Daewoo Matiz (2003 year). Manual - part 95

1F – 290  ENGINE CONTROLS

DETONATION/SPARK KNOCK

Step

Action

Value(s)

Yes

No

1

Were the Important Preliminary Checks performed?

–

Go to Step 2

Go to

“Important

Preliminary

Checks”

2

1. Fill the fuel tank with a known good grade of

gasoline that has the octane rating of the value
specified.

2. Reevaluate the vehicle’s performance.
Does the detonation problem still exist?

91 octane

Go to Step 3

System OK

3

1. Inspect for low engine coolant level.
2. Check for restricted airflow to the radiator or

restricted coolant flow.

3. Check for a faulty thermostat.
4. Check for an incorrect coolant solution.
Is the problem found?

–

Go to Step 4

Go to Step 5

4

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

–

System OK

–

5

1. Check the engine coolant temperature using the

scan tool.

2. Replace the Engine Coolant Temperature (ECT)

sensor if the resistance is not within specifications
as listed in the Diagnostic Aids for diagnostic
trouble code P0118.

Is the problem found?

–

Go to Step 6

Go to Step 7

6

Replace the ECT sensor or repair the circuit as
needed.
Is the repair complete?

–

System OK

–

7

1. Check the ignition system output with a spark

tester.

2. Inspect the spark plugs for the proper heat range

and gap.

3. Check for the proper operation of the ignition

controls.

Is the ignition system operating properly?

–

Go to Step 9

Go to Step 8

8

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

–

System Ok

–

9

1. Connect the scan tool to the Data Link Connector

(DLC).

2. Road test the vehicle at the speed of the

complaint.

3. Monitor the long term fuel trim reading from the

scanner data stream.

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

25%

Go to

“Diagnostic Aids

for DTC P0171”

Go to Step 10

10

Check the fuel system pressure.
Is the problem found?

380 kPa

(55 psi)

Go to Step 11

Go to Step 12

11

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

–

System OK

–

ENGINE CONTROLS  1F – 291

Detonation/Spark Knock (Cont’d)

Step

Action

Value(s)

Yes

No

12

1. Inspect for carbon buildup inside the engine.
2. Remove the carbon with a top engine cleaner.

Follow the instructions supplied with the product.

3. Check the basic engine parts such as the

camshaft, the cylinder head, the pistons, etc. for
excessive wear.

4. Replace any excessively worn parts.
Is the procedure complete?

–

Go to Step 13

–

13

1. Check the exhaust gas recirculation valve for

proper operation.

2. Check the air intake system for proper operation.
3. Check the torque converter clutch operation and

transaxle shift points.

4. Check the service bulletins for Programmable

Read Only Memory (PROM) updates.

5. Check the cylinder compression.
6. Repair or replace any faulty components.
Are all checks and repairs complete?

–

System OK

–

1F – 292  ENGINE CONTROLS

HESITATION, SAG, STUMBLE

Definition: Momentary lack of response as the accelera-
tor is pushed down. This can occur at any vehicle speed.
It is usually the most severe when first trying to make the
vehicle move, as from a stop. Hesitation, sag, or
stumble may cause the engine to stall if severe enough.

Important: Before diagnosing this condition, check ser-
vice bulletins for PROM updates.

Step

Action

Value(s)

Yes

No

1

Were the Important Preliminary Checks performed?

–

Go to Step 2

Go to

“Important

Preliminary

Checks”

2

1. Check the fuel system pressure. If the pressure is

not within the value specified, service the fuel
system as needed.

2. Inspect the Throttle Position (TP) sensor for

binding or sticking. The TP sensor voltage should
increase at a steady rate as the throttle is moved
toward Wide Open Throttle (WOT).

Is the problem found?

380 kPa

(55 psi)

Go to Step 3

Go to Step 4

3

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

–

System OK

–

4

1. Check the Manifold Absolute Pressure (MAP)

sensor response and accuracy.

2. Inspect the fuel for water contamination.
3. Check the Evaporative Emission (EVAP) Canister

Purge System for proper operation.

Is the problem found?

–

Go to Step 5

Go to Step 6

5

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

–

System OK

–

6

1. Disconnect all of the fuel injector harness

connectors.

2. Connect an injector test light between the

harness terminals of each fuel injector.

3. Note the test light while cranking the engine.
Does the test light blink on all connectors?

–

Go to Step 8

Go to Step 7

7

1. Repair or replace the faulty fuel injector drive

harness, the connector, or the connector terminal.

2. If the connections and the harnesses are good,

replace the Engine Control Module (ECM).

Is the repair complete?

–

System OK

–

8

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

11.6–12.4 

Ω

Go to Step 10

Go to Step 9

9

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

–

System OK

–

10

Perform an injector diagnosis.
Is the problem found?

–

Go to Step 11

Go to Step 12

11

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

–

System OK

–

12

Check the fuel system pressure after a cold start or
during moderate or full throttle acceleration.
Is the fuel pressure within specifications?

380 kPa

(55 psi)

Go to Step 14

Go to Step 13

ENGINE CONTROLS  1F – 293

Hesitation, Sag, Stumble (Cont’d)

Step

Action

Value(s)

Yes

No

13

Repair the restriction in the fuel system or replace
the faulty fuel pump.
Is the repair complete?

–

System OK

–

14

1. Check for faulty ignition wires.
2. Inspect for fouled spark plugs.
3. Check the ignition system output on each cylinder

with a spark tester.

Is the problem found?

–

Go to Step 15

Go to Step 16

15

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

–

System OK

–

16

1. Check the generator output voltage.
2. Repair or replace the generator if the generator

output is less than the value specified.

3. Check the Electric Exhaust Gas Recirculation

(EEGR) valve operation.

Are all checks and needed repairs complete?

–

System OK

–