
spark plug hole in cylinder head. Crank engine until
maximum pressure is reached on gage. Record this
pressure as #1 cylinder pressure. (h) Repeat Step G for all remaining cylinders.
(i) Compression should not be less than (689kPa)
100 psi and not vary more than 25 percent from
cylinder to cylinder. (j) If one or more cylinders have abnormally low
compression pressures, repeat steps 3b through 3h. (k) If the same cylinder or cylinders repeat an
abnormally low reading on the second compression
test, it could indicate the existence of a problem in
the cylinder in question.
The recommended compression pressures are
to be used only as a guide to diagnosing engine
problems. An engine should not be disassembled
to determine the cause of low compression un-
less some malfunction is present. (4) Clean or replace spark plugs as necessary and
adjust gap as specified in Electrical Group 8. Tighten to
specifications. (5) Test resistance of spark plug cables. Refer to
Ignition System Secondary Circuit Inspection Electri-
cal Section Group 8. (6) Inspect the primary wire. Test coil output volt-
age, primary and secondary resistance. Replace parts
as necessary. Refer to Ignition System and make nec-
essary adjustment. (7) Ignition timing should be set to specifications.
(See Specification Label in engine compartment). (8) Test fuel pump for pressure and vacuum. Refer to
Fuel System Group 14, Specifications. (9) The air filter elements should be replaced as
specified in Lubrication and Maintenance, Group 0. (10) Inspect crankcase ventilation system as out
lined in Lubrication and Maintenance, Group 0. For
emission controls see Emission Controls Group 25 for
service procedures. (11) Inspect and adjust accessory belt drives refer-
ring to Accessory Belt Drive in Cooling System, Group
7 for proper adjustments. (12) Road test vehicle as a final test.
HONING CYLINDER BORES
Before honing, stuff plenty of clean shop towels
under the bores, over the crankshaft to keep abrasive
materials from entering crankcase area. (1) Used carefully, the cylinder bore resizing hone
C-823 equipped with 220 grit stones, is the best tool for
this job. In addition to deglazing, it will reduce taper
and out-of-round as well as removing light
9 - 2 ENGINE Ä

Camshaft bearing journals and lobe wear. Lobe
wear should not exceed .25mm (.010 inch). To mea-
sure cam lobe wear (Fig. 8), measure lobe diameter
in two places at the largest diameter (over the nose).
Take first reading with micrometer in unworn area
at the edge of the lobe. Take second reading in the
worn area where rocker arm contacts the lobe. Sub-
tract second reading from the first. The difference is
the cam lobe wear.
CAMSHAFT END PLAY
(1) Oil camshaft journals and install camshaft
without cam followers. Tighten screws to specified
torque. (2) Using a suitable tool, move camshaft as far
rearward as it will go. (3) Zero dial indicator (Fig. 9).
(4) Move camshaft as far forward as it will go.
(5) End play travel: 0.13 - 0.33mm (0.005 - 0.013
inch.). (6) Remove bearing caps and camshaft.
INSTALLATION
(1) Install cam followers in correct order as re-
moved. (2) Align camshaft bearing caps in proper sequence
with Cap No. 1 at timing belt end and Cap No. 5 at
transmission end. Arrows on Caps No. 1, 2, 3, 4
must point toward timing belt to prevent cap break-
age (Fig. 11). (3) Apply Mopar Gasket Maker to No.1 and No.5
bearing cap (Fig. 10). (4) Caps must be installed before camshaft seals
are installed.
LASH ADJUSTER (TAPPET) NOISE
A tappet-like noise may be produced from several
items. Refer to Lash Adjuster and Tappet Noise - Di-
agnosis in Standard Service Procedures, this Group.
VALVE COMPONENTS REPLACEÐCYLINDER HEAD NOT REMOVED
ROCKER ARM AND HYDRAULIC LASH ADJUSTER
REMOVAL
(1) Remove valve cover.
