1993 CHEVROLET DYNASTY checking oil

(c) If there is voltage or ground, check cluster for
distorted terminals. If terminals are OK, replace
printed circuit board.
(3) When testing temperature and oil pressure
gauges allow the engine to run until the vehicle
reaches a normal operating temperature. Turn igni-
tion OFF, and remove gauge from cluster. (a) Testing oil pressure gauge, engine needs to
be running. (b) Measure and record the resistance between
sending unit pin and ground pin of the gauge in
question. Refer to Gauge Calibration. (c) When checking temperature and oil pressure
gauges, it is important to have the same engine
temperature and speed when noting gauge position.
The time between gauge reading and measuring
should be kept to a minimum. (d) If resistance and gauge position are not sim-
ilar, replace gauge. (e) If OK, test resistance from the sending unit
to the cluster connector. (f) If resistance reading is different, check
printed circuit board for contact to cluster. (g) If OK and contacts are not distorted, replace
printed circuit board. (h) If everything checks out OK, refer to Sending
Unit Test.
(4) If fuel gauge meets specifications check fuel
tank and original fuel tank sending unit as follow: (a) Carefully remove fuel tank sending unit from
tank.
Fig. 16 Printed Circuit Board
Fig. 17 Fuel Gauge Pins
Fig. 18 Voltmeter Pins
Fig. 19 Temperature Gauge Pins
Fig. 20 Oil Pressure Gauge Pins
Ä INSTRUMENT PANEL AND GAUGES 8E - 29

(b) Refer to sending unit removal Group 14, Fuel.
(c) Connect sending unit wire and jumper wire
as described in the test procedure.
(5) If fuel gauge now checks within specifications,
original sending unit is electrically okay, check fol-
lowing as a possible cause: (a) Ground wire from sending unit to left side
cowl for continuity. (b) Sending unit deformed. Make sure sending
unit float arm moves freely and pick up tube is not
bent upwards creating an interference with bottom
of tank and inspect float. (c) Sending unit improperly installed. Install
properly. (d) Mounting flange on fuel tank for sending
unit deformed. Feel for interference fit of sending
unit to bottom of tank. It is permissible to bend
pick up tube down a little near mounting flange to
gain interference fit. (e) Fuel tank bottom deformed, causing improper
positioning of sending unit pick up tube. Replace or
repair tank and recheck sending unit.
GAUGE CALIBRATION
(1) Remove the gauge.
(2) Check for ignition voltage and ground to the
gauge. (3) With the ignition key in the OFF position, re-
place gauge. Turn the ignition key to the ON posi-
tion. To test oil pressure gauge engine must be
running. When testing oil or temperature gauge the
engine should be at normal operating temperature.
Record the gauge position. (4) Remove gauge and record the resistance be-
tween the sending unit pin and the gauge ground
pin. When checking gauges, it is important to have
the same engine temperature and speed when noting
gauge position. The time between gauge reading and
measuring should be kept to a minimum. (5) The resistance Chart (Fig. 21), is general
guidelines for checking the gauge position against
the sending unit resistance. Because of only a few specific points of gauge posi-
tion versus sending unit resistance, a good estimate
is need when the resistance falls between gradua-
tions. Even when the resistance corresponds to grad-
uations, the gauge has a tolerance of 64 ohms.
Volt gauge: The calibration dot on the volt gauge
corresponds to 13 volts between the gauge ignition
and ground pins. If voltage varies from this, estimate
proper gauge position with input voltage.
VOLTMETER REPLACEMENT
(1) Remove cluster bezels and mask (Fig. 22).
(2) Remove screws attaching gauge assembly to
cluster. (3) Pull rearward to disengage gauge from gauge
pins. (4) For installation reverse above procedures.
OIL PRESSURE GAUGE REPLACEMENT
(1) Remove cluster bezels and mask/lens (Fig. 22).
(2) Remove screws attaching gauge assembly to
cluster.
(3) Pull rearward to disengaged gauge from gauge
pins.
(4) For installation reverse above procedures.
FUEL AND TEMPERATURE GAUGE ASSEMBLY REPLACEMENT
(1) Remove cluster bezel and mask/lens (Fig. 22).
(2) Remove oil pressure gauge.
(3) Remove screws attaching gauge assembly to
cluster.
(4) Pull rearward to disengage gauge from gauge
pins.
(5) For installation reverse above procedures.
