fuel DAEWOO LACETTI 2004 Service Manual PDF

1F – 50IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
35While cranking the engine, measure the voltage at
the EI system ignition coil connector terminal 3 .
Does the voltage fluctuate within the values speci-
fied?0.2–2.0 vGo to Step 39Go to Step 37
36Check for an open in the wire from the EI system
ignition coil connector terminal 1 to the ECM connec-
tor terminal M51.
Is the problem found?–Go to Step 38Go to Step 40
37Check for an open in the wire from the EI system
ignition coil connector terminal 3 to the ECM connec-
tor terminal M1.
Is the problem found?–Go to Step 38Go to Step 40
381. Repair the wiring as needed.
2. Connect the EI system ignition coil connector.
3. Check for the presence of spark from all of the
ignition wires.
Is spark present from all of the ignition wires?–Go to Step 3Go to Step 39
39Replace the EI system ignition coil.
Is the repair complete?–Go to Step 3–
401. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?–Go to Step 3–
411. Turn the ignition OFF.
2. Connect a fuel pressure gauge.
3. Crank the engine.
Is any fuel pressure present?–Go to Step 44Go to Step 42
421. Turn the ignition OFF.
2. Disconnect the electrical connector at the fuel
pump.
3. Connect a test light between the fuel pump
connector terminals 3 and 2.
4. Turn the ignition ON.
5. With the ignition ON, the test light should light
for the time specified.
Is the test light on?2 secGo to Step 43Go to Step 53
43Replace the fuel pump.
Is the repair complete?–Go to Step 3–
44Is the fuel pressure within the value specified?283–324 kPa
(41–47 psi)Go to Step 48Go to Step 45
451. Check the fuel filter for a restriction.
2. Inspect the fuel lines for kinks and restrictions.
Is the problem found?–Go to Step 46Go to Step 47
461. Disconnect the vacuum line from the fuel pres-
sure regulator.
2. Inspect the vacuum line for the presence of
fuel.
3. Inspect the fuel pressure regulator vacuum port
for the presence of fuel.
Is any fuel present?283–324 kPa
(41–47 psi)Go to Step 3Go to Step 47

ENGINE CONTROLS 1F – 51
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
471. Disconnect the vacuum line from the fuel pres-
sure regulator.
2. Inspect the vacuum line for the presence of
fuel.
3. Inspect the fuel pressure regulator vacuum port
for the presence of fuel.
Is any fuel presen–Go to Step 50Go to Step 51
48Check the fuel for contamination.
Is the fuel contaminated?–Go to Step 49Go to Step 65
491. Remove the contaminated fuel from the fuel
tank.
2. Clean the fuel tank as needed.
Is the repair complete?–Go to Step 3–
50Replace the fuel pressure regulator.
Is the repair complete?–Go to Step 3–
511. Remove the fuel pump assembly from the fuel
tank.
2. Inspect the fuel pump sender and the fuel cou-
pling hoses for a restriction.
3. Inspect the in–tank fuel filter for a restriction.
Is the problem found?–Go to Step 52Go to Step 43
52Replace the fuel pump sender, the in–tank fuel filter,
and/or the fuel coupling hoses as needed.
Is the repair complete?–Go to Step 3–
531. Turn the ignition OFF.
2. Disconnect the electrical connector at the fuel
pump.
3. Connect a test light between the fuel pump
connector terminal 3 and a known good
ground.
4. Turn the ignition ON.
5. With the ignition ON, the test light should light
for the time specified.
Is the test light on?2 secGo to Step 54Go to Step 55
54Repair the open wire between the fuel pump connec-
tor terminal 2 and ground.
Is the repair complete–Go to Step 3–
551. Turn the ignition OFF.
2. Disconnect the fuel pump relay.
3. Connect a test light between the fuel pump
relay connector terminal 85 and ground.
4. Turn the ignition ON.
Is the test light on?2 secGo to Step 56Go to Step 62
561. Turn the ignition OFF.
2. Connect a test light between the fuel pump
relay connector terminal 86 and battery posi-
tive.
3. Turn the ignition ON.
4. With the ignition ON, the test light should light
for the time specified.
Is the test light on?–Go to Step 57Go to Step 61

1F – 52IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
571. Turn the ignition OFF.
2. Connect a test light between the fuel pump
relay connector terminal 30 and ground.
Is the test light on?–Go to Step 58Go toStep 63
581. Turn the ignition OFF.
2. Check the wire between the fuel pump relay
connector terminal 87 and the fuel pump con-
nector terminal 3 for an open or short to
ground.
Is the repair complete?–Go to Step 2–
59Replace the fuel pump relay.
Is the repair complete?–Go to Step 3–
601. Check for an open in the wiring between the
fuel pump relay connector terminal 86 and
ground.
Is the problem found?–Go to Step 71–
61Check the wire between the fuel pump relay connec-
tor terminal 85 to the ECM connector terminal K54
for an open.
Is the problem found?–Go to Step 62Go to Step 40
62Repair the wire between the fuel pump relay connec-
tor terminal 85 to the ECM connector terminal K54.
Is the repair complete?–Go to Step 3–
63Repair the wire between the fuel pump relay connec-
tor terminal 30 and the fuse Ef18.
Is the repair complete?–Go to Step 3–
641. Turn the ignition OFF.
2. Disconnect the fuel injector harness connectors
from all of the fuel injectors.
3. Turn the ignition ON.
4. Connect a test light between the fuel injector
harness connector 2 and ground.
5. Repeat step 4 for each of the remaining fuel
injectors.
Is the test light on at all of the fuel injectors?–Go to Step 65Go to Step 68
651. Turn the ignition OFF.
2. Connect a test light between the fuel injector
harness connector terminal 1 and battery posi-
tive.
3. Crank the engine.
4. Repeat steps two and three for each of the re-
maining fuel injectors.
Does the test light flash for all of the fuel injectors?–Go to Step 66Go to Step 69
66Measure the resistance of each fuel injector.
Is the resistance within the value specified (the re-
sistance will increase slightly at higher tempera-
tures)?11.6–12.4 WSystem OKGo to Step 67
67Replace any of the fuel injectors with a resistance
out of specification.
Is the repair complete?–Go to Step 3–

ENGINE CONTROLS 1F – 53
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
68Repair the open wire(s) between the fuel injector
harness connector(s) terminal 2 and the engine har-
ness C103 terminal 10.
Is the repair complete?–Go to Step 3–
691. Check for an open between the #1 fuel injector
harness connector terminal 1 and the connec-
tor terminal M25.
2. Check for an open between the #2 fuel injector
harness connector terminal 1 and the connec-
tor terminal M22.
3. Check for an open between the #3 fuel injector
harness connector terminal 1 and the connec-
tor terminal M24.
4. Check for an open between the #4 fuel injector
harness connector terminal 1 and the connec-
tor terminal M11.
Is the problem found?–Go to Step 70Go to Step 72
70Repair the open fuel injector harness wire(s).
Is the repair complete?–Go to Step 3–
71Replace the fuse or repair the wiring as needed.
Is the repair complete?–Go to Step 3–
721. Inspect the I/P fuse F2.
2. Check for an open between the circuits from
terminal 2 for each of the four fuel injectors and
the ignition switch.
Is the problem found?–Go to Step 71–

1F – 62IENGINE CONTROLS
DAEWOO V–121 BL4
FUEL SYSTEM DIAGNOSIS
Circuit Description
The fuel pump is an in–tank type mounted to a fuel sender
assembly. The fuel pump will remain on as long as the en-
gine is cranking or running and the Engine Control Module
(ECM) is receiving reference pulses from the crankshaft
position (CKP) sensor. If there are no reference pulses,
the ECM will turn off the fuel pump two seconds after the
ignition switch is turned ON or two seconds after the en-
gine stops running. The fuel pump delivers fuel to the fuel
rail and the fuel injectors, where the fuel system pressure
is controlled from 284 to 325 kPa (41 to 47 psi) by the fuel
pressure regulator. The excess fuel is returned to the fuel
tank.
Test Description
The number(s) below refer to step(s) on the diagnostic
table.
2. When the engine is idling, the intake manifold vacu-
um is high. This vacuum is applied to the fuel pres-
sure regulator diaphragm, offsetting the spring
pressure inside the fuel pressure regulator and low-
ering the fuel pressure.10. If there is fuel bleeding back through the fuel return
outlet, this is due to a faulty fuel pressure regulator.
14. Another symptom often present when the fuel injec-
tors are leaking is hard starting. Leaking fuel injec-
tors can cause a flooding condition.
23. Fuel leaking from the fuel pump inlet is due to a
faulty one–way check valve in the fuel pump.
CAUTION : The fuel system is under pressure. To
avoid fuel spillage and the risk of personal injury or
fire, it is necessary to relieve the fuel system pressure
before disconnecting the fuel lines.
CAUTION : Do not pinch or restrict nylon fuel lines to
avoid damage that could cause a fuel leak, resulting
in possible fire or personal injury.
Fuel Pressure Relief Procedure
1. Remove the fuel cap.
2. Remove the fuel pump fuse EF18 from the engine
fuse box.
3. Start the engine and allow the engine to stall.
4. Crank the engine for an additional 10 seconds.
Fuel System Diagnosis
StepActionValue(s)YesNo
11. Relieve the fuel system pressure.
2. Install a fuel pressure gauge.
3. Turn the ignition ON.
Is the fuel pressure within the values specified and
holding steady?284~325 kPa
(41~47psi)Go to Step 2Go to Step 4
21. Allow the engine to idle.
2. Disconnect the vacuum hose from the fuel
pressure regulator.
3. Connect a vacuum pump with a gauge to the
fuel pressure regulator vacuum port.
4. Apply 41~47 kPa (12~14 in. Hg) of vacuum to
the fuel pressure regulator.
Does the fuel pressure decrease?–Go to Step 3Go to Step 15
31. Locate and correct the cause of the vacuum
restriction to the fuel pressure regulator.
2. Confirm the operation of the fuel pressure reg-
ulator.
Is the repair complete?–System OK–
41. Relieve the fuel system pressure.
2. Install a fuel pressure gauge.
3. Turn the ignition ON.
Is the fuel pressure within the values specified but
not holding steady?284~325 kPa
(41~47psi)Go to Step 5Go to Step 16
5Inspect the fuel lines for a leak.
Is the problem found?–Go to Step 6Go to Step 7

ENGINE CONTROLS 1F – 63
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
61. Replace the fuel line(s) as needed.
2. Install a fuel pressure gauge.
3. Turn the ignition ON.
Is the fuel pressure within the values specified but
not holding steady?284~325 kPa
(41~47psi)System OK–
71. 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 8Go to Step 9
81. 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 within the values specified but
not holding steady?41–47 psi
(284–325 kPa)System OK–
9With the fuel system under pressure, inspect the fuel
return outlet for leaking.
Is the problem found?–Go to Step 10Go to Step 11
101. Replace the fuel pressure regulator.
2. Install a fuel pressure gauge.
3. Turn the ignition ON.
Is the fuel pressure within the values specified but
not holding steady?284~325 kPa
(41~47psi)System OK–
11With the fuel system under pressure, inspect the fuel
inlet for leaking.
Is the problem found?–Go to Step 12Go to Step 13
121. Replace the fuel pump assembly.
2. Install a fuel pressure gauge.
3. Turn the ignition ON.
Is the fuel pressure within the values specified but
not holding steady?284~325 kPa
(41~47psi)System OK–
131. Remove the fuel rail and the fuel injectors as
an assembly.
2. With the fuel system under pressure, inspect
all of the fuel injectors for leaking.
Is the problem found?–Go to Step 14–
141. Replace the leaking fuel injector(s).
2. Install a fuel pressure gauge.
3. Turn the ignition ON.
Is the fuel pressure within the values specified but
not holding steady?284~325 kPa
(41~47psi)System OK–
151. Replace the fuel pressure regulator.
2. Disconnect the fuel pressure regulator vacuum
hose.
3. Start the engine.
4. Allow the engine to idle.
5. Connect the fuel pressure regulator vacuum
hose.
Does the fuel pressure decrease?–System OK–

1F – 64IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
161. Relieve the fuel system pressure.
2. Install a fuel pressure gauge.
3. Turn the ignition ON.
Is the fuel system pressure below the values speci-
fied and holding steady?284~325 kPa
(41~47psi)Go to Step 12Go to Step 17
171. Relieve the fuel system pressure.
2. Install a fuel pressure gauge.
3. Turn the ignition ON.
Is the fuel system pressure below the values speci-
fied and holding steady?284~325 kPa
(41~47psi)Go to Step 17–
18Inspect the fuel lines for leaks.
Is the problem found?–Go to Step 6Go to Step 19
191. 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 8Go to Step 20
201. Remove the fuel pump assembly.
2. With the fuel system under pressure, inspect
the fuel return outlet for leaking.
Is the problem found?–Go to Step 10Go to Step 21
211. Remove the fuel pump assembly.
2. With the fuel system under pressure, inspect
the fuel inlet for leaking.
Is the problem found?–Go to Step 12Go to Step 22
221. Remove the fuel rail and the fuel injectors as
an assembly.
2. With the fuel system under pressure, inspect
all of the fuel injectors for leaking.
Is the problem found?–Go to Step 14Go to Step 12

ENGINE CONTROLS 1F – 65
DAEWOO V–121 BL4
FUEL PUMP RELAY CIRCUIT CHECK (1.4L/1.6L DOHC)
Circuit Description
When the ignition switch is turned ON, the Engine Control
Module (ECM) will supply battery voltage to activate the
fuel pump relay and run the in–tank fuel pump. The fuel
pump will operate as long as the engine is cranking or run-
ning and the ECM is receiving ignition reference pulses.
If there are no reference pulses, the ECM will shut off the
fuel pump within 2 seconds after the ignition switch is
turned ON.
Diagnostic Aids
An intermittent problem may be caused by a poor connec-
tion, rubbed through wire insulation, or a broken wire in-
side the insulation.Test Description
The number(s) below refer to step(s) on the diagnostic
table.
3. This step checks for the ECM providing a ground
for the operation of the fuel pump relay.
7. By confirming that the wiring is OK using Steps 2
through 6, it can be determined that the fuel pump
relay is at fault.
9. After determining that there is no ground being pro-
vided by the ECM to the fuel pump relay, the fault is
either the ECM or the wiring between the ECM and
the fuel pump relay.

1F – 66IENGINE CONTROLS
DAEWOO V–121 BL4
Fuel Pump Relay Circuit Check (1.4L/1.6L DOHC)
StepActionValue(s)YesNo
11. Turn the ignition OFF for 10 seconds.
2. Turn the ignition ON.
3. Listen for in–tank fuel pump operation.
Does the fuel pump operate for the time specified?2 secSystem OKGo to Step 2
21. Turn the ignition OFF.
2. Disconnect the fuel pump relay.
3. Connect a test light between the fuel pump
relay connector terminal 30 and ground.
Turn the ignition ON. Is the test light on?–Go to Step 3Go to Step 8
31. Turn the ignition OFF.
2. Connect a test light between the fuel pump
relay connector terminal 86 and battery posi-
tive.
3. Turn the ignition ON.
4. With the ignition ON, the test light should light
for the time specified.
Is the test light on?2 secGo to Step 4Go to Step 9
41. Turn the ignition OFF.
2. Connect a test light between the fuel pump
relay connector terminal 30 and ground.
Is the test light on?–Go to Step 5Go to Step 11
5Check for an open or short to ground in the wire be-
tween the fuel pump relay connector terminal 87 and
the fuel pump connector terminal 3.
Is the problem found?–Go to Step 6Go to Step 7
61. Repair the wire between the fuel pump relay
connector terminal 87 and the fuel pump con-
nector terminal 3.
2. Install the fuel pump relay.
3. Turn the ignition OFF for 10 seconds.
4. Turn the ignition ON.
Does the fuel pump operate for the time specified?2 secSystem OK–
71. Replace the fuel pump relay.
2. Turn the ignition OFF for 10 seconds.
3. Turn the ignition ON.
Does the fuel pump operate for the time specified?2 secSystem OK–
8Check for an open wire between the fuel pump relay
connector terminal 30 and the battery.
Is the problem found?–Go to Step 13–
9Check for an open wire between the fuel pump relay
connector terminal 86 to the engine control module
(ECM) connector terminal 6.
Is the problem found.–Go to Step 10Go to Step 12
101. Repair the wire between the fuel pump relay
connector terminal 86 to the ECM connector
terminal 6.
2. Install the fuel pump relay.
3. Turn the ignition OFF for 10 seconds.
4. Turn the ignition ON.
Does the fuel pump operate for the time specified?2 secSystem OK–

ENGINE CONTROLS 1F – 67
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
111. Replace the fuse F2 or repair the wire between
the fuel pump relay connector terminal 30 and
the battery.
2. Install the fuel pump relay.
3. Turn the ignition OFF for 10 seconds.
4. Turn the ignition ON.
Does the fuel pump operate for the time specified?2 secSystem OK–
121. Turn the ignition OFF.
2. Replace the ECM.
3. Turn the ignition ON.
Does the fuel pump operate for the time specified?2 secSystem OK–
131. Replace the fuse F2 or repair the wire between
the fuel pump relay connector terminal 30 and
the ignition system
2. Install the fuel pump relay.
3. Turn the ignition OFF for 10 seconds.
4. Turn the ignition ON.
Does the fuel pump operate for the time specified?2 secSystem OK–