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Isuzu Rodeo UE. Manual - part 250

6E1–371

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

BACKFIRE SYMPTOM

DEFINITION:
Fuel ignites in the intake manifold, or in the exhaust
system, making a loud popping noise.

Step

Action

Value(s)

Yes

Was the On–Board Diagnostic (OBD) System Check
performed?

—

Go to Step 2

Go to OBD

System

Check

1. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,

correct the condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

—

Verify repair

Go to Step 3

Was a visual/physical check performed?

—

Go to Step 4

Go to Visual /

Physical

Check

Check for proper ignition voltage output with spark
tester J 26792.

Was a problem found?

—

Verify repair

Go to Step 5

1. Remove the spark plugs and check for gas or oil

fouling, cracks, wear, improper gap, burned
electrodes of heavy deposits.

2. If spark plugs are fouled, the cause of fouling must

be determined before replacing the spark plugs.

Was a problem found?

—

Verify repair

Go to Step 6

1. Visually/physically inspect the secondary ignition

wires. Check for the following conditions:

Verify that all ignition wire resistances are less
than the specified value.

Verify that ignition wires are correctly routed to
eliminate cross–firing.

Verify that ignition wires are not arcing to
ground. Spraying the secondary ignition wires
with a light mist of water may help locate an
intermittent problem.

Was a problem found?

—

Verify repair

Go to Step 7

Check for an intermittent ignition system malfunction:

Intermittent CKP 58X signal.

Intermittent ignition feed circuit or sensor ground
circuit to the crankshaft position sensor.

Was a problem found?

—

Verify repair

Go to Step 8

To determine if there is a problem with fuel delivery,
refer to Fuel System Diagnosis.

Was a problem found?

—

Verify repair

Go to Step 9

1. Check for the following engine mechanical

problems:

Low compression

Leaking cylinder head gasket

Worn or incorrect camshaft

Incorrect valve timing

Sticking or leaking valves

Camshaft drive belt slipped or stripped.

Was a problem found?

—

Verify repair

Go to Step 10

6E1–372

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

Step

Yes

Value(s)

Action

Check the intake and exhaust manifold(s) for casting
flash. Refer to Engine Mechanical.

Was a problem found?

—

Verify repair

Go to Step 11

1. Review all the diagnostic procedures within this

table.

2. If all procedures have been completed and no

malfunctions have been found, review/inspect the
following:

Visual/physical inspection

Tech 2 data

Freeze Frame data/Failure Records buffer

All electrical connections within a suspected
circuit and/or system

Was a problem found?

—

Verify repair

Contact

Technical

Assistance

6E1–373

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

CUTS OUT, MISSES SYMPTOM

DEFINITION:
Steady pulsation or jerking that follows engine speed;
usually more pronounced as engine load increases.

Step

Action

Value(s)

Yes

Was the On–Board Diagnostic (OBD) System Check
performed?

—

Go to Step 2

Go to OBD

System

Check

1. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,

correct the condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

—

Verify repair

Go to Step 3

Was a visual/physical check performed?

—

Go to Step 4

Go to Visual /

Physical

Check

Check the PCM grounds to verify that they are clean
and tight. Refer to the PCM wiring diagrams in
Electrical Diagnosis.

Was a problem found?

—

Verify repair

Go to Step 5

Monitor ”Long Term Fuel Trim” on the Tech 2.

Is the ”Long Term Fuel Trim” in the negative range (rich
condition)?

—

Go to Step 6

Go to Step 7

Check items that can cause the engine to run rich.
Refer to ”Diagnostic Aids” in DTC P0172.

Was a problem found?

—

Verify repair

Go to Step 9

Is the long term fuel trim significantly in the positive
range (lean condition)?

—

Go to Step 8

Go to Step 9

Check items that can cause the engine to run lean.
Refer to Diagnostic Aids in DTC P0171.

Was a problem found?

—

Verify repair

Go to Step 9

1. Check for incorrect idle speed. Ensure that the

following conditions are present:

Engine fully warm.

Accessories are OFF.

2. Using a Tech 2, monitor the IAC position.

Is the IAC position within the specified values?

Between 5

and 50

counts

Go to Step 11

Go to Step 10

1. Visually/physically inspect for the following

conditions:

Restricted air intake system. Check for a
restricted air filter element, or foreign objects
blocking the air intake system.

Check for objects blocking the IAC passage or
throttle bore, excessive deposits in the IAC
passage and on the IAC pintle, and excessive
deposits in the throttle bore and on the throttle
plate.

Check for a condition that causes a large
vacuum leak, such as an incorrectly installed
or faulty crankcase ventilation valve or brake
booster hose disconnected.

Was a problem found?

—

Verify repair

Go to Step 11

6E1–374

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

Step

Yes

Value(s)

Action

Check the injector connections. If any of the injectors
are connected to an incorrect cylinder, correct as
necessary.

Was a problem found?

—

Verify repair

Go to Step 12

1. Perform the Injector Coil/Balance Test.

Was a problem found?

—

Verify repair

Go to Step 13

1. Check for fuel in the pressure regulator vacuum

hose.

2. If fuel is present, replace the fuel pressure regulator

assembly.

Was a problem found?

—

Verify repair

Go to Step 14

Check for proper ignition voltage output with spark
tester J 26792.

Was a problem found?

—

Verify repair

Go to Step 15

1. Remove spark plugs and check for gas or oil fouling,

cracks, wear, improper gap, burned electrodes of
heavy deposits.

2. If spark plugs are fouled, the cause of fouling must

be determined before replacing the spark plugs.

Was a problem found?

—

Verify repair

Go to Step 16

Check for a loose ignition control module ground.

Was a problem found?

—

Verify repair

Go to Step 17

Using a Tech 2, monitor the TP angle with the engine
idling.

Is the TP angle at the specified value and steady?

Go to Step 18

For further

diagnosis,

refer to DTC

P0123

Check the PCV valve for proper operation.

Was a problem found?

—

Verify repair

Go to Step 19

Check for the following engine mechanical problems:

Low compression

Leaking cylinder head gasket

Worn or incorrect camshaft

Incorrect valve timing

Sticking or leaking valves

Camshaft drive belt slipped or stripped.

Was a problem found?

—

Verify repair

Go to Step 20

Check for faulty motor mounts. Refer to Engine
Mechanical for inspection of the mounts.

Was a problem found?

—

Verify repair

Go to Step 21

1. Review all the diagnostic procedures within this

table.

2. If all procedures have been completed and no

malfunctions have been found, review/inspect the
following:

Visual/physical inspection

Tech 2 data

Freeze Frame data/Failure Records buffer

All electrical connections within a suspected
circuit and/or system

Was a problem found?

—

Verify repair

Contact

Technical

Assistance

Content .. 248 249 250 251 ..