SPEEDOMETER SYSTEM
AC body vehicles are equipped with electronically
driven speedometer and odometer assemblies. The unit
has the same appearance as a conventional speedometer
but it eliminates the cable-driven mechanical system. A
signal is sent from a transmission-mounted vehicle
speed sensor to the speedometer circuitry through the
wiring harness. By eliminating the speedometer cable,
instrument cluster service and removal is improved. Re-
fer to Fig. 23 Speedometer Diagnosis Chart. When the speedometer is out of calibration. The elec-
tronic automatic transaxle vehicle speed sensor output
must be calibrated to reflect the different combinations
of equipment. The procedure is called Pinion Factor, re-
fer to Group 21, Transaxle for the procedure.
Fig. 21 Gauge Resistance
8E - 30 INSTRUMENT PANEL AND GAUGES Ä

(3) When testing temperature and oil pressure
gauge, allow the engine to run until the vehicle
reaches a normal operating temperature. Turn igni-
tion OFF, and remove gauge from cluster. (a) Testing oil pressure gauge, engine needs to
be running. (b) Measure and record the resistance between
sending unit pin and ground pin of the gauge in
question. Refer to Gauge Resistance (Fig. 12). (c) When checking temperature and oil pressure
gauges, it is important to have the same engine
temperature and engine speed when noting gauge
position. Therefore, time between noting gauge po-
sition and sending unit measuring should be kept
to a minimum. (d) If resistance and gauge position are not sim-
ilar, replace gauge. (e) If OK, measure the resistance between the
sending unit pin in question and the ground pin at
the cluster wire harness connectors.
Fig. 8 Fuel Gauge Pins
Fig. 9 Voltmeter Pins
Fig. 10 Temperature Gauge Pins
Fig. 11 Oil Pressure Gauge Pins
Ä INSTRUMENT PANEL AND GAUGES 8E - 45

(f) If there is a difference in readings, check
printed circuit board for contact to cluster connec-
tors. (g) If OK and contacts are not distorted, replace
printed circuit board. (h) If everything checks out OK, refer to Sending
Unit Test.
(4) The Gauge Resistance Chart (Fig. 12), is gen-
eral guidelines for checking the gauge position
against the sending unit resistance. Because of only
a few specific points of gauge position versus sending
unit resistance, a good estimate is needed when the
resistance falls between graduations. Even when the
resistance corresponds to graduations, the gauge has
a tolerance of 64 ohms.
Volt gauge: The calibration dot on the volt gauge
corresponds to 13 volts between the gauge ignition
and ground pins. If voltage varies from this, estimate
proper gauge position with input voltage.
TACHOMETER AND TURBO GAUGE REMOVAL
(1) Remove switch pod assembly.
(2) Remove steering column trim cover.
(3) Remove cluster mask and lens assembly.
(4) Remove screws attaching tachometer to cluster
housing. (5) Pull tachometer rearward to remove.
(6) Disconnect turbo gauge hose. If turbo hose can-
not be disconnected, remove cluster. (7) For installation reverse above procedures.
TACHOMETER CIRCUIT TESTING
(1) Remove cluster. (2) Check for battery voltage at cavity 8 of the in-
strument cluster red connector (Fig.6). (3) With the ignition in the ON position, check for
battery voltage at cavity 9 of the instrument cluster
red connector. (4) Check cavity 14 of the instrument cluster red
connector for continuity to ground. (5) Check for tachometer signal from the power-
train control module by connecting an AC DIGITAL
VOLTMETER to cavity 6 of the instrument cluster
black connector and ground. A reading of at least 1.0
volt should be present with the engine running (Fig.
7). (a) If voltage is within specification, go to step 7.
(b) If voltage is NOT within specification, per-
form steps 6.
(6) If there is less than 1.0 volt at cavity 6, check
for continuity between cavity 6 and pin 43 of the
powertrain control module connector. (a) If continuity is OK, between cavity 6 and pin
43 of the powertrain control module connector, re-
place the powertrain control module. (b) No continuity check the connectors for dam-
aged pins or terminal push outs or defective wire.
(7) If all tests performed test good replace the ta-
chometer drive module. (8) If the tachometer continues to be inoperative,
replace the tachometer assembly.
VOLTMETER, TEMPERATURE GAUGE, OIL PRESSURE GAUGE AND FUEL GAUGEASSEMBLYÐREMOVAL
(1) Remove pod switch assembly.