(2) For each rocker arm, rotate cam until base cir-
cle is in contact with rocker arm. Depress valve
spring using Special Tool C-4682 (Fig. 12) and slide
rocker arm out. Keep rocker arms in order for reas-
sembly. (3) Remove hydraulic lash adjuster.
INSTALLATION
(1) Install hydraulic lash adjusters making sure
that adjusters are at least partially full of oil. This is
indicated by little or no plunger travel when the lash
adjuster is depressed. (2) Rotate cam until base circle is in contact posi-
tion with rocker arm. Depress valve spring with Spe-
cial Tool C-4682 (Fig. 12) and slide rocker arm in
place. Keep rockers in order. It is possible for the
Fig. 9 Camshaft End Play
Fig. 10 Cam Tower Cap Sealing
Fig. 11 Camshaft Bearing Caps Installation
Ä 2.2/2.5L ENGINE 9 - 25

springs using Tool C-3422-B. (2) Remove valve retaining locks, valve spring re-
tainers, valve stem seals and valve springs. (3) Before removing valves, remove any burrs
from valve stem lock grooves to prevent damage
to the valve guides. Identify valves to insure instal-
lation in original location.
VALVE INSPECTION (1) Clean valves thoroughly and discard burned,
warped and cracked valves. (2) Measure valve stems for wear.
(3) If valve stems are worn more than 0.05 mm (.002
inch.) replace valve.
VALVE GUIDES
(1) Remove carbon and varnish deposits from inside
of valve guides with a reliable guide cleaner. (2) Checking Valve Guide Wear:
² Insert valve with valve head positioned 10 mm (.400
inch) above cylinder head gasket surface.
²
Move valve to and from the indicator (Fig. 17). The
total dial indicator reading should not exceed the amount
specified in (Fig. 18). Readings should be taken for length-
wise and crosswise (with respect to cylinder head) move-
ment for each valve. Ream the guides for valves with
oversize stems if dial indicator reading is excessive or if
the stems are scuffed or scored.
(3) Service valves with oversize stems and oversize
seals are available in 0.15mm, (.005 inch) 0.40mm,
(.015 inch) and 0.80mm(.031 inch) oversize. Oversize seals must be used with oversize
valves. Reamers sizes to accommodate the oversize valve
stem are shown in (Fig. 18)
(4) Slowly turn reamer by hand and clean guide thor-
oughly before installing new valve. Do not attempt to
ream the valve guides from standard directly to
0.80mm (.030 inch). Use step procedure of 0.15mm
(.005 inch), 0.40mm (.015 inch) and 0.80mm (.030 inch) so the valve guides may be reamed true in
relation to the valve seat. After reaming guides, the
seat runout should be measured and resurfaced if
necessary. Refer to Refacing Valves and Valve Seats.
Replace cylinder head if guide does not clean
up with 0.80 mm (.030 inch) oversize reamer, or if
guide is loose in cylinder head.
TESTING VALVE SPRINGS
(1) Whenever valves have been removed for inspection,
reconditioning or replacement, valve springs should be
tested. As an example, the compression length of the
spring to be tested is 33.34mm (1-5/16 inches). Turn table
of Tool C-647 until surface is in line with the 33.34mm
(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 compressing lever to set tone device (Fig. 20). 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. Fractional mea-
surements are indicated on the table for finer adjust-
ments. Refer to specifications to obtain specified height
and allowable tensions. Discard the springs that do not
meet specifications.
Fig. 18 Checking Wear on Valve GuideÐTypical
Fig. 19 Valve Guide Specification
Fig. 20 Testing Valve Spring with Tool C-647
9 - 28 2.2/2.5L ENGINE Ä

CAMSHAFT AND CRANKSHAFT TIMING
PROCEDURE
INSTALLATION
(1) Remove air cleaner fresh air duct.
(2) Remove ignition cable cover (Fig. 7).
(3) Remove valve covers and loosen rocker arm as-
semblies about 3 turns as shown in (Fig. 8).
CAUTION: Check lash adjuster for loose or missing
retainers before continuing service procedure.
(4) Align and pin both intake and exhaust cam
sprockets with 3/32 drills or pin punches (Fig. 9). Ac-
cessory Shaft does not need to be timed. (5) Remove spark plugs.
(6) Install a dial indicator in Number 1 spark plug
hole (Fig. 10). (7) Rotate crankshaft till number 1 piston is at
Top Dead Center. Mark the engine block for TDC
reference. (8) Install timing belt and idler pulley in sequence
shown in (Fig. 11). (9) Remove dial indicator from cylinder head (Fig.
10). Remove drills or pins from camshaft sprockets
(Fig. 11). (10) Adjust tension to 445 N (110 lbs.)
New beltor
311 N (70 lbs.) Used belt. Install belt tension gauge on
timing belt (Fig. 12) adjust tensioner until specified
tension is achieved.
CAUTION: Belt tension gauge must be installed be-
tween the belt teeth to get a accurate reading .
(11) Rotate crankshaft clockwise 2 full revolutions
and check alignment of camshaft and crankshaft tim-
ing marks. Do not reverse rotate crankshaft or
attempt to rotate engine using cam or accessory
shaft attaching screw.
CAUTION: Do not allow oil or solvents to contact the
timing belt as they can deteriorate the rubber and
cause tooth skipping.
Fig. 7 Ignition Cable Cover
Fig. 8 Rocker Arm Shaft Assemblies
Fig. 9 Camshafts Pinned Into Position
Fig. 10 Dial Indicator Located in Number 1 Cylinder
9 - 34 2.2/2.5L ENGINE Ä

(2) Install thrust plates and tighten retaining nuts
to6N Im (55 in. lbs.).
(3) Install new camshaft oil seals flush with cylin-
der head surface. Using seal installing special tool C-4680.
CAMSHAFT END PLAY
(1) Using a suitable tool, move camshaft as far
rearward as it will go. (2) Zero dial indicator (Fig. 6).
(3) Move as far forward and backward as camshaft
will go. (4) End play travel: 0.025-0.200mm (.001-.008
inch).
LASH ADJUSTER (TAPPET) NOISE
A tappet-like noise may be produced from several
items. See Lash Adjuster and Tappet Noise-DIAG-
NOSIS in STANDARD SERVICE PROCEDURES,
this Group.
VALVE COMPONENTS REPLACEÐCYLINDER HEAD
NOT REMOVED
ROCKER ARM AND HYDRAULIC LASH
ADJUSTER
REMOVAL
(1) Remove valve cover. Refer to procedure previ-
ously outlined in this section.
(2) Remove rocker arm shaft(s) in sequence shown
in (Fig. 6). Slide rocker off the shaft. Keep rocker
arms in order for reassembly.
CAUTION: Check lash adjusters for loose or miss-
ing retainers before continuing service procedure.
(3) Remove hydraulic lash adjuster.
Fig. 5 Measuring Camshaft Lobe Wear
Fig. 6 Checking Camshaft End Play
Fig. 7 Rocker Arm ShaftÐRemoval
Fig. 8 Rocker Arm and Lash Adjuster AssemblyÐRight and Left
Ä 2.2/2.5L ENGINE 9 - 37

CRANKSHAFT SERVICE
CRANKSHAFT MAIN BEARINGS
Bearing caps are not interchangeable and should
be marked at removal to insure correct assembly.
Upper and lower bearing halves are NOT inter-
changeable. Lower main bearing halves of 1, 2, 4 and
5 are interchangeable. Upper main bearing halves of
1, 2, 4 and 5 are interchangeable (Fig. 7).
CRANKSHAFT MAIN JOURNALS
The crankshaft journals should be checked for ex-
cessive wear, taper and scoring. Limits of taper or
out-of-round on any crankshaft journals should be
held to .025mm (.001 inch). Journal grinding should
not exceed .305mm (.012 inch) under the standard
journal diameter. Do NOT grind thrust faces of Num-
ber 3 main bearing. Do NOT nick crank pin or bear-
ing fillets. After grinding, remove rough edges from
crankshaft oil holes and clean out all passages.
CAUTION: With the nodular cast iron crankshafts
used it is important that the final paper or cloth pol-
ish after any journal regrind be in the same direc-
tion as normal rotation in the engine.
Upper and lower Number 3 bearing halves are
flanged to carry the crankshaft thrust loads and are
NOT interchangeable with any other bearing halves
in the engine (Fig. 7). All bearing cap bolts removed
during service procedures are to be cleaned and oiled
before installation. Bearing shells are available in
standard and the following undersized: 0.025mm
(.001 inch), .051mm (.002 inch), .076mm (.003 inch),
.254mm (.010 inch), and .305mm (.012 inch). Never
install an undersize bearing that will reduce clear-
ance below specifications.
MAIN BEARING SERVICEÐCRANKSHAFT NOT REMOVED
REMOVAL
(1) Remove oil pan and identify bearing caps before
removal. (2) Remove bearing caps one at a time. Remove
upper half of bearing by inserting Special Main Bear-
ing Tool C-3059 (Fig. 8) into the oil hole of crankshaft. (3) Slowly rotate crankshaft clockwise, forcing out
upper half of bearing shell.
INSTALLATION Only one main bearing should be selectively
fitted while all other main bearing caps are prop-
erly tightened. When installing a new upper bearing shell, slightly
chamfer the sharp edges from the plain side. (1) Start bearing in place, and insert Main Bearing
Tool C-3059 into oil hole of crankshaft (Fig. 8). (2) Slowly rotate crankshaft counter-clockwise slid-
ing the bearing into position. Remove Special Main
Bearing Tool C-3059.
CHECKING CRANKSHAFT END PLAY
(1) Mount a dial indicator to front of engine, locating
probe on nose of crankshaft (Fig. 9). (2) Move crankshaft all the way to the rear of its
travel. (3) Zero the dial indicator.
(4) Move crankshaft all the way to the front and read
the dial indicator. Refer to (Fig. 10) for specifications.
OPTIONAL CRANKSHAFT END PLAY CHECK
(1) Move crankshaft all the way to the rear of its
travel using a lever inserted between a main bearingFig. 7 Main Bearing Identification
Fig. 8 Removing and Installing Upper Main Bearing With Special Tool C-3059
Ä 2.2/2.5L ENGINE 9 - 43

(Fig. 9) are different, one has end positioning tabs,
while the other is plain. One pairof each thrust
washers are installed into the block and one pair
into the main bearing cap (Fig. 9). (2) Apply a thin film of grease to plain side of
thrust washers and position them on each side of
number three main bearing. Grooved surface towards
crankshaft. (3) Oil the bearings and journals and install crank-
shaft. (4) Install lower main bearing shells without oil
grooves in monoblock cap. (5) Install one pair of thrust washers in cap. Refer
to Thrust Bearings (Fig. 9). (6) Carefully install bearing cap with arrows (Fig.
10) toward timing belt end. (7) Oil the bearing cap bolt threads, install and
tighten bolts progressively in sequence shown in
(Fig. 9) to 80 N Im (60 ft. lbs.) torque.
CHECKING CRANKSHAFT END PLAY
(1) Mount a dial indicator to front of engine, locat-
ing probe on nose of crankshaft (Fig. 11). (2) Move crankshaft all the way to the rear of its
travel. (3) Zero the dial indicator.
(4) Move crankshaft all the way to the front and
read the dial indicator. Refer to (Fig. 6) for specifica-
tion.
CRANKSHAFT OIL SEALS SERVICE
REAR CRANKSHAFT SEAL RETAINER
(1) Install rear crankshaft oil seal in housing with
Special Tool MD998718 (Fig. 12). (2) Apply (Mopar Silicone Rubber Adhesive Seal-
ant or equivalent) to oil seal housing (Fig. 13) per
procedure detailed in form-in-place gasket section in
Standard Service Procedures.
Fig. 9 Install Main Bearings
Fig. 8 Measuring Clearance
9 - 88 3.0L ENGINE Ä

(3) Before removing valves, remove any burrs
from valve stem lock grooves to prevent damage
to the valve guides. Identify valves to insure instal-
lation in original location.
VALVE INSPECTION
(1) Clean valves thoroughly and discard burned,
warped and cracked valves. (2) Measure valve stems for wear. Refer to specifica-
tions (Fig. 19). Valve stems are chrome plated and should not
be polished. (3) Remove carbon and varnish deposits from inside
of valve guides with a reliable guide cleaner. (4) Measure valve stem guide clearance as follows:(a) Install valve into cylinder head so it is 14mm
(.551 inch) off the valve seat. A small piece of hose
may be used to hold valve in place. (b) Attach dial indicator Tool C-3339 to cylinder
head and set it at right angle of valve stem being
measured (Fig. 17). (c) Move valve to and from the indicator. Refer to
specifications (Fig. 19).
Ream the guides for valves with oversized stems if
dial indicator reading is excessive or if the stems are
scuffed or scored. (5) Service valves with oversize stems and over size
seals are available in 0.15mm (.005 inch), 0.40mm,
(.015 inch) and 0.80mm (.030 inch) oversize. Oversize seals must be used with oversize
valves. Reamers to accommodate the oversize valve stem are
as follows:
(6) Slowly turn reamer by hand and clean guide
thoroughly before installing new valve. Do not at-
tempt to ream the valve guides from standard
directly to 0.80mm (.030 inch) Use step procedure
of 0.15mm (.005 inch), 0.40mm (.015 inch) and
0.80mm (.030 inch) so the valve guides may be
reamed true in relation to the valve seat. After
reaming guides, the seat runout should be mea-
sured and resurfaced if necessary. See Refacing
Valves and Valve Seats.
VALVE GUIDES
Replace cylinder head if guide does not clean
up with 0.80mm (.030 inch) oversize reamer, or if
guide is loose in cylinder head.
Fig. 18 Intake and Exhaust Valves
Fig. 19 Valve Guide Specifications
Fig. 16 Compress Valve Springs with Special Tool C-3422B with adapter 6412
Fig. 17 Measuring Valve Guide Wear
Ä 3.3/3.8L ENGINE 9 - 105

The PCM removes the ground to the solenoid when
the engine reaches a specified temperature and the
time delay interval has occurred. When the solenoid is
de-energized, vacuum flows to the canister purge
valve. Vapors are purged from the canister and flow to
the throttle body. The purge solenoid is also energized during certain
idle conditions to update the fuel delivery calibration.
MALFUNCTION INDICATOR LAMP (CHECK
ENGINE)ÐPCM OUTPUT
The Malfunction Indicator lamp (instrument panel
Check Engine lamp) comes on each time the ignition
key is turned ON and stays on for 3 seconds as a bulb
test. The malfunction indicator lamp warns the opera-
tor that the PCM has entered a Limp-in mode. During
Limp-in-Mode, the PCM attempts to keep the system
operational. The malfunction indicator lamp signals
the need for immediate service. In limp-in mode, the
PCM compensates for the failure of certain components
that send incorrect signals. The PCM substitutes for
the incorrect signals with inputs from other sensors. Signals that can trigger the Malfunction Indi-
cator Lamp.
² Coolant Temperature Sensor
² Manifold Absolute Pressure Sensor
² Throttle Position Sensor
² Battery Voltage Input
² An Emissions Related System
² Charging system
The malfunction indicator lamp can also be used to
display diagnostic trouble codes. Cycle the ignition
switch on, off, on, off, on, within five seconds and any
diagnostic trouble codes stored in the PCM will be
displayed. Refer to the 2.2L/2.5L Single Point Fuel
InjectionÐOn-Board Diagnostics section in this group.
DATA LINK CONNECTORÐPCM OUTPUT
The data link connector provides the technician with
the means to connect the DRBII scan tool to diagnosis
the vehicle.
ELECTRIC ELECTRONIC GAS
RECIRCULATIONÐPCM OUTPUT
The electronic exhaust gas recirculation transducer
(EET) is a back pressure transducer/electric vacuum
solenoid assembly (Fig. 13). The EET assembly mounts
above the EGR valve (Fig. 14).
The solenoid turns the vacuum supply to the trans-
ducer on and off. The electric vacuum solenoid portion
of the EET energizes when the PCM provides a ground
path. When the solenoid energizes, vacuum is pre-
vented from flowing to the transducer. When the sole-
noid de-energizes, vacuum flows to the transducer. The
solenoid energizes during engine warm-up, closed
throttle (idle or cruise), wide open throttle, and rapid
acceleration/deceleration. If the solenoid wire con-
nector is disconnected, the EGR valve will oper-
ate at all times.
Fig. 12 EVAP Canister Purge Solenoid
Fig. 13 Electronic EGR Recirculation Transducer
Fig. 14 EGR Valve and Electric EGR Transducer
14 - 30 FUEL SYSTEMS Ä

ter mounting studs (Fig. 12). The top of the solenoid
has the word TOP on it. The solenoid will not oper-
ate unless it is installed correctly.
DATA LINK CONNECTORÐPCM OUTPUT
The data link connector provides the technician
with the means to connect the DRBII scan tool to di-
agnosis the vehicle.
FUEL INJECTORÐPCM OUTPUT
The Fuel Injectors are electric solenoids driven by
the PCM (Fig. 13). Based on sensor inputs, the PCM
determines when and how long the fuel injector
should operate. The amount of time an injector fires
is referred to as injector pulse width. The auto shut-
down (ASD) relay supplies battery voltage to the in-
jector. The PCM supplies the ground path. By
switching the ground path on and off, the PCM ad-
justs injector pulse width.
When the PCM supplies a ground path, a spring
loaded needle or armature lifts from its seat and fuel
flows through the injector orifice. Fuel is constantly supplied to the injector at regu-
lated 380 Kpa (55 psi). Unused fuel returns to the
fuel tank.
GENERATOR FIELDÐPCM OUTPUT
The PCM regulates the charging system voltage
within a range of 12.9 to 15.0 volts. Refer to Group
8A for charging system information.
IDLE AIR CONTROL MOTORÐPCM OUTPUT
The idle speed stepper motor is mounted on the
throttle body and is controlled by the PCM (Fig. 9).
The PCM adjusts engine idle speed through the idle
air control motor to compensate for engine load or
ambient conditions. The throttle body has an air bypass passage that
provides air for the engine at idle (the throttle blade is closed). The idle air control motor pintle protrudes
into the air bypass passage and regulates air flow
through it. The PCM adjusts engine idle speed by moving the
idle air control motor pintle in and out of the bypass
passage. The adjustments are based on inputs the
PCM receives from the throttle position sensor, speed
sensor (distributor pick-up coil), coolant temperature
sensor, and various switch operations (brake, park/
neutral, air conditioning). Deceleration die out is also
prevented by increasing airflow when the throttle is
closed quickly.
IGNITION COILÐPCM OUTPUT
The PCM provides a ground contact (circuit) for en-
ergizing the ignition 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 an input
from the distributor pick-up. Refer to Auto Shutdown
(ASD) Relay/Fuel Pump RelayÐPCM Output in this
section for relay operation. The ignition coil is mounted on the hot box next to
the thermostat housing (Fig. 14).
MALFUNCTION INDICATOR (CHECK ENGINE)
LAMPÐPCM OUTPUT
The malfunction indicator lamp (instrument panel
Check Engine lamp) comes on each time the ignition
key is turned ON and stays on for 3 seconds as a
bulb test. The malfunction indicator lamp warns the
operator that the PCM has entered a Limp-in mode.
During Limp-in-Mode, the PCM attempts to keep the
system operational. The malfunction indicator lamp
signals the need for immediate service. In limp-in
Fig. 13 Fuel Injector
Fig. 14 Ignition Coil
14 - 62 FUEL SYSTEMS Ä