Isuzu Rodeo UE. Manual - part 172

6E1–59

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

ELECTRONIC IGNITION SYSTEM

DIAGNOSIS

If the engine cranks but will not run or immediately stalls,
the Engine Cranks But Will Not Start chart must be used
to determine if the failure is in the ignition system or the
fuel system. If DTC P0300, P0341, P0342, or P0336 is
set, the appropriate diagnostic trouble code chart must be
used for diagnosis.
If a misfire is being experienced with no DTC set, for
diagnosis, refer to the Symptoms section.

EVAP CANISTER PURGE SOLENOID

A continuous purge condition with no purge commanded
by the PCM will set a DTC P1441. A fault (small leak) in
the EVAP purge vacuum system will set a DTC P0442.
Refer to the DTC charts for further information.

VISUAL CHECK OF THE

EVAPORATIVE EMISSION CANISTER

014RX001

If the canister is cracked or damaged, replace the
canister.

If fuel is leaking from the canister, replace the canister
and check hoses and hose routing.

IDLE AIR CONTROL (IAC) VALVE

0006

The Tech 2 displays the IAC pintle position in counts. A
count of ”0” indicates the PCM is commanding the IAC
pintle to be driven all the way into a fully–seated position.
This is usually caused by a vacuum leak.
The higher the number of counts, the more air is being
commanded to bypass the throttle blade. In order to
diagnose the IAC system, refer to IAC System Check.
For other possible causes of idle problems, refer to
Rough, Unstable, or Incorrect Idle, Stalling in Symptoms.

FUEL SYSTEM PRESSURE TEST

A fuel system pressure test is part of several of the
diagnostic charts and symptom checks. To perform this
test, refer to Fuel System Diagnosis.

FUEL METERING SYSTEM CHECK

Some failures of the fuel metering system will result in an
”Engine Cranks But Will Not Run” symptom. If this
condition exists, refer to the Cranks But Will Not Run
chart. This chart will determine if the problem is caused by
the ignition system, the PCM, or the fuel pump electrical
circuit.
For the fuel system wiring schematic, refer to Fuel
System Electrical Test.
If there is a fuel delivery problem, to diagnose the fuel
injectors, the fuel pressure regulator, and the fuel
pump,refer to Fuel System Diagnosis.
If a malfunction occurs in the fuel metering system, it
usually results in either a rich HO2S signal or a lean HO2S
signal. This condition is indicated by the HO2S voltage,
which causes the PCM to change the fuel calculation (fuel
injector pulse width) based on the HO2S reading.
Changes made to the fuel calculation will be indicated by
a change in the long term fuel trim values which can be

6E1–60

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

monitored with a Tech 2. Ideal long term fuel trim values
are around 0%; for a lean HO2S signal, the PCM will add
fuel, resulting in a fuel trim value above 0%. Some
variations in fuel trim values are normal because all
engines are not exactly the same. If the evaporative
emission canister purge is ON, the long term fuel trim may
be as low as –38%. If the long term fuel trim values are
greater than +23%, for items which can cause a lean
HO2S signal, refer to DTC P0131, DTC P0171, and DTC
1171.

FUEL INJECTOR COIL TEST

PROCEDURE AND FUEL INJECTOR

BALANCE TEST PROCEDURE

T32003

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart:
2. Relieve the fuel pressure by connecting the J

34730–1 Fuel Pressure Gauge to the fuel pressure
connection on the fuel rail.

CAUTION: In order to reduce the risk of fire and
personal injury, wrap a shop towel around the fuel
pressure connection. The towel will absorb any fuel
leakage that occurs during the connection of the fuel
pressure gauge. Place the towel in an approved
container when the connection of the fuel pressure
gauge is complete.

Place the fuel pressure gauge bleed hose in an
approved gasoline container.
With the ignition switch OFF open the valve on the
fuel pressure gauge.

3.Record the lowest voltage displayed by the DVM

after the first second of the test. (During the first
second, voltage displayed by the DVM may be
inaccurate due to the initial current surge.)

Injector Specifications:

Resistance Ohms

Voltage Specification at

C–35

C (50

F–95

11.8 – 12.6

5.7 – 6.6

The voltage displayed by the DVM should be within
the specified range.

The voltage displayed by the DVM may increase
throughout the test as the fuel injector windings
warm and the resistance of the fuel injector windings
changes.

An erratic voltage reading (large fluctuations in
voltage that do not stabilize) indicates an
intermittent connection within the fuel injector.

5. Injector Specifications:

Highest Acceptable Voltage

Reading Above/Below

C/10

C (95

F/50

Acceptable

Subtracted Value

9.5 Volts

0.6 Volt

7. The Fuel Injector Balance Test portion of this chart

(Step 7 through Step 11) checks the mechanical
(fuel delivery) portion of the fuel injector. An engine
cool–down period of 10 minutes is necessary in
order to avoid irregular fuel pressure readings due
to ”Hot Soak” fuel boiling.

6E1–61

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

Injector Coil Test Procedure (Steps 1–6) And Injector Balance Test Procedure

(Steps 7–11)

R262001

CYLINDER

1st Reading

296 kPa

(43psi)

296 kPa

(43psi)

296 kPa

(43psi)

296 kPa

(43psi)

2nd Reading

131 kPa

(19 psi)

117 kPa

(17 psi)

124 kPa

(18 psi)

145 kPa

(21 psi)

Amount of Drop (1st Reading–2nd
Reading

165 kPa

(24 psi)

179 kPa

(26 psi)

172 kPa

(25 psi)

151 kPa

(22 psi)

Av. drop = 166 kPa/24 psi +/–10
kPa/1.5 psi = 156 – 176 kPa or 22.5
– 25.5 psi

Faulty, Rich
(Too Much Fuel
Drop)

Faulty, Lean
(Too Little Fuel
Drop)

NOTE: These figures are examples only.

6E1–62

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

Injector Coil Test Procedure (Steps 1–6) And Injector Balance Test Procedure

(Steps 7–11)

Step

Action

Value(s)

Yes

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

—

Go to

Step 2

Go to

OBD

System

Check

1. Turn the engine OFF.

NOTE: In order to prevent flooding of a single cylinder
and possible engine damage, relieve the fuel pressure
before performing the fuel injector coil test procedure.

2. Relieve the fuel pressure. Refer to Test Description

Number 2.

3. Connect the J 39021–5V Fuel Injector Tester to B+

and ground, and to the J39021–90 Injector Switch
Box.

4. Connect the injector switch box to the grey fuel

injector harness connector located at the front of the
EVAP canister bracket.

5. Set the amperage supply selector switch on the fuel

injector tester to the ”Coil Test” 0.5 amp position.

6. Connect the leads from the J 