Daewoo Nubira. Manual — part 96

ELECTRICAL WIRING DIAGRAMS

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5–3

c. POSITION OF CONNECTORS AND GROUNDS

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ENGINE ROOM FUSE BLOCK

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LEFT ”A” PILLAR INSIDE

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2.0 DOHC ENGINE

d. SPLICE PACK

S202 (BLUE)

SECTION : 1A

GENERAL ENGINE INFORMATION

TABLE OF CONTENTS

DIAGNOSIS

1A–1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

COMPRESSION TEST

1A–1

. . . . . . . . . . . . . . . . . . . . .

OIL PRESSURE TEST

1A–2

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OIL LEAK DIAGNOSIS

1A–3

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KNOCK DIAGNOSIS

1A–4

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NOISE DIAGNOSIS

1A–8

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GENERAL INFORMATION

1A–11

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CLEANLINESS AND CARE

1A–11

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ON–ENGINE SERVICE

1A–11

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DIAGNOSIS

COMPRESSION TEST

Important : Disconnect the Crankshaft Position Sensor
(CPS) connector to disable the fuel and the ignition sys-
tems.

Test the compression pressure for each cylinder. Low
compression pressure may be the fault of the valves or the
pistons. The following conditions should be considered
when checking the cylinder compression:

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The engine should be at normal operating tempera-
ture.

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The throttle must be wide open.

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All the spark plugs should be removed.

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The battery must be at or near full charge.

1. Place approximately three squirts of oil from a

plunger type oiler into each spark plug port.

2. Insert the engine compression gauge into each

spark plug port.

3. Crank test each cylinder with four to five compres-

sion strokes using the starter motor.

4. The lowest reading should not be less than 70% of

the highest reading. The compression gauge read-
ing should not be less than 689 kPa (100 psi) for
any of the cylinders.

5. Examine the gauge readings obtained after the four

”puffs” per cylinder are obtained from cranking the
starter motor. The readings are explained in the
following descriptions:

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Normal Condition – Compression builds up quickly
and evenly to specified compression on each cylin-
der.

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Piston Rings Faulty – Compression is low on the
first stroke and tends to build up on following
strokes, but does not reach normal. The compres-
sion pressure improves considerably with the addi-
tion of oil into the cylinder.

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Valves Faulty – Low compression pressure on the
first stroke. The compression pressure does not
tend to build up on the following strokes. The com-
pression pressure does not improve much with the
addition of oil into the cylinder.

1A – 2

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GENERAL ENGINE INFORMATION

DAEWOO V–121 BL4

OIL PRESSURE TEST

Step

Action

Value(s)

Yes

No

1

Is the oil pressure warning lamp on?

Go to Step 2

System OK

2

Check the oil level in the crankcase.
Is the oil level low?

Go to Step 3

Go to Step 4

3

Add oil so that the oil level is up to the MAX mark on
the indicator.
Is the repair complete?

Go to Step 1

4

Check the idle speed.
Is the idle speed below the value specified?

825 rpm

Go to Step 5

Go to Step 6

5

Increase the idle speed.
Is the speed increased?

Go to Step 1

6

Inspect the oil pressure switch.
Is the oil pressure switch incorrect or malfunction-
ing?

Go to Step 7

Go to Step 8

7

Install a new oil pressure switch.
Is the repair complete?

Go to Step 1

8

Inspect the oil pressure gauge.
Is the oil pressure gauge incorrect or malfunction-
ing?

Go to Step 9

Go to Step 10

9

Install a new oil pressure gauge.
Is the repair complete?

Go to Step 1

10

Inspect the engine oil.
Is the engine oil in the crankcase diluted or of the im-
proper viscosity?

Go to Step 11

Go to Step 12

11

Install new engine oil of the proper viscosity for the
expected temperatures.
Is the repair complete?

Go to Step 1

12

Inspect the oil pump.
Is the pump worn or dirty?

Go to Step 13

Go to Step 14

13

Replace the oil pump.
Is the repair complete?

Go to Step 1

14

Inspect the oil filter.
Is the oil filter plugged?

Go to Step 15

Go to Step 16

15

Install a new oil filter.
Is the repair complete?

Go to Step 1

16

Inspect the oil pickup screen.
Is the oil pickup screen loose or plugged?

Go to Step 17

Go to Step 18

17

Tighten or replace the oil pickup screen as neces-
sary.
Is the repair complete?

Go to Step 1

18

Inspect the oil pickup tube.
Are there any holes in the oil pickup tube?

Go to Step 19

Go to Step 20

19

Replace the oil pickup tube.
Is the repair complete?

Go to Step 1

GENERAL ENGINE INFORMATION 1A – 3

DAEWOO V–121 BL4

Step

No

Yes

Value(s)

Action

20

Inspect the bearing clearances.
Are the bearing clearances more than the values
specified?

Crankshaft

0.005 mm

(0.0001 in.)
Connecting

Rod

0.0019–0.070

mm

(0.0007–0.0025

in.)

Go to Step 21

Go to Step 22

21

Replace the bearing, if necessary.
Is the repair complete?

Go to Step 1

22

Inspect the oil galleries.
Are the oil galleries cracked, porous, or plugged?

Go to Step 23

Go to Step 24

23

Repair or replace the engine block.
Is the repair complete?

Go to Step 1

24

Inspect the gallery plugs.
Are any of the gallery plugs missing or installed im-
properly?

Go to Step 25

Go to Step 26

25

Install plugs or repair, as necessary.
Is the repair complete?

Go to Step 1

26

Inspect the camshaft.
Is the camshaft worn or is there evidence of poor
machining?

Go to Step 27

System OK

27

Replace the camshaft.
Is the repair complete?

Go to Step 1

OIL LEAK DIAGNOSIS

Most fluid oil leaks are easily located and repaired by visu-
ally finding the leak and replacing or repairing the neces-
sary parts. On some occasions, a fluid leak may be difficult
to locate or repair. The following procedures may help you
in locating and repairing most leaks.

Finding the Leak:

1. Identify the fluid. Determine whether it is engine

oil,automatic transmission fluid, power steering
fluid, etc.

2. Identify where the fluid is leaking from.

1) After running the vehicle at normal operating

temperature, park the vehicle over a large sheet
of paper.

2) Wait a few minutes.
3) You should be able to find the approximate loca-

tion of the leak by the drippings on the paper.

3. Visually check around the suspected component.

Check around all the gasket mating surfaces for
leaks. A mirror is useful for finding leaks in areas
that are hard to reach.

4. If the leak still cannot be found, it may be neces-

sary to clean the suspected area with a degreaser,
steam or spray solvent.

1) Thoroughly clean the area.
2) Dry the area.
3) Operate the vehicle for several miles at normal

operating temperature and varying speeds.

4) After operating the vehicle, visually check the

suspected component.

5) If you still cannot locate the leak, try using the

powder or black light and dye method.

Powder Method:

1. Clean the suspected area.
2. Apply an aerosol–type powder (such as foot pow-

der) to the suspected area.

3. Operate the vehicle under normal operating condi-

tions.

4. Visually inspect the suspected component. You

should be able to trace the leak path over the white
powder surface to the source.

Black Light and Dye Method:

A dye and light kit is available for finding leaks. Refer to the
manufacturer’s directions when using the kit.

1. Pour the specified amount of dye into the engine oil

fill tube.