SOHC ENGINE MECANICAL 1B–9
DAEWOO M-150 BL2
DIAGNOSTIC INFORMATION AND PROCEDURE
COMPRESSION PRESSURE CHECK
Tools Required
09915–64510 Compression Pressure Gauge
Check the compression pressure in the following proce-
dures:
1. Warm up the engine to the normal operating tempera-
ture (Cooling temperature : 80–90C (176–194F)).
2. Stop the engine and then remove the high tension
cable and the spark plug.
3. Disconnect the distributor optical sensor connector.
4. Install the compression pressure gauge 09915–64510
(a) in the hole of spark plug.
D12B301A
5. Disengage the clutch in Neutral (to lighten starting
load on engine upon cranking), and depress the ac-
celerator all the way to make the throttle fully open.
6. Crank the engine with the starting motor, and read the
highest pressure on the compression pressure gauge.
The difference of measured value between cylinders
is 98.06kPa (14.22 psi) and less.
On checking, make the connection perfectly airtight
between the hole of spark plug and compression pres-
sure gauge.
Unit Standard Limit
Compression
Pressure
– 400 rpm
kPa(psi)1,225.75
(177.73)
1,176.72–
1,274.78
(170.62–
184.84)
7. After checking, remove the gauge and install the re-
moved parts.
OIL PRESSURE CHECK
Tools Required
09915–77310 Oil Pressure Gauge
Prior to check oil pressure, check the followings:
Check oil level and add if required.
Replace the discolored, deteriorated or diluted oil.
Check any oil leakage and repair the defective parts.
Check the compression pressure in the following proce-
dures:
1. Remove the oil pressure switch (b) from the cylinder
block.
2. Install the oil pressure gauge 09915–77310 (c) to the
mounting place of the oil pressure switch.
D12B302A
3. Start the engine and warm up to the normal operating
temperature.
4. Raise the engine speed up to 2,000rpm and then
read oil pressure.
Item Unit Standard
Oil Pressure – 2000rpmkPa
(psi)245.15–294.18
(35.55–42.66)
5. After checking, wrap the threads of oil pressure
switch with a seal tape and tighten it to the specified
torque 12–16 Nm (106–144 lb-in).
6. Start the engine and check oil pressure switch for oil
leakage.
1E–10 ENGINE ELECTRICAL
DAEWOO M-150 BL2
DIAGNOSTIC INFORMATION AND PROCEDURE
IGNITION SYSTEM
ConditionProbable CauseCorrection
No CrankLow battery voltage.Charging the battery or Replace
the battery.
Battery cable is loose, corroded,
or damaged.Repair or Replace the battery
cable.
Faulty starter motor or starter
motor circuit is open.Repair or Replace the starter
motor/starter motor circuit.
Faulty ignition switch or fuse Ef2
is blown.Replace the ignition switch or fuse
Ef2.
Ground short.Repair the ground short.
Crank OK, But Too SlowLow battery voltage.Charging the battery or Replace
the battery.
Batter.
Battery cables is loose, corroded,
or damaged.Repair or Replace the battery
cable.
Faulty starter motor.Repair or Replace the starter
motor.
Starter Motor Does Not StopFaulty starter motor.Repair or Replace the starter
motor.
Faulty ignition switch.Replace the ignition switch.
Starter Motor Running, But Not
CrankingBroken the clutch pinion gear or
faulty starter motor.Replace the starter motor.
Broken the flywheel ring gear.Replace the flywheel.
Connected circuit is open.Repair the open circuit.
Overcharging BatteryFaulty the IC regulator.Replace the IC regulator.
Battery DischargeLoosen the generator drive belt.Adjust the belt tension or Replace
the belt.
The circuit is open or a short.Repair the open or a short circuit.
Faulty IC regulator.Replace the IC regulator.
Battery run down.Replace the battery.
Open ground circuit.Repair the open ground circuit.
Charging Indicator Lamp Fault IC regulator.Replace the IC regulator.
Does Not Work When the
Ignition Switch ONCharging indicator lamp is blown
or fuse F8 is blown.Repair or Replace the charging
indicator lamp/fuse F8.
(Engine Does Not Work)Faulty ignition switch.Replace the ignition switch.
Generator ground circuit is open
or a short.Repair the circuit.
Charging Indicator Lamp Faulty IC regulator.Replace the IC regulator.
Does Not Put Out Lights After
Starting the EngineBattery cable is corroded or
damaged.Repair or Replace the battery
cable.
Loosen the generator drive belt.Adjust the belt tension or Replace
the belt.
Faulty wiring harness.Repair the wiring harness.
