Daewoo Nubira. Manual - part 119

 

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Daewoo Nubira. Manual - part 119

 

 

1F – 360

I

ENGINE CONTROLS

DAEWOO V–121 BL4

Step

No

Yes

Value(s)

Action

10

1.  Check the fuel injector driver circuit.
2.  Disconnect all of the fuel injector harness con-

nectors at the fuel injectors.

3.  Connect an injector test light between the har-

ness terminals of each fuel injector connector.

4.  Note the test light while cranking the engine.

Does the test light blink at all connectors?

Go toStep 13

Go toStep 11

11

Check the fuel injector driver wiring harness, the
connectors, and the connector terminals for the
proper connections.
Is the problem found?

Go toStep 12

Go toStep 30

12

Repair the wiring harness, the connector, or the con-
nector terminal as needed.
Is the repair complete?

System OK

13

Measure the resistance of each fuel injector at 68

³

F

(20

³

C). The resistance will increase slightly at high-

er temperatures.
Is the fuel injector resistance within the value speci-
fied?

11.6–12.4 

Ω

Go toStep 15

Go toStep 14

14

Replace any fuel injector with a resistance that is out
of specifications.
Is the repair complete?

System OK

15

Perform an injector balance test.
Is the problem found?

Go toStep 16

Go toStep 17

16

Replace any restricted or leaking fuel injectors as
needed.
Is the repair complete?

System OK

17

1.  Check for the proper ignition voltage output for

each cylinder with a spark tester.

2.  Inspect the spark plugs for cracks, wear, im-

proper gap, burned electrodes, or heavy de-
posits.

3.  Inspect the ignition wires for short conditions.
4.  Inspect all of the ignition grounds for loose con-

nections.

5.  Inspect the powertrain control module

(PCM)/engine control module (ECM) for the
proper operation.

Is the problem found?

Go toStep 18

Go toStep 19

18

Correct or replace any faulty ignition components.
Is the repair complete?

System OK

19

Does the engine misfire or cut out under load or at
idle?

Go to”Ignition

System Check”

Go toStep 20

20

Does the engine start, but then immediately stall?

Go toStep 21

Go toStep 23

21

1.  Remove the Crankshaft Position (CKP) sensor.
2.  Inspect for faulty connections and repair as

needed.

Is the problem found?

Go toStep 22

Go toStep 25

22

Repair the faulty connections as needed.
Is the repair complete?

System OK

ENGINE CONTROLS  1F – 361

DAEWOO V–121 BL4

Step

No

Yes

Value(s)

Action

23

1.  Check for the proper valve timing.
2.  Check the cylinder compression.
3.  Inspect the pushrods, the rocker arms, the

valve springs, and the camshaft lobes for ex-
cessive wear.

4.  Inspect the intake manifold and the exhaust

manifold passages for casting flash.

Is the problem found?

Go toStep 24

Go toStep 25

24

Repair or replace any components as needed.
Is the repair complete?

System OK

25

Check the Idle Air Control (IAC) valve operation. Re-
pair or replace components as needed.
Is the repair complete?

System OK

26

Check the base idle setting of the throttle body.
Is the repair complete?

Go toStep 27

Go toStep 28

27

Check the Throttle Position (TP) sensor circuit for
proper operation. Repair or replace components as
needed.
Is the repair complete?

System OK

28

Adjust the base idle setting to specifications.
Is the repair complete?

System OK

29

Repair the fuel system as needed.
Is the repair complete?

System OK

30

Replace the PCM/ECM.
Is the repair complete?

System OK

 

SURGES OR CHUGGLES

Engine power varies under steady throttle or cruise,
making it feel as if the vehicle speeds up and slows
down with no change in the accelerator pedal
position.

Important : Make sure the driver understands Torque
Converter Clutch (TCC) and A/C compressor operation as
described in the owner’s manual

The speedometer reading and the speed reading on the
scan tool should be equal.

Before diagnosing the symptom, check service bulletins
for updates.

Step

Action

Value(s)

Yes

No

1

Were the Important Preliminary Checks performed?

Go toStep 2

Go to”Impor-

tant Preliminary

Checks”

2

Connect the scan tool to the Data Link Connector
(DLC).
Does the Oxygen Sensor (O2S) respond quickly to
different throttle positions?

Go toStep 4

Go toStep 3

3

1.  Check the O2S sensor for silicone or other

contaminants from fuel or use of improper
Room Temperature Vulcanizing (RTV) sealant.

2.  Replace the contaminated O2S sensor.

Is the repair complete?

System OK

1F – 362

I

ENGINE CONTROLS

DAEWOO V–121 BL4

Step

No

Yes

Value(s)

Action

4

1.  Drive the vehicle at the speed of the complaint.
2.  Monitor the long term fuel trim reading using

the scan tool.

Is the long term fuel trim reading within the value
specified?

115–150

counts

Go toStep 7

Go toStep 5

5

Is the long term fuel trim reading below the value
specified?

115 counts

Go to”Diagnos-

tic Aids for

DTC P0172”

Go toStep 6

6

Is the long term fuel trim reading above the value
specified?

150 counts

Go to”Diagnos-

tic Aids for

DTC P0171”

7

Check the fuel system pressure while the condition
exists.
Is the fuel system pressure within specifications?

41–47 psi

(284–325 kPa)

Go toStep 8

Go toStep 17

8

Check the in–line fuel filter.
Is the filter dirty or plugged?

Go toStep 18

Go toStep 9

9

Perform an injector diagnosis.
Does the injector balance test pinpoint the problem?

Go toStep 19

Go toStep 10

10

1.  Check for proper ignition voltage output using a

spark tester.

2.  Inspect the spark plugs for cracks, wear, im-

proper gap, burned electrodes, or heavy de-
posits.

Is the problem found?

Go toStep 11

Go toStep 12

11

Repair or replace any ignition system components
as needed.
Is the repair complete?

System OK

12

1.  Inspect the powertrain control module

(PCM)/engine control module (ECM) grounds
to make sure they are clean, tight, and in their
proper locations.

2.  Inspect the vacuum lines for kinks or leaks.

Is the problem found?

Go toStep 13

Go toStep 14

13

Repair the electrical connections or the vacuum
lines as needed.
Is the repair complete?

System OK

14

Check the generator output voltage.
Is the generator voltage within the value specified?

12–16 v

Go toStep 16

Go toStep 15

15

Repair the generator.
Is the repair complete?

System OK

16

1.  Check for intermittent Exhaust Gas Recircula-

tion (EGR) valve operation.

2.  Check Torque Converter Clutch (TCC) opera-

tion.

3.  Repair or replace any components as needed.

Is the repair complete?

System OK

17

Repair the fuel system as needed.
Is the repair complete?

System OK

ENGINE CONTROLS  1F – 363

DAEWOO V–121 BL4

Step

No

Yes

Value(s)

Action

18

Replace the fuel filter.
Is the repair complete?

System OK

19

Replace the leaking or restricted fuel injectors.
Is the repair complete?

System OK

 

 

 

 

 

 

 

 

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