Daewoo Nubira. Manual - part 122

 

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Daewoo Nubira. Manual - part 122

 

 

1F – 372

I

ENGINE CONTROLS

DAEWOO V–121 BL4

Step

No

Yes

Value(s)

Action

11

1.  Road test the vehicle at the speed of the com-

plaint.

2.  Monitor the fuel trim reading using the scan

tool.

Is the fuel trim reading within the value specified?

115–150

counts

Go toStep 14

Go toStep 12

12

Is the fuel trim reading below the value specified?

115 counts

Go to”Diagnos-

tic Aids for

DTC P0172”

Go toStep 13

13

Is the fuel trim reading above the value specified?

150 counts

Go to”Diagnos-

tic Aids for

DTC P0171”

14

1.  Disconnect all of the fuel injector harness con-

nectors at the fuel injectors.

2.  Connect an injector test light between the har-

ness terminals of each fuel injector connector.

3.  Note the test light while cranking the engine.

Does the test light blink for all of the fuel injectors?

Go toStep 16

Go toStep 15

15

1.  Repair or replace the faulty injector drive circuit

harness, the connector, or the connector termi-
nals as needed.

2.  If the harness, the connectors, and the termi-

nals are OK, replace the powertrain control
module (PCM)/engine control module (ECM).

Is the repair complete?

System OK

16

Measure the resistance of each of the fuel injectors.
The resistance will increase slightly at higher tem-
peratures.
Is the resistance within the value specified?

11.6–12.4 

Ω

Go toStep 18

Go toStep 17

17

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

System OK

18

Perform an injector balance test.
Is the problem found?

Go toStep 19

Go toStep 20

19

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

System OK

20

1.  With the engine OFF, disconnect the fuel pres-

sure regulator vacuum hose.

2.  Thoroughly inspect the fuel pressure regulator

vacuum port and the fuel pressure regulator
vacuum hose for the presence of fuel.

Is the problem found?

Go toStep 21 

Go toStep 22

21

Replace the fuel pressure regulator as needed.
Is the repair complete?

System OK

ENGINE CONTROLS  1F – 373

DAEWOO V–121 BL4

Step

No

Yes

Value(s)

Action

22

1.  Check the ignition system output voltage for all

of the cylinders using a spark tester.

2.  Inspect the spark plugs for excessive wear,

insulation cracks, improper gap, or heavy de-
posits.

3.  Inspect the ignitionwires for cracking, hard-

ness, or improper connections.

4.  Replace any ignition wires with a resistance

over the value specified.

Is the problem found?

30,000 

Ω

Go toStep 23

Go toStep 24

23

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

System OK

24

1.  Inspect for vacuum leaks.
2.  Check for proper Positive Crankcase Ventila-

tion (PCV) operation.

3.  Check the Idle Air Control (IAC) valve opera-

tion.

4.  Inspect the PCM/ECM ground connections.

Is the problem found?

Go toStep 25

Go toStep 26

25

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

System OK

26

1.  Check the Exhaust Gas Recirculation (EGR)

valve for proper operation.

2.  Inspect the battery cables and the ground

straps for proper connections.

3.  Check the generator voltage output. Repair or

replace the generator if the voltage output is
not within the value specified.

Is the problem found?

12–16 v

Go toStep 27

Go toStep 28

27

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

System OK

29

1.  Inspect for broken engine mounts.
2.  Check for proper valve timing.
3.  Perform a cylinder compression test.
4.  Inspect for bent pushrods, worn rocker arms,

broken or weak valve springs, and a worn cam-
shaft.

5.  Perform repairs as needed.

Are all of the checks and needed repairs complete?

System OK

 

1F – 374

I

ENGINE CONTROLS

DAEWOO V–121 BL4

EXCESSIVE EXHAUST EMISSIONS OR ODORS

A vehicle fails an emission test. The vehicle has an excessive rotten egg smell.

Important : Excessive odors do not necessarily indicate excessive emissions.

Step

Action

Value(s)

Yes

No

1

Were the Important Preliminary Checks performed?

Go toStep 2

Go to”Impor-

tant Preliminary

Checks”

2

1.  Run the engine until it reaches operating tem-

perature.

2.  Perform an emission test.

Does the vehicle pass the emission test?

System OK

Go toStep 3

3

1.  Connect the scan tool to the Data Link Con-

nector (DLC).

2.  Road test the vehicle.
3.  Monitor the long term fuel trim memory.

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

115–150

counts

Go toStep 6

Go toStep 4

4

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

115 counts

Go to”Diagnos-

tic Aids for

DTC P0172”

Go toStep 5

5

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

150 counts

Go to”Diagnos-

tic Aids for

DTC P0171”

6

1.  Check for a properly installed fuel cap.
2.  Check the fuel system pressure.
3.  Perform an injector balance test.

Is the problem found?

Go toStep 7

Go toStep 8

7

1.  Repair or replace any fuel system components

as needed.

2.  Perform an emission test.

Does the vehicle pass the emission test?

System OK

8

1.  Check the ignition system for proper operation.
2.  Inspect the spark plugs for excessive wear,

insulation cracks, improper gap, or heavy de-
posits.

3.  Check the ignition wires for cracking, hardness,

or improper connections.

Is the problem found?

Go toStep 9

Go toStep 10

ENGINE CONTROLS  1F – 375

DAEWOO V–121 BL4

Step

No

Yes

Value(s)

Action

9

1.  Repair or replace any ignition system compo-

nents as needed.

2.  Perform an emission test.

Does the vehicle pass the emission test?

System OK

10

1.  Inspect for vacuum leaks.
2.  Inspect the catalytic converter for contamina-

tion.

3.  Inspect for carbon buildup on the throttle body

and the throttle plate and inside the engine.
Remove with a top engine cleaner.

4.  Check the Exhaust Gas Recirculation (EGR)

valve to make sure it opens.

5.  Check for proper Positive Crankcase Ventila-

tion (PCV) operation.

Are all checks and needed repairs complete?

System OK

 

DIESELING, RUN–ON

An engine continues to run after the ignition switch
is turned OFF.

Step

Action

Value(s)

Yes

No

1

Were the Important Preliminary Checks performed?

Go toStep 2

Go to”Impor-

tant Preliminary

Checks”

2

Does the engine run smoothly after the ignition
switch is turned OFF?

Go toStep 3

Go toStep 4

3

1.  Check the ignition switch and the ignition

switch adjustment.

2.  Replace the ignition switch if needed.

Is the repair complete?

System OK

4

1.  Check the evaporative emission system.
2.  Check for leaking fuel injectors.
3.  Check the Idle Air Control (IAC) valve opera-

tion.

4.  Inspect for vacuum leaks.
5.  Check for the proper base idle setting.

Are all checks and repairs complete?

System OK

 

 

 

 

 

 

 

 

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