(2) Remove steering column trim cover.
(3) Remove cluster mask and lens assembly.
(4) Remove screws attaching gauge assembly to
cluster. (5) Pull rearward to remove gauge assembly.
(6) For installation reverse above procedures.
SENDING UNIT TEST
It is not necessary to remove instrument clus-
ter from vehicle for gauge replacement. When removing gauge assemblies from cluster,
gauge must be pulled straight out, not twisted, or
damage to gauge pin may result. When a problem occurs with a cluster gauge, be-
fore disassembling the cluster to check the gauge,
check for a defective sending unit or wiring. (1) Sending units and wiring can be checked by
grounding the connector leads, at the sending unit,
in the vehicle. (2) With the ignition in the ON position; a
grounded input will cause the oil, fuel or tempera-
ture gauge to read at or above maximum.
Fig. 12 Gauge Resistance
8E - 46 INSTRUMENT PANEL AND GAUGES Ä

(5) Reconnect battery.
GAUGES
CAUTION: During the removal and installation
watch overlays are not damage.
It is not necessary to remove instrument cluster
from vehicle for gauge replacement. When removing gauge assemblies from cluster,
gauge must be pulled straight out, not twisted, or
damage to gauge pins may result.
MULTIPLE GAUGE INOPERATIVE
Volt, speedometer, tachometer and other gauges
appear to malfunction. Also check warning indicator
lamps: (1) Remove cluster
(2) Check for ignition voltage at pin E of the red
connector. If no voltage, repair as necessary (Fig. 8). (3) Check for ground continuity between pin C of
the gray connector. If no ground, repair as necessary. (4) If voltage and ground OK and pins or connec-
tors are not distorted, replace printed circuit board. (5) Install cluster.
SINGLE GAUGE INOPERATIVE (FIG. 9 AND10)
(1) Remove gauge in question. (2) With the ignition key ON, check for ignition
voltage at ignition pin of gauge. Check for ground at
ground pin of gauge. (a) If no voltage or ground, remove cluster and
check pin E red connector for ignition voltage or
pin C gray connector for ground (Fig. 8). (b) If no voltage or ground, repair as necessary.
Refer to 8W, Wiring Diagrams. (c) If there is voltage or ground, check cluster for
distorted terminals. If terminals are OK, replace
printed circuit board.
(3) When testing the temperature gauge, allow the
engine to run until the vehicle reaches a normal op-
erating temperature. Turn ignition OFF and remove
gauge from cluster.
² When checking the temperature and oil pressure
gauges, it is important to have the same engine tem-
perature and engine speed when noting gauge posi-
tion.
² The time between gauge position reading and
sending unit measuring should be kept to a mini-
mum.
² When testing oil pressure gauge, engine needs to
be running. (a) Measure and record the resistance between
sending unit pin and ground pin of the gauge in
question. Refer to Gauge Calibration.
Fig. 7 Upper Instrument Panel Components
Ä INSTRUMENT PANEL AND GAUGES 8E - 61

(f) If everything checks out OK, refer to Sending
Unit Test.
(4) With the ignition switch in the ON position,
check for battery voltage across the ignition pin and
the ground pin. (5) If fuel gauge meets specifications check fuel
tank and original fuel tank sending unit as follows: (a) Carefully remove fuel tank sending unit from
tank. (b) Refer to sending unit removal Group 14,
Fuel. (c) Connect sending unit wire and jumper wire
as described in the test procedure.
(6) If fuel gauge now checks within specifications,
original sending unit is electrically okay, check fol-
lowing as a possible cause: (a) Ground wire from sending unit to left side
cowl for continuity. (b) Sending unit deformed. Make sure sending
unit float arm moves freely and pick up tube is not
bent upwards creating an interference with bottom
of tank and inspect float. (c) Sending unit improperly installed. Install
properly. (d) Mounting flange on fuel tank for sending
unit deformed. Feel for interference fit of sending
unit to bottom of tank. It is permissible to bend
pick up tube down a little near mounting flange to
gain interference fit. (e) Fuel tank bottom deformed, causing improper
positioning of sending unit pick up tube. Replace or
repair tank and recheck sending unit.GAUGE CALIBRATION
(1) Remove the gauge.
(2) Check for ignition voltage and ground to the
gauge. (3) With the ignition key in the OFF position, re-
place gauge. Turn the ignition key to the ON posi-
tion. To test oil pressure gauge engine must be
running. When testing oil or temperature gauge the
engine should be at normal operating temperature.
Record the gauge position. (4) Remove gauge and record the resistance be-
tween the sending unit pin and the gauge ground
pin. When checking gauges, it is important to have
the same engine temperature and speed when noting
gauge position. The time between gauge reading and
measuring should be kept to a minimum. (5) Resistance Chart (Fig. 11), is general guide-
lines for checking the gauge position against the
sending unit resistance. Because of only a few specific points of gauge posi-
tion versus sending unit resistance, a good estimate
is needed when the resistance falls between gradua-
tions. Even when the resistance corresponds to grad-
uations, the gauge has a tolerance of 64 ohms.
Volt gauge: The calibration dot on the volt gauge
corresponds to 13 volts between the gauge ignition
and ground pins. If voltage varies from this, estimate
proper gauge position with input voltage.
FUEL GAUGE REPLACEMENT
(1) Remove instrument cluster bezel.
(2) Remove mask and lens.
(3) If equipped with tachometer, remove three re-
taining screws and pull the tach straight back.
Fig. 10 Instrument Cluster Without Tachometer
Ä INSTRUMENT PANEL AND GAUGES 8E - 63

scuffing, scoring or scratches. Usually a few strokes
will clean up a bore and maintain the required limits.(2) Deglazing of the cylinder walls may be done
using a cylinder surfacing hone, Tool C-3501, equipped
with 280 grit stones (C-3501-3810) if the cylinder bore
is straight and round. 20-60 strokes depending on the
bore condition will be sufficient to provide a satisfac-
tory surface. Inspect cylinder walls after each 20
strokes. Using a light honing oil available from major
oil distributors. Do not use engine or transmission
oil, mineral spirits or kerosene. (3) Honing should be done by moving the hone up
and down fast enough to get a cross-hatch pattern.
When hone marks intersectat 50-60 degrees, the
cross hatch angle is most satisfactory for proper seat-
ing of rings (Fig. 1).
(4) A controlled hone motor speed between 200-300
RPM is necessary to obtain the proper cross-hatch
angle. The number of up and down strokes per minute
can be regulated to get the desired 50-60 degree angle.
Faster up and down strokes increase the cross-hatch
angle. (5) After honing, it is necessary that the block be
cleaned again to remove all traces of abrasive.
CAUTION: Be sure all abrasive are removed from
engine parts after honing. It is recommended that a
solution of soap and hot water be used with a brush
and the parts then thoroughly dried. The bore can be
considered clean when it can be wiped clean with a
white cloth and cloth remains clean. Oil the bores
after cleaning to prevent rusting.
MEASURING MAIN BEARING CLEARANCE AND
CONNECTING ROD BEARING CLEARANCE
PLASTIGAGE METHOD
Engine crankshaft bearing clearances can be deter-
mined by use of Plastigage or equivalent. The follow-
ing is the recommended procedure for the use of
Plastigage: (1) Remove oil film from surface to be checked.
Plastigage is soluble in oil. (2) The total clearance of the main bearingscan
only be determined by removing the weight of the
crankshaft. This can be accomplished by either of
two methods: PREFERRED METHOD Ð Shimming the bear-
ings adjacent to the bearing to be checked in order to
remove the clearance between upper bearing shell
and the crankshaft. This can be accomplished by
placing a minimum of 0.254mm (.010 inch) shim (e.
g. cardboard, matchbook cover, etc.) between the
bearing shell and the bearing cap on the adjacent
bearings and snugging bolts to 14-20 N Im (10-15
ft.lb.)
² When checking #1 main brg shim #2 main brg
²
When checking #2 main brg shim # 1 & 3 main brg
²When checking #3 main brg shim #2 & 4 main brg
²When checking #4 main brg shim #3 & 5 main brg
²When checking #5 main brg shim #4 main brg
Fig. 2 Plastigage Placed in Lower Shell
Fig. 3 Clearance Measurement
Fig. 1 Cylinder Bore Cross-Hatch Pattern
Ä ENGINE 9 - 3

REMOVE ALL SHIMS BEFORE REASSEM-
BLING ENGINE ALTERNATIVE METHOD Ð With the weight of
the crankshaft being supported by a jack under the
counterweight adjacent to the bearing being checked. (3) Place a piece of Plastigage across the entire
width of the bearing shell in the cap approximately
6.35 mm (1/4 inch) off center and away from the oil
holes (Fig. 2). (In addition, suspect areas can be
checked by placing the Plastigage in the suspect area).
Torque the bearing cap bolts of the bearing being
checked to the proper specifications. (4) Remove the bearing cap and compare the width
of the flattened Plastigage (Fig. 3) with the metric scale
provided on the package. Locate the band closest to the
same width. This band shows the amount of clearance
in thousandths of a millimeter. Differences in readings
between the ends indicate the amount of taper present.
Record all readings taken. Refer to Engine Specifica-
tions. Plastic-Gage generally is accompanied by
two scales. One scale is in inches, the other is a
metric scale. (5) Plastigage is available in a variety of clearance
ranges. The 0.025-0.076mm (.001-.003 inch) is usually
the most appropriate for checking engine bearing
proper specifications.
CONNECTING ROD BEARING CLEARANCE
Engine crankshaft bearing clearances can be deter-
mined by use of Plastigage or equivalent. The following
is the recommended procedure for the use of Plasti-
gage: (1) Rotate the crankshaft until the connecting rod to
be checked is at the bottom of its stroke. (2) Remove oil film from surface to be checked.
Plastigage is soluble in oil. (3) Place a piece of Plastigage across the entire
width of the bearing shell in the bearing cap approxi-
mately 6.35 mm (1/4 inch.) off center and away from
the oil hole (Fig. 2). In addition, suspect areas can be
checked by placing plastigage in the suspect area. (4) Before assembling the rod cap with Plastigage in
place, the crankshaft must be rotated until the con-
necting being checked starts moving toward the top of
the engine. Only then should the cap be assembled and
torqued to specifications. Do not rotate the crank-
shaft while assembling the cap or the Plastigage
may be smeared, giving inaccurate results. (5) Remove the bearing cap and compare the width
of the flattened Plastigage (Fig. 3) with the metric
scale provided on the package. Locate the band closest
to the same width. This band shows the amount
of clearance in thousandths of a millimeter. Differences
in readings between the ends indicate the amount
of taper present. Record all readings taken.
Refer to Engine Specifications. Plastigage generally is accompanied by two scales. One scale is in
inches, the other is a metric scale. (6) Plastigage is available in a variety of clearance
ranges. The 0.025-0.076mm (.001-.003 inch) is usually
the most appropriate for checking engine bearing
proper specifications.
LASH ADJUSTER (TAPPET) NOISE DIAGNOSIS
A tappet-like noise may be produced from several
items. Check the following items. (1) Engine oil level too high or too low. This may
cause aerated oil to enter the adjusters and cause them
to be spongy. (2) Insufficient running time after rebuilding cylin-
der head. Low speed running up to 1 hour may be
required. During this time, turn engine off and let set for a few
minutes before restarting. Repeat this several times
after engine has reached normal operating tempera-
ture. (3) Low oil pressure.
(4) The oil restrictor pressed into the vertical oil
passage to the cylinder head of Balance Shaft Engines
Only is plugged with debris. (5) Air ingested into oil due to broken or cracked oil
pump pick up. (6) Worn valve guides.
(7) Rocker arm ears contacting valve spring retainer
(2.2/2.5L engines). (8) Rocker arm loose, adjuster or tappet stuck or at
maximum extension and still leaves lash in the system. (9) Faulty lash adjuster or tappet.(a) Check for sponginess while still installed in
engine. Depress part of rocker arm just over adjuster
or pushrod . Normal adjusters should feel very firm.
Spongy adjusters can be depressed to the bottomed
position easily. (b) Remove suspected lash adjuster or tappet, pry
off retainer cap or snap ring and disassemble. Do
not reuse retainer caps . Do not interchange parts
and make sure that care and cleanliness is exercised
in the handling of parts. (c) Clean out dirt and varnish with solvent.
(d) Reassemble with engine oil.
(e) Check for sponginess.
(f) If still spongy, replace with new adjuster.
REPAIR OF DAMAGED OR WORN THREADS
Damaged or worn threads (including aluminum head
spark plug threads) can be repaired. Essentially, this
repair consists of drilling out worn or damaged
threads, tapping the hole with a special Heli-Coil (or
equivalent) Tap, and installing an insert into the
tapped hole. This brings the hole back to its original
thread size.
9 - 4 ENGINE Ä