ENGINE ELECTRICAL 1E–13
DAEWOO M-150 BL2
GENERATOR SYSTEM CHECK
When operating normally, the generator indicator lamp
will come on when the ignition switch is in the ON posi-
tion and go out when the engine starts. If the lamp oper-
ates abnormally or if an undercharged or overcharged
battery condition occurs, the following procedure may
be used to diagnose the charging system. Remember
that an undercharged battery is often caused by acces-
sories being left on overnight or by a defective switch
that allows a lamp, such as a trunk or glove box lamp, to
stay on.
Diagnose the generator with the following procedure:
1. Visually check the belt and wiring.
2. With the ignition switch in the ON position and the en-
gine stopped, the charge indicator lamp should be on.
If not, detach the harness at the generator and
ground the ‘‘L’’ terminal in the harness with a fused,
5-ampere jumper lead.If the lamp lights, replace the generator. Refer to
“Generator” in the On-Vehicle Service section.
If the lamp does not light, locate the open circuit
between the ignition switch and the harness con-
nector. The indicator lamp bulb may be burned out.
3. With the ignition switch in the ON position and the en-
gine running at moderate speed, the charge indicator
lamp should be off. If not, detach the wiring harness
at the generator.
If the lamp goes off, replace the generator. Refer to
“Generator” in the On-Vehicle Service section.
If the lamp stays on, check for a short to ground in
the harness between the connector and the indica-
tor lamp.
Important: Always check the generator for output be-
fore assuming that a grounded ‘‘L’’ terminal circuit has
damaged the regulator. Refer to “Generator” in the Unit
Repair section.
ENGINE ELECTRICAL 1E – 19
DAEWOO M-150 BL2
REPAIR INSTRUCTIONS
UNIT REPAIR
D102E701
STARTER MOTOR
Inspection / Measurement
(Before the Overhaul)
1. Remove the starter. Refer to “Starter” in this section.
2. Pinion clearance inspection.
Disconnect the starter motor terminal M (1).
Connect the 12-volt battery lead to the starter mo-
tor terminals M and S.
Notice: Complete the testing in a minimum amount of
time to prevent overheating and damaging the solenoid.
(in 10 seconds)
D102E702
Switch on to move the pinion gear (2).
Now check the clearance between the pinion and
the stopper with the filler gauge (3).
If the clearance does not fall within the limits,
check for improper installation and replace all worn
parts.
D102E703
3. Magnetic switch pull-in test.
Disconnect the starter motor terminal M (1).
Connect the 12-volt battery lead to the starter mo-
tor terminals M and S.
Notice: Complete the testing in a minimum amount of
time to prevent overheating and damaging the solenoid.
(in 10 seconds)
ENGINE CONTROLS 1F–7
DAEWOO M-150 BL2
manifold to decrease combustion temperature. The
amount of exhaust gas recirculated is controlled by vari-
ations in vacuum and exhaust back pressure. If too
much exhaust gas enters, combustion will not take
place. For this reason, very little exhaust gas is allowed
to pass through the valve, especially at idle.
The EEGR valve is usually open under the following
conditions:
Warm engine operation.
Above idle speed.
Results of Incorrect Operation
Too much EEGR flow tends to weaken combustion,
causing the engine to run roughly or to stop. With too
much EEGR flow at idle, cruise, or cold operation, any of
the following conditions may occur:
The engine stops after a cold start.
The engine stops at idle after deceleration.
The vehicle surges during cruise.
Rough idle.
If the EEGR valve stays open all the time, the engine
may not idle. Too little or no EEGR flow allows combus-
tion temperatures to get too high during acceleration
and load conditions. This could cause the following con-
ditions:
Spark knock (detonation)
Engine overheating
Emission test failure
INTAKE AIR TEMPERATURE
SENSOR
The Intake Air Temperature (IAT) sensor is a thermistor,
a resistor which changes value based on the tempera-
ture of the air entering the engine. Low temperature pro-
duces a high resistance (100 kohms at –40C [–40F]),
while high temperature causes a low resistance (70
ohms at 130C [266F]).
The Engine Control Module (ECM) provides 5 volts to
the IAT sensor through a resistor in the ECM and mea-
sures the change in voltage to determine the IAT. The
voltage will be high when the manifold air is cold and low
when the air is hot. The ECM knows the intake IAT by
measuring the voltage.
The IAT sensor is also used to control spark timing when
the manifold air is cold.
A failure in the IAT sensor circuit sets a diagnostic
trouble code P0112 or P0113.
IDLE AIR CONTROL VALVE
Notice: Do not attempt to remove the protective cap
and readjust the stop screw. Misadjustment may result
in damage to the Idle Air Control (IAC) valve or to the
throttle body.The IAC valve is mounted on the throttle body where it
controls the engine idle speed under the command of
the Engine Control Module (ECM). The ECM sends volt-
age pulses to the IAC valve motor windings, causing the
IAC valve pintle to move in or out a given distance (a
step or count) for each pulse. The pintle movement con-
trols the airflow around the throttle valves which, in turn,
control the engine idle speed.
The desired idle speeds for all engine operating condi-
tions are programmed into the calibration of the ECM.
These programmed engine speeds are based on the
coolant temperature, the park/neutral position switch
status, the vehicle speed, the battery voltage, and the
A/C system pressure, if equipped.
The ECM “learns” the proper IAC valve positions to
achieve warm, stabilized idle speeds (rpm) desired for
the various conditions (park/neutral or drive, A/C on or
off, if equipped). This information is stored in ECM ”keep
alive” memories (information is retained after the ignition
is turned off). All other IAC valve positioning is calcu-
lated based on these memory values. As a result, en-
gine variations due to wear and variations in the
minimum throttle valve position (within limits) do not af-
fect engine idle speeds. This system provides correct
idle control under all conditions. This also means that
disconnecting power to the ECM can result in incorrect
idle control or the necessity to partially press the accel-
erator when starting until the ECM relearns idle control.
Engine idle speed is a function of total airflow into the
engine based on the IAC valve pintle position, the
throttle valve opening, and the calibrated vacuum loss
through accessories. The minimum throttle valve posi-
tion is set at the factory with a stop screw. This setting
allows enough airflow by the throttle valve to cause the
IAC valve pintle to be positioned a calibrated number of
steps (counts) from the seat during “controlled” idle op-
eration. The minimum throttle valve position setting on
this engine should not be considered the “minimum idle
speed,” as on other fuel injected engines. The throttle
stop screw is covered with a plug at the factory following
adjustment.
If the IAC valve is suspected as being the cause of im-
proper idle speed, refer to “Idle Air Control System
Check” in this section.
MANIFOLD ABSOLUTE PRESSURE
SENSOR
The Manifold Absolute Pressure (MAP) sensor mea-
sures the changes in the intake manifold pressure which
result from engine load and speed changes and con-
verts these to a voltage output.
A closed throttle on engine coast down produces a rela-
tively low MAP output. MAP is the opposite of vacuum.
When manifold pressure is high, vacuum is low. The
MAP sensor is also used to measure barometric pres-
sure. This is performed as part of MAP sensor calcula-
1F–34 ENGINE CONTROLS
DAEWOO M-150 BL2
FUEL SYSTEM DIAGNOSIS
Circuit Description
The fuel pump is an in-tank type mounted to a fuel send-
er assembly. The fuel pump will remain on as long as the
engine is cranking or running and the Engine Control
Module (ECM) is receiving reference pulses from the
crankshaft position (CKP) sensor. If there are no refer-
ence pulses, the ECM will turn off the fuel pump two sec-
onds after the ignition switch is turned ON or two
seconds after the engine stops running. The fuel pump
delivers fuel to the fuel rail and the fuel injectors, where
the fuel system pressure is controlled from 380 kPa (55
psi) by the fuel pressure regulator. The excess fuel is re-
turned to the fuel tank.
Caution: The fuel system is under pressure. To
avoid fuel spillage and the risk of personal injury orfire, it is necessary to relieve the fuel system pres-
sure before disconnecting the fuel lines.
Caution: Do not pinch or restrict nylon fuel lines.
Damage to the lines could cause a fuel leak, result-
ing in possible fire or personal injury.
Fuel Pressure Relief Procedure
1. Remove the fuel cap.
2. Remove the fuel pump fuse EF23 from the engine
fuse block.
3. Start the engine and allow the engine to stall.
4. Crank the engine for an additional 10 seconds.
Fuel System Pressure Test
Step Action Value(s) Yes No
1
1. Relieve the fuel system pressure.
2. Install a fuel pressure gauge.
3. Turn the ignition ON.
Is the fuel pressure around the values specified and
holding steady?
380 kPa
(55 psi)
System OK
Go to Step 2
2
1. Relieve the fuel system pressure.
2. Install a fuel pressure gauge.
3. Turn the ignition ON.
Is the fuel pressure around the values specified but
not holding steady?
380 kPa
(55 psi)
Go to Step 13
Go to Step 3
3
Inspect the fuel lines for a leak.
Is the problem found?
–
Go to Step 4
Go to Step 5
4
1. Replace the fuel line(s) as needed.
2. Install a fuel pressure gauge.
3. Turn the ignition ON.
Is the fuel pressure around the values specified and
holding steady?
380 kPa
(55 psi)
System OK
–
5
1. Remove the fuel pump assembly.
2. With the fuel pump under pressure, inspect the
fuel pump coupling hoses for leaking.
Is the problem found?
–
Go to Step 6
Go to Step 7
6
1. Tighten or replace the fuel pump coupling hoses
as needed.
2. Install a fuel pressure gauge.
3. Turn the ignition ON.
Is the fuel pressure around the values specified and
holding steady?
380 kPa
(55 psi)
System OK
Go to Step 8
7
With the fuel system under pressure, inspect the fuel
return outlet for leaking.
Is the problem found?
–
Go to Step 8
Go to Step 9
1F–42 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F070
IDLE AIR CONTROL SYSTEM CHECK
Circuit Description
The Engine Control Module (ECM) controls the engine
idle speed with the Idle Air Control (IAC) valve. To in-
crease the idle speed, the ECM pulls the IAC pintle
away from its seat, allowing more air to pass by the
throttle body. To decrease the idle speed, it extends the
IAC valve pintle toward its seat, reducing bypass air
flow. A scan tool will read the ECM commands to the
IAC valve in counts. The higher counts indicate more air
bypass (higher idle). The lower counts indicate less air is
allowed to bypass (lower idle).
Diagnostic Aids
If the idle is too high, stop the engine. Fully extend the
Idle Air Control (IAC) valve with a IAC driver. Start the
engine. If the idle speed is above 950 rpm, locate and
repair the vacuum leak. Also, check for a binding throttle
plate or throttle linkage or an incorrect base idle setting.
Idle Air Control Valve Reset Procedure
Whenever the battery cable or the Engine Control Mod-
ule (ECM) connector or the ECM fuse EF6 is discon-nected or replaced, the following idle learn procedure
must be performed:
1. Turn the ignition ON for 5 seconds.
2. Turn the ignition OFF for 10 seconds.
3. Turn the ignition ON for 5 seconds.
4. Start the engine in park/neutral.
5. Allow the engine to run until the engine coolant is
above 85C (185F ).
6. Turn the A/C ON for 10 seconds, if equipped.
7. Turn the A/C OFF for 10 seconds, if equipped.
8. If the vehicle is equipped with an automatic trans-
axle, apply the parking brake. While pressing the
brake pedal, place the transaxle in D (drive).
9. Turn the A/C ON for 10 seconds, if equipped.
10. Turn the A/C OFF for 10 seconds, if equipped.
11. Turn the ignition OFF. The idle learn procedure is
complete.
1F–108 ENGINE CONTROLS
DAEWOO M-150 BL2
DTC P0171 – Fuel Trim System Too Lean (Cont’d)
StepActionValue(s)YesNo
9
1. Visually/physically inspect the following items for
vacuum leaks:
Intake manifold.
Throttle body.
Injector O-rings.
2. Repair any leaks found as necessary.
Is the repair complete?
–
Go to Step 16Go to Step 16
10
Allow the engine to idle.
Are the Idle Air Control (IAC) counts above the
specified value?
5Go to Step 11Go to Step 12
11
Check the fuel for excessive water, alcohol, or other
contaminants and correct the contaminated fuel
condition if present.
Is the repair complete?
–
Go to Step 16Go to Step 13
12
Check the IAC valve performance. Refer to “DTC
P0506 Idle Speed RPM Lower Than Desired Idle
Speed” or “DTC P0507 Idle Speed RPM Higher
Than Desired Idle Speed” in this section and repair
as necessary.
Is the repair complete?
–
Go to Step 16Go to Step 13
13
1. Connect a fuel pressure gauge to the fuel system.
2. Turn the ignition OFF for at least 10 seconds.
3. Turn the ignition ON, with the engine OFF. The
fuel pump will run for approximately 2–3 seconds.
It may be necessary to cycle the ignition switch
ON more than once to obtain maximum fuel
pressure.
4. Note the fuel pressure with the fuel pump running.
The pressure should be within the specified value.
When the fuel pump stops, the pressure may vary
slightly then hold steady.
Is the fuel pressure steady and does the fuel
pressure hold?
380 KPa
(55 psi)
Go to Step 14
Go to
“Fuel System
Diagnosis”
14
1. Start and idle the engine at normal operating
temperature.
2. The fuel pressure noted in the above step should
drop by the indicated value.
Does the fuel pressure drop by the indicated value?
21–69 KPa
(3–10 psi)
Go to
“Fuel Injector
2alance Test”Go to
“Fuel System
Diagnosis”
15Replace the MAP sensor.
Is the action complete?–Go to Step 16–
16
1. Using the scan tool, clear the Diagnostic Trouble
Codes (DTCs).
2. Start the engine and idle at normal operating
temperature.
3. Operate the vehicle within the Conditions for
setting this DTC as specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?
–
Go to Step 17Go to Step 2
17
Check if any additional DTCs are set.
Are any DTCs displayed that have not been
diagnosed?
–
Go to
applicable DTC
table
System OK