Content .. 95 96 97 98 ..

Daewoo Matiz (2003 year). Manual - part 97

1F – 298 ENGINE CONTROLS

Rough, Unstable, or Incorrect Idle, Stalling (Cont’d)

Step

Action

Value(s)

Yes

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

–20%

Go to

“Diagnostic Aids

for DTC P0172”

Go to Step 13

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

25%

Go to

“Diagnostic Aids

for DTC P0171”

–

1. Disconnect all of the fuel injector harness

connectors at the fuel injectors.

2. Connect an injector test light between the

harness 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 to Step 16

Go to Step 15

1. Repair or replace the faulty injector drive circuit

harness, the connector, or the connector
terminals as needed.

2. If the harness, the connectors, and the terminals

are OK, replace the Engine Control Module
(ECM).

Is the repair complete?

–

System OK

–

Measure the resistance of each of the fuel injectors.
Is the resistance within the value specified (the
resistance will increase slightly at higher
temperatures)?

11.6–12.4

Ω

Go to Step 18

Go to Step 17

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

–

System OK

–

Perform an injector diagnosis.
Is the problem found?

–

Go to Step 19

Go to Step 20

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

–

System OK

–

1. With the engine OFF, disconnect the fuel

pressure 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 to Step 21

Go to Step 22

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

–

System OK

–

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
deposits.

3. Inspect the ignition wires for cracking, hardness,

or improper connections.

4. Replace any ignition wires with a resistance over

the value specified.

Is the problem found?

30000

Ω

Go to Step 23

Go to Step 24

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

–

System OK

–

ENGINE CONTROLS 1F – 299

Rough, Unstable, or Incorrect Idle, Stalling (Cont’d)

Step

Action

Value(s)

Yes

1. Inspect for vacuum leaks.
2. Check for proper Positive Crankcase Ventilation

(PCV) operation.

3. Check the Idle Air Control (IAC) valve operation.
4. Inspect the ECM ground connections.
Is the problem found?

–

Go to Step 25

Go to Step 26

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

–

System OK

–

1. Check the Electric Exhaust Gas Recirculation

(EEGR) 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 to Step 27

Go to Step 28

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

–

System OK

–

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
camshaft.

5. Perform repairs as needed.
Are all of the checks and needed repairs complete?

–

System OK

–

1F – 300 ENGINE CONTROLS

EXCESSIVE EXHAUST EMISSIONS OR ODORS

Definition: A vehicle fails an emission test. The vehicle
has an excessive rotten egg smell. Excessive odors do
not necessarily indicate excessive emissions.

Step

Action

Value(s)

Yes

Were the Important Preliminary Checks performed?

–

Go to Step 2

Go to

“Important

Preliminary

Checks”

1. Run the engine until it reaches operating

temperature.

2. Perform an emission test.
Did the vehicle pass the emission test?

–

System OK

Go to Step 3

1. Connect the scan tool to the Data Link Connector

(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?

–20 – 25 %

Go to Step 6

Go to Step 4

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

–20 %

Go to

“Diagnostic Aids

for DTC P0172”

Go to Step 5

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

25 %

Go to

“Diagnostic Aids

for DTC P0171”

–

1. Check for a properly installed fuel cap.
2. Check the fuel system pressure.
3. Perform an injector diagnosis.
Is the problem found?

–

Go to Step 7

Go to Step 8

1. Repair or replace any fuel system components as

needed.

2. Perform an emission test.
Did the vehicle pass the emission test?

–

System OK

–

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

insulation cracks, improper gap, or heavy
deposits.

3. Check the ignition wires for cracking, hardness, or

improper connections.

Is the problem found?

–

Go to Step 9

Go to Step 10

1. Repair or replace any ignition system components

as needed.

2. Perform an emission test.
Did the vehicle pass the emission test?

–

System OK

–

ENGINE CONTROLS 1F – 301

Excessive Exhaust Emissions or Odors (Cont’d)

Step

Action

Value(s)

Yes

1. Inspect for vacuum leaks.
2. Inspect the catalytic converter for contamination.
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 Electric Exhaust Gas Recirculation

(EEGR) valve for not opening.

5. Check for proper Positive Crankcase Ventilation

(PCV) operation.

Are all checks and needed repairs complete?

–

System OK

–

Content .. 95 96 97 98 ..