1993 CHEVROLET PLYMOUTH ACCLAIM cooling

2.2L TBI, 2.5L TBI, 2.5L MPI AND 3.0L IGNITION SYSTEMSÐSERVICE PROCEDURES
INDEX
page page
Coolant Temperature Sensor ................ 14
Distributor Pick-UpÐ2.2L TBI, 2.5L TBI and 2.5L MPI Engines ....................... 18
Distributor ServiceÐ3.0L Engine ............. 18
DistributorÐ2.2L TBI, 2.5L TBI and 2.5L MPI Engines .............................. 17
Idle RPM TestÐ2.5L and 3.0L Engines ........ 16
Ignition CoilÐ2.2L TBI, 2.5L TBI and 2.5L MPI Engines ....................... 14 Ignition CoilÐ3.0L Engines
................. 15
Ignition Timing ProcedureÐ2.2L TBI, 2.5L TBI, 2.5L MPI, and 3.0L Engines ............... 16
Manifold Absolute Pressure (MAP) Sensor ServiceÐ2.5L TBI and 3.0L Engines ........ 22
Powertrain Control Module (PCM) ............ 14
Spark Plug Service ....................... 15
POWERTRAIN CONTROL MODULE (PCM)
The powertrain control module (PCM) is located
next to the battery (Fig. 1).
REMOVAL
(1) Remove air cleaner duct or air cleaner assem-
bly. (2) Remove battery.
(3) Remove PCM mounting screws.
(4) Remove 60-way wiring connector from the
PCM. (5) Remove PCM.
INSTALLATION
(1) Connect 60-Way electrical connector to PCM
(Fig. 1). (2) Install PCM. Tighten mounting screws.
(3) Install battery.
(4) Install air cleaner duct or air cleaner assembly.
COOLANT TEMPERATURE SENSOR
On 2.2L TBI, 2.5L TBI and 2.5L MPI (flexible fuel
AA-Body) engines, the coolant temperature sensor is
located behind the ignition coil (Fig. 2). On 3.0L en-
gines the sensor is located next to the thermostat
housing (Fig. 3).
REMOVAL
(1) Drain cooling system until coolant level is below
coolant sensor. Refer to Group 7, Cooling System. (2) Disconnect electrical connector from sensor.
(3) Remove sensor from engine.
INSTALLATION
(1) Install coolant sensor. Tighten 2.2L TBI, 2.5L
TBI or 2.5L MPI engine coolant sensor to 28 N Im (20
ft. lbs.) torque. Tighten the 3.0L engine coolant sensor
to7N Im (60 in. lbs.) torque.
(2) Connect electrical connector to sensor.
(3) Fill cooling system. Refer to Group 7, Cooling
System.
IGNITION COILÐ2.2L TBI, 2.5L TBI AND 2.5L MPI
ENGINES
The ignition coil mounts to the thermostat housing
(Fig. 4).
Fig. 1 Powertrain control module (PCM)
Fig. 2 Coolant Temperature SensorÐ2.2 TBI, 2.5L TBI and 2.5L MPI Engines
8D - 14 IGNITION SYSTEMS Ä

SCAVENGER DEPOSITS Fuel scavenger deposits may be either white or yel-
low (Fig. 12). They may appear to be harmful, but
are a normal condition caused by chemical additives
in certain fuels. These additives are designed to
change the chemical nature of deposits and decrease
spark plug misfire tendencies. Accumulation on the
ground electrode and shell area may be heavy but
the deposits are easily removed. Spark plugs with
scavenger deposits can be considered normal in con-
dition and be cleaned using standard procedures.
CHIPPED ELECTRODE INSULATOR A chipped electrode insulator usually results from
bending the center electrode while adjusting the
spark plug electrode gap. Under certain conditions,
severe detonation also can separate the insulator
from the center electrode (Fig. 13). Spark plugs with
chipped electrode insulators must be replaced.
PREIGNITION DAMAGE
Excessive combustion chamber temperature can
cause preignition damage. First, the center electrode
dissolves and the ground electrode dissolves some- what later (Fig. 14). Insulators appear relatively de-
posit free. Determine if the spark plug has the
correct heat range rating for the engine, if ignition
timing is over advanced or if other operating condi-
tions are causing engine overheating. The heat range
rating refers to the operating temperature of a par-
ticular type spark plug. Spark plugs are designed to
operate within specific temperature ranges depend-
ing upon the thickness and length of the center elec-
trode and porcelain insulator.
SPARK PLUG OVERHEATING
Overheating is indicated by a white or gray center
electrode insulator that also appears blistered (Fig.
15). The increase in electrode gap will be consider-
ably in excess of 0.001 in per 1000 miles of operation.
This suggests that a plug with a cooler heat range
rating should be used. Over advanced ignition tim-
ing, detonation and cooling system malfunctions also
can cause spark plug overheating.
CAMSHAFT POSITION SENSOR
The camshaft position sensor provides fuel injection
synchronization and cylinder identification informa-
Fig. 12 Scavenger Deposits
Fig. 13 Chipped Electrode Insulator
Fig. 14 Preignition Damage
Fig. 15 Spark Plug Overheating
8D - 28 IGNITION SYSTEMS Ä

The coil's low primary resistance allows the PCM to
fully charge the coil for each firing.
COOLANT TEMPERATURE SENSOR
On 2.2L Turbo III engines, the coolant temperature
sensor is installed into the thermostat housing (Fig. 30).
On 3.3L and 3.8L engines, the coolant temperature sensor
is located next to the thermostat housing (Fig. 31).
The coolant temperature sensor provides an input
voltage to the powertrain control module (PCM). The
sensor is a variable resistance (thermistor) with a
range of -40ÉC to 130ÉC (-40ÉF to 265ÉF). As coolant
temperature varies, the sensor resistance changes,
resulting in a different input voltage to the PCM.
The PCM contains different spark advance schedules
for cold and warm engine operation. The schedules reduce
engine emission and improve driveability.
The PCM demands slightly richer air-fuel mixtures
and higher idle speeds until the engine reaches normal
operating temperature. The coolant sensor input is also used for cooling
fan control.
KNOCK SENSORÐTURBO III ENGINE
Turbo III engines use a knock sensor. The sensor gen-
erates a signal when spark detonation occurs in the
combustion chambers. The sensor is mounted on the in-
take manifold behind the PCV breather (Fig. 32). The
sensor provides input voltage used by the powertrain
control module (PCM) to modify spark advance and
boost schedules in order to eliminate detonation.
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 output voltage to change.
The change in MAP sensor output voltage results in
a different input voltage to the PCM.
The input voltage level supplies the PCM with infor-
mation relating to ambient barometric pressure during
engine start-up (cranking) and engine load while its op-
erating. The PCM uses this input along with inputs
from other sensors to adjust air-fuel mixture.
On Turbo III engines, the MAP sensor is mounted
to the front right fender (Fig. 33) On 3.3L and 3.8L
engines, the MAP sensor (Fig. 34) is mounted to the
side of the intake manifold, below the positive crank-
case ventilation (PCV) valve. The sensor is connected
to the PCM electrically.
AUTO SHUTDOWN (ASD) RELAY AND FUEL PUMP
RELAY
The powertrain control module (PCM) operates the
auto shutdown (ASD) relay and fuel pump relay
through one ground path. The PCM operates the re-
lays by switching the ground path on and off. Both
relays turn on and off at the same time.
Fig. 32 Knock SensorÐTurbo III Engine
Fig. 30 Coolant Temperature SensorÐTurbo III En- gines
Fig. 31 Coolant Temperature SensorÐ3.3L and 3.8LEngines
8D - 32 IGNITION SYSTEMS Ä

2.2L TURBO III, 3.3L AND 3.8L IGNITION SYSTEMSÐSERVICE PROCEDURES INDEX
page page
Camshaft Position Sensor ServiceÐTurbo III Engine.42Camshaft Position SensorÐ3.3L and 3.8L Engines.43
Coolant Temperature SensorÐ3.3L and 3.8L Engines .............................. 39
Coolant Temperature SensorÐTurbo III ........ 39
Crankshaft Position SensorÐ3.3L and 3.8L Engines.42
Crankshaft Position SensorÐTurbo III Engine . . . 42
Idle RPM Test ........................... 41
Ignition Coil ServiceÐTurbo III Engine ........ 43 Ignition CoilÐ3.3L and 3.8L Engine
........... 43
Knock SensorÐTurbo III Engines ............ 40
Manifold Absolute Pressure (MAP) SensorÐ3.3L and 3.8L Engines ....................... 44
Manifold Absolute Pressure (MAP) SensorÐ Turbo III Engine ........................ 44
Powertrain Control Module (PCM) ............ 39
Spark Plug Cable Service .................. 40
Spark Plug Service ....................... 41
POWERTRAIN CONTROL MODULE (PCM)
REMOVAL
(1) Remove air cleaner duct or air cleaner assem-
bly. (2) Remove battery.
(3) Remove powertrain control module (PCM)
mounting screws (Fig. 1). (4) Remove 60-way connector from PCM. Remove
PCM.
INSTALLATION
(1) Connect 60-Way connector to PCM (Fig. 1).
(2) Install PCM on inside left front fender. Install
and tighten mounting screws. (3) Install the battery.
(4) Install air cleaner duct or air cleaner assembly.
COOLANT TEMPERATURE SENSORÐTURBO III
The coolant sensor threads into the thermostat
housing (Fig. 2).
REMOVAL
(1) Drain cooling system until coolant level is be-
low thermostat housing. Refer to Group 7, Cooling
System. (2) Remove air cleaner fresh air duct.
(3) Disconnect electrical connector from coolant
sensor. (4) Remove sensor from thermostat housing (Fig.
2).
INSTALLATION
(1) Install sensor. Tighten to 7 N Im (60 in. lbs.)
torque. (2) Connect electrical connector to coolant sensor
(3) Fill cooling system. Refer to Group 7, Cooling
System. (4) Install fresh air duct.
COOLANT TEMPERATURE SENSORÐ3.3L AND
3.8L ENGINES
The coolant temperature sensor is located below
the ignition coil (Fig. 3).
REMOVAL
(1) Drain cooling system until coolant level is be-
low coolant sensor. Refer to Group 7, Cooling System. (2) Remove electrical connector from coil (Fig. 4).
(3) Remove coil mounting screws.
(4) Rotate coil away from coolant temperature sen-
sor.
Fig. 1 Powertrain Control Module (PCM)
Fig. 2 Coolant Temperature SensorÐTurbo III
Ä IGNITION SYSTEMS 8D - 39

(5) Disconnect electrical connector from coolant
temperature sensor. (6) Remove sensor from engine.
INSTALLATION
(1) Tighten the coolant sensor to 7 N Im (60 in. lbs.)
torque. (2) Connect electrical connector to sensor.
(3) Fill cooling system. Refer to Group 7, Cooling
System. (4) Install coil. Tighten coil mounting screws to 12
N Im (105 in. lbs.) torque.
(5) Connect electrical connector to coil.
KNOCK SENSORÐTURBO III ENGINES
The knock sensor is located on the intake manifold,
behind the PCV breather (Fig. 5).
REMOVAL
(1) Remove PCV breather.
(2) Remove harness connector from the knock sen-
sor. (3) Remove knock sensor.
INSTALLATION
(1) Install knock sensor. Tighten sensor to 9 N Im
(7 ft. lbs) torque. (2) Connect harness connector to sensor.
(3) Install PCV breather.
SPARK PLUG CABLE SERVICE
Clean high tension cables with a cloth moistened
with a non-flammable solvent. Wipe the cables dry.
Check for brittle or cracked insulation. When testing cables for punctures and cracks with
an oscilloscope, follow the instructions of the equip-
ment manufacturers.
CAUTION: Do not leave any one spark plug cable
disconnected any longer than necessary during test
or possible heat damage to catalytic converter will
occur. Total test time must not exceed ten minutes. If an oscilloscope is not available, cables can be
tested as follows: (1) With the engine not running, connect one end
of a test probe to a good ground. Use a probe made of
insulated wire and insulated alligator clips on each
end.
WARNING: THE ENGINE DIRECT IGNITION SYSTEM
GENERATES APPROXIMATELY 40,000 VOLTS.
PERSONAL INJURY COULD RESULT FROM CON-
TACT WITH THIS SYSTEM.
Fig. 3 Coolant Temperature SensorÐ3.3L and 3.3L Engine
Fig. 4 Ignition Coil Removal
Fig. 5 Knock SensorÐTurbo III Engine
8D - 40 IGNITION SYSTEMS Ä

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

Flexible fuel vehicles can operate on a mixture of
up to 85 percent methanol, 15 percent unleaded gas-
oline. These vehicles also operate on mixtures con-
taining a lower percentage of methanol or just pure
unleaded gasoline. Engine components which are required for safe op-
eration using fuel containing methanol alcohol are
identified by a standard green color and/or display
the statement methanol compatible imprinted on the
component. To ensure continued safe operation, these
components must be serviced only with genuine MO-
PAR replacement parts. Methanol compatible parts for the 2.5L FFV (Flex-
ible Fuel Vehicle) engine include, but are not limited
to; the valve stem oil seals, all piston rings, the oil
fill cap, the fuel injectors, fuel rail, fuel pressure reg-
ulator, hoses and the vacuum control harness hose. BLOCK: All four cylinder cast iron blocks have
cast-in recesses in the bottom of each cylinder bore to
provide connecting rod clearance; especially needed
for 2.5L engines. The bores are also siamese to min-
imize engine length. A coolant passage is drilled
cross-ways through the siamese section to enhance
between the bore cooling on some engine types. A
partial open deck is used for cooling and weight re-
duction with oil filter, water pump, and distributor
mounting bosses molded into the front (radiator side)
of the block. Nominal wall thickness is 4.5 mm. Five
main bearing bulkheads and a block skirt extending
3 mm below the crankshaft center line add to the
blocks high rigidity with light weight. CRANKSHAFT: A nodular cast iron crankshaft is
used in TBI engines. A forged steel crankshaft is
used in the Turbo III engine. All engines have 5 main bearings, with number 3 flanged to control
thrust. The 60 mm diameter main and 50 mm diam-
eter crank pin journals (all) have undercut radiuses
fillets that are deep rolled for added strength. To op-
timize bearing loading 4 counterweights are used.
Hydrodynamic seals (installed in diecast aluminum
retainers) provide end sealing, where the crankshaft
exits the block. Anaerobic gasket material is used for
retainer-to-block sealing. No vibration damper is
used. A sintered iron (TBI engine and steel billet
Turbo III engines) timing belt sprocket is mounted
on the crankshaft nose. This sprocket provides mo-
tive power; via timing belt to the camshaft and inter-
mediate shaft sprockets (also sintered iron (TBI
engine and steel billet Turbo III engines) providing
timed valve, distributor, and oil pump actuation. PISTONS: Some Chrysler pistons have cast-in
steel struts at the pin bosses for autothermic control.
All 2.2L and 2.5L piston tops have cuts to provide
valve clearance. Some pistons are dished to provide
various compression ratios. Standard 2.2L and 2.5L
engines are designed for 9.5:1 and 8.9:1 compression
ratios respectively. The 2.5L piston is dished and is a
lightweight design to enhance engine smoothness.
The 2.2L turbo III uses dished pistons providing a
8.3:1 compression ratio. All standard 2.2/2.5L and
2.5L FFV engines use pressed-in piston pins to at-
tach forged steel connecting rods, 2.2L turbo III en-
gine uses a full floating piston pin and connecting
rod assembly. PISTONS RINGS: The 2.2/2.5L engines share
common piston rings throughout, including molybde-
num filled top ring for reliable compression sealing
and a tapered faced intermediate ring for additional
cylinder pressure control. The 2.5L FFV engine fea-
ture all chrome rings for enhanced long term dura-
bility under multi-fueled conditions. CYLINDER HEAD: The cylinder head is cast alu-
minum with in-line valves. The 2.2/2.5L and 2.5L
FFV valves are arranged with alternating exhaust
and intake. The intake and exhaust ports are located
in the rearward, facing side of the head. The Turbo
III valves are arranged in two inline banks, with the
ports of the bank of two intake valves per cylinder
facing toward the radiator side of engine and ports of
the bank of two exhaust valve per cylinder facing to-
ward the dash panel. The intake ports feed fast-burn
design combustion chambers (2.2/2.5L and 2.5L FFV
only) with the spark plug located close to the center
line of the combustion chamber for optimum effi-
ciency. An integral oil gallery within the cylinder
head supplies oil to the hydraulic lash adjusters,
camshaft, and valve mechanisms. CAMSHAFT: The nodular iron camshaft has five
bearing journals (2.2/2.5L and 2.5L FFV). The Turbo
III employs dual camshafts that have nine bearing
journals. Flanges at the rear journal control cam-
Fig. 1 Engine Identification
Ä 2.2/2.5L ENGINE 9 - 9

² Drive shaft distress: See Driveshafts in Suspension,
Group 2.
² Any front end structural damage (after repair).
² Insulator replacement.
ENGINE MOUNT INSULATOR ADJUSTMENT
(1) Remove the load on the engine motor mounts by
carefully supporting the engine and transmission as-
sembly with a floor jack. (2) Loosen the right engine mount insulator vertical
fasteners, and the front engine mount bracket to front
crossmember screws and nuts. Left engine mount insulator is sleeved over
shaft and long support bolt to provide lateral
movement adjustment with engine weight re-
moved or not. (3) Pry the engine right or left as required to achieve
the proper drive shaft assembly length. See Drive
Shaft in Suspension Group 2 for driveshaft identifica-
tion and related assembly length measuring. (4) Tighten right engine mount insulator vertical
bolts to 68 N Im (50 ft. lbs.). Then tighten front engine
mount screws and nuts to 54 N Im (40 ft. lbs.) and
center left engine mount insulator. (5) Recheck drive shaft length.
ENGINE ASSEMBLY
REMOVAL
(1) Disconnect battery.
(2) Scribe hood hinge outline on hood and remove
hood. (3) Drain cooling system.
(4) Remove hoses from radiator and engine.
(5) Remove radiator and fan assembly.
(6) Remove air cleaner and hoses.
(7) Remove air conditioning compressor mounting
bolts and set compressor aside, if equipped. (8) Remove power steering pump mounting bolts
and set pump aside (9) Remove oil filter.
(10) Disconnect fuel line, heater hose and acceler-
ator cable. (11) Disconnect all electrical connections and har-
nesses at throttle body and engine. (12) Manual Transmission
(a) Disconnect clutch cable.
(b) Remove transmission case lower cover.
(c) Disconnect exhaust pipe at manifold.
(d) Disconnect starter and lay aside.
(e) Install transmission holding fixture.
(13) Automatic Transmission
(a) Disconnect exhaust pipe at manifold.
(b) Disconnect starter and lay aside.
(c) Remove transmission case lower cover.
(d) Mark flex plate to torque converter.
(e) Remove screws holding torque converter to
flex plate.
(14) Attach C clamp on front bottom of torque con-
verter housing to prevent torque converter from com-
ing out. (15) Install transmission holding fixture.
(16) Remove right inner splash shield (Fig. 5).
(17) Remove ground strap.
(18) To lowerengine separate right engine
bracket from yoke bracket To raiseengine remove
long bolt through yoke and insulator. IF INSULA-
TOR TO RAIL SCREWS ARE TO BE REMOVED,
MARK INSULATOR POSITION ON SIDE RAIL TO
INSURE EXACT INSTALLATION (Fig. 4). (19) Remove transmission case to cylinder block
mounting screws.Fig. 5 Right Inner Splash Shield
Fig. 4 Left Insulator Movement
Ä 2.2/2.5L ENGINE 9 - 13