1993 CHEVROLET PLYMOUTH ACCLAIM key

make sure that the spark plugs are firing. Inspect the
distributor rotor, cap, spark plug cables, and spark
plugs. If they are in proper working order, the ignition
system is not the reason why the engine will not start.
Inspect the fuel system and engine for proper opera-
tion.
FAILURE TO START TESTÐ2.5L TBI AND 3.0L
ENGINES
Before proceeding with this test make sure
Testing For Spark At Coil has been performed.
Failure to do this may lead to unnecessary diag-
nostic time and wrong test results.
WARNING: BE SURE TO APPLY PARKING BRAKE
AND/OR BLOCK WHEELS BEFORE PERFORMING
ANY TEST WITH THE ENGINE RUNNING.
(1) Battery voltage must be at least 12.4 volts to
perform test. (2) Crank the engine for 5 seconds while monitoring
the voltage at the coil positive (+) terminal (Fig. 2 or
Fig. 3). If the voltage remains near zero during the
entire period of cranking, refer to Group 14 for On-
Board Diagnostic checks. Also, refer to the DRBII scan
tool and the appropriate Powertrain Diagnostic Proce-
dures manual. These checks will help diagnose prob-
lems with the PCM and auto shutdown relay. (3) If voltage is at near-battery voltage and drops to
zero after 1-2 seconds of cranking, refer to On-Board
Diagnostic in Group 14. Also, refer to the DRBII scan
tool and the appropriate Powertrain Diagnostic Proce-
dures manual. These tests will help check the distribu-
tor reference pickup circuit to the PCM. (4) If voltage remains at near battery voltage during
the entire 5 seconds, with the key off,remove the
PCM 60-way connector. Check the 60-way connector
for any terminals that are pushed out or loose. (5) Remove the connector to coil (+) and connect a
jumper wire between battery (+) and coil (+). (6) Using the special jumper (Fig. 4), momentarily ground terminal #19 of the 60-way connector (Fig.
5). A spark should be generated when the ground is
removed.
(7) If spark is generated, replace the PCM.
(8) If no spark is seen, use the special jumper to
ground the coil (-) terminal directly. (9) If spark is produced, inspect wiring harness for
an open condition.
Fig. 2 Coil TerminalsÐ2.2L TBI, 2.5L TBI and 2.5L MPI Engines
Fig. 3 Coil TerminalsÐ3.0L Engine
Fig. 4 Special Jumper to Ground Coil Negative
Fig. 1 Checking for Spark
8D - 12 IGNITION SYSTEMS Ä

(10) If no spark is produced, replace the ignition coil.
POOR PERFORMANCE TEST
To prevent unnecessary diagnostic time and
possible incorrect results, the Testing For Spark
At Coil procedure should be performed before
this test.
WARNING: APPLY PARKING BRAKE AND/OR BLOCK
THE WHEELS BEFORE PERFORMING ANY ENGINE
RUNNING TESTS.
Check and adjust basic timing (refer to the specifica-
tion section of this group and see service procedures).
COOLANT TEMPERATURE SENSOR TEST
(1) With key off, disconnect wire connector from
coolant temperature sensor (Fig. 6). (2) Connect one lead of ohmmeter to one terminal of
coolant temperature sensor. (3) Connect the other lead of ohmmeter to remaining
terminal of coolant temperature sensor. The ohmmeter
should read as follows;
² Engine/Sensor at normal operating temperature
around 200ÉF should read approximately 700 to 1,000
ohms.
² Engine/Sensor at room temperature around 70ÉF,
ohmmeter should read approximately 7,000 to 13,000
ohms. Refer to On Board Diagnostics in the General
Diagnosis section of Group 14. Also, refer to the
DRBII scan tool and the appropriate Powertrain
Diagnostic Procedures manual for additional
test procedures.
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
TEST
Refer to the DRB II scan tool and appropriate Pow-
ertrain Diagnostic Procedures manual for further test
procedures.
Fig. 5 60-Way Electrical Connector, Powertrain con- trol module
Fig. 6 Coolant Temperature Sensor Test
Ä IGNITION SYSTEMS 8D - 13

(2) Carefully engage distributor drive with gear on
camshaft. When the distributor is installed properly,
the rotor will be in line with previously scribe line on
air intake plenum. If engine was cranked while
distributor was removed, establish proper rela-
tionship between the distributor shaft and Num-
ber 1 piston position as follows: (a) Rotate the crankshaft until number one piston
is at top of compression stroke. (b) Rotate rotor to number one rotor terminal (Fig.
20). (c) Lower the distributor into the opening, engag-
ing distributor drive with drive on camshaft. With
distributor fully seated on engine, rotor should be
under the number 1 terminal (Fig. 20).
(3) Install distributor cap. Ensure sure all high
tension wires are firmly in the cap towers. (4) Install hold-down nut and finger tighten.
(5) Connect distributor electrical connector to wiring
harness connector (Fig. 17). (6) Set ignition timing to specification. Refer to Ig-
nition Timing in this section.
DISASSEMBLY
(1) Remove distributor cap mounting screws (Fig.
18). (2) Remove distributor cap and inspect for flashover,
cracked carbon button, cracked cap, or burned termi-
nals. If any of these conditions exist, replace cap. (3) Remove rotor screw (Fig. 21). Inspect rotor for
cracks or burned electrode. If any of these conditions
exist, replace rotor. (4) Remove protective cover from distributor hous-
ing (Fig. 22). (5) Remove lead wire clamp screw and remove lead
wire (Fig. 23). (6) Remove disk assembly screw (Fig. 24).
(7) Remove disk spacers and disk (Fig. 25). Disk and spacers are keyed. Check disk for warpage,
cracks or damaged slots (Fig. 26). (8) Remove bushing and photo optic sensing unit
fasteners. Remove unit from distributor housing (Fig.
27). (9) Remove bearing retainer screws (Fig. 28).
Fig. 21 Rotor Screw
Fig. 22 Protective Cover
Fig. 23 Lead Wire Clamp
Fig. 20 Distributor Cap Terminal Routing, View from Top of CapÐ3.0L Engine
8D - 20 IGNITION SYSTEMS Ä

(Fig. 4). Secondary resistance should be 11,600 to
15,800 ohms. Replace the coil if resistance is not
within tolerance.
FAILURE TO START TESTÐTURBO III ENGINE
(1) Determine that sufficient battery voltage (12.4
volts nominal) is present for the cranking and igni-
tion systems. (2) Connect a voltmeter to the wiring harness coil
connector at the B+ pin (Fig. 5).
(3) Crank the engine for 5 seconds while monitor-
ing the voltage at the B+ connector terminal. If the
voltage remains near zero during the entire period of
cranking, check the auto shutdown relay and PCM.
Refer to DRBII scan tool and the appropriate Power-
train Diagnostic Procedures manual. Refer to Group
14 for description of On Board Diagnostics. (4) If voltage is at near-battery voltage, and drops
to zero after 1-2 seconds of cranking, check the cam-
shaft position sensor and crankshaft position sensor
and their circuits. Refer to the DRBII scan tool and
the appropriate Powertrain Diagnostic Procedure
manual. Refer to Group 14 for a description of On-
Board Diagnostics. (5) If voltage remains at near-battery voltage dur-
ing the entire 5 seconds, turn the key off, remove the PCM 60-way connector. Check the 60-way for any
terminals loose from the connector (push-out).
TESTING FOR SPARK AT COILÐ3.3L AND 3.8L
ENGINES
WARNING: THE ENGINE DIRECT IGNITION SYSTEM
GENERATES APPROXIMATELY 40,000 VOLTS. PER-
SONAL INJURY COULD RESULT FROM CONTACT
WITH THIS SYSTEM.
The coil pack contains 3 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.
Remove the cable from number 2 spark plug. Insert a
clean spark plug into the spark plug boot, and ground
plug to the engine (Fig. 1). Crank the engine and look for spark across the
electrodes of the spark plug. Repeat the above test for
the five remaining cylinders. If there is no spark
during all cylinder tests, proceed to the failure to start
test. If one or more tests indicate irregular, weak, or no
spark, proceed to Check Coil Test.
WARNING: THE DIRECT IGNITION SYSTEM GENER-
ATES APPROXIMATELY 40,000 VOLTS. PERSONAL
INJURY COULD RESULT FROM CONTACT WITH THIS
SYSTEM.
CHECK COIL TESTÐ3.3L AND 3.8L ENGINES
Coil one fires cylinders 1 and 4, coil two fires
cylinders 2 and 5, coil three fires cylinders three
and six. Each coil tower is labeled with the number of the
corresponding cylinder. (1) Remove the ignition cables and measure the
resistance of the cables. Resistance must be between
3,000 to 12,000 ohms per foot of cable. Replace any
cable not within tolerance. (2) Disconnect the electrical connector from the coil
pack (Fig. 6). (3) Measure the primary resistance of each coil. At
the coil, connect an ohmmeter between the B+ pin and
the pin corresponding to the cylinders in question (Fig.
7). Resistance on the primary side of each coil should be
0.5 - 0.7 ohm. Replace the coil if resistance is not within
tolerance. (4) Remove ignition cables from the secondary tow-
ers of the coil. Measure the secondary resistance of the
coil between the towers of each individual coil (Fig. 8).
Refer to the Coil Specifications Chart in the Specifica-
tions section of this group. Replace the coil if resistance
is not within tolerance.
Fig. 4 Checking Ignition Coil Secondary ResistanceÐTurbo III Engines
Fig. 5 Wiring Harness Coil ConnectorÐTurbo III Engine
8D - 36 IGNITION SYSTEMS Ä

FAILURE TO START TEST
This no-start test checks the camshaft position sen-
sor and crankshaft position sensor. The powertrain control module (PCM) supplies 8.0
volts to the camshaft position sensor and crankshaft
position sensor through one circuit. If the 8.0-volt
supply circuit shorts to ground, neither sensor will
produce 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 PCM de-energizes
the relay within one second because it has not received
a crankshaft position sensor signal indicating engine
rotation.
During cranking, the ASD relay will not energize
until the PCM receives a crankshaft signal. Secondly,
the ASD relay remains energized only if the PCM
senses a camshaft position sensor signal immediately
after detecting the crankshaft 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. 2). (3) Connect a test light to the B+ (battery voltage)
terminal of the coil electrical connector and ground.
The wire for the B+ terminal is dark green with a black
tracer. (4) Turn the ignition key to the ON position.The
test light should flash On and then Off. Do not turn
the Key to off position, leave it in the On position .
(a) If the test light flashes momentarily, the PCM
grounded the auto shutdown (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 DRBII scan tool to test the
ASD relay and circuits. Refer to the appropriate
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 position
before cranking. Wait for the test light to flash once,
then crank the engine. (a) If the test light momentarily flashes during
cranking, the PCM is not receiving a camshaft posi-
tion sensor signal. Use the DRBII scan tool to test the
camshaft position sensor and sensor circuits. Refer to
the appropriate Powertrain Diagnostics Procedure
Manual. Refer to the wiring diagrams section for
circuit information. (b) If the test light did not flash during cranking,
unplug the camshaft position sensor connector. Turn
the ignition key to the off position. Turn the key to
the On position, wait for the test light to momen-
tarily flash once, then crank the engine. If the test
light momentarily flashes, the camshaft position
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 position sensor
8.0-volt supply circuit, or the crankshaft position
sensor 5-volt output or ground circuits. Use the
DRBII scan tool to test the crankshaft position sen-
sor and the sensor circuits.
Fig. 6 Ignition Coil Electrical Connection
Fig. 7 Ignition Coil Terminal Identification
Fig. 8 Checking Ignition Coil Secondary Resistance
Ä IGNITION SYSTEMS 8D - 37

Refer to the appropriate Powertrain Diagnostics Pro-
cedure Manual. Refer to the wiring diagrams section
for circuit information.
COOLANT TEMPERATURE SENSOR TEST
(1) With key off, disconnect wire connector from
coolant temperature sensor (Fig. 9).
(2) Connect one lead of ohmmeter to one terminal of
coolant temperature sensor. (3) Connect the other lead of ohmmeter to remaining
terminal of coolant temperature sensor. The ohmmeter
should read as follows;
² Engine/Sensor hot at normal operating temperature
around 200ÉF should read approximately 700 to 1,000
ohms.
² Engine/Sensor at room temperature around 70ÉF,
ohmmeter should read approximately 7,000 to 13,000
ohms. To test the coolant temperature sensor circuits,
refer to the DRBII scan tool and the appropriate
Powertrain Diagnostic Service manual.
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
TEST
Refer to the appropriate Powertrain Diagnostic Pro-
cedure manual.
CRANKSHAFT POSITION SENSOR AND CAMSHAFT
POSITION SENSOR TESTS
Refer to the appropriate Powertrain Diagnostic Pro-
cedure manual.
Fig. 9 Coolant Temperature Sensor Test
8D - 38 IGNITION SYSTEMS Ä

IGNITION SWITCH
IGNITION SWITCH AND KEY CYLINDER SERVICE
The ignition switch is located on the steering col-
umn. The Key In Switch is located in the ignition
switch module. For diagnosis of the Key In Switch,
refer to Section 8M.
REMOVAL
If the vehicle has a floor mounted gear shifter,
place the selector in the Park position. (1) Disconnect negative cable from battery.
(2) If the vehicle has a tilt column, remove the tilt
lever by turning it counterclockwise. (3) Remove upper and lower covers from steering
column.
(4) Remove ignition switch mounting screws. Use
tamper proof torx bit Snap-on TTXR15A2, TTXR20A2
or equivalent to remove the screws (Fig. 1). (5) Gently pull switch away from the column. Release
connector locks on the 7 terminal wiring connector,
then remove the connector from the ignition switch.
(6) Release connector lock on the 4 terminal con-
nector, then remove the connector from the ignition
switch. (7) To remove the key cylinder from the ignition
switch: (a) Insert key in the ignition switch. Turn the
key to the LOCK position. Using a small screw-
driver, depress the key cylinder retaining pin until
it is flush with the key cylinder surface (Fig. 2). (b) Rotate the key clockwise to the OFF position.
The key cylinder will unseat from the ignition
switch (Fig. 3). When the key cylinder is unseated,
it will be approximately 1/8 inch away from the ig-
nition switch halo light ring. Do not attempt to
remove the key cylinder at this time. (c) With the key cylinder in the unseated posi-
tion, rotate the key counterclockwise to the lock po-
sition and remove the key. (d) Remove key cylinder from ignition switch
(Fig. 4).
INSTALLATION
If the vehicle has a floor mounted gear shifter,
place the selector in the Park position.
IGNITION SWITCH DESIGNATIONS
Fig. 1 Ignition Switch Screw Removal
Fig. 2 Key Cylinder Retaining Pin
Ä IGNITION SYSTEMS 8D - 45

(1) Connect electrical connectors to the ignition
switch. Make sure that the switch locking tabs are fully
seated in the wiring connectors. (2) Before attaching the ignition switch to a tilt
steering column, the transaxle shifter must be in the
Park position. Also the park lock dowel pin and the
column lock flag must be properly indexed before
installing the switch (Fig. 5). (a) Place the transaxle shifter in the PARK posi-
tion. (b) Place the ignition switch in the lock position.
The switch is in the lock position when the column
lock flag is parallel to the ignition switch terminals
(Fig. 5). (c) Position ignition switch park lock dowel pin so
it will engage the steering column park lock slider
linkage (Fig. 6). (d) Apply a light coating of grease to the column
lock flag and the park lock dowel pin.
(3) Place the ignition switch against the lock hous-
ing opening on the steering column. Ensure ignition
switch park lock dowel pin enters the slot in the park
lock slider linkage in the steering column. (4) Install ignition switch mounting screws. Tighten
screws to 2 N Im (17 in. lbs.) torque.
(5) Install steering column covers. Tighten screws to
2N Im (17 in. lbs.) torque.
(6) If the vehicle is equipped with a tilt steering
column, install the tilt lever. (7) To install the ignition key in the lock cylinder:(a) With the key cylinder and the ignition switch
in the Lock position, insert the key cylinder into the
ignition switch until it bottoms. (b) Insert ignition key into lock cylinder. While
gently pushing the key cylinder in toward the igni-
tion switch, rotate the ignition key until to the end of
travel. (c) Connect negative cable to battery.
(8) Check for proper operation of the halo light, shift
lock (if applicable), and column lock. Also check for
proper operation of the ignition switch accessory, lock,
off, run, and start positions.
Fig. 3 Unseated Key Cylinder
Fig. 4 Key Cylinder Removal
Fig. 5 Ignition Switch View From Column
Fig. 6 Ignition Switch Mounting Pad
8D - 46 IGNITION SYSTEMS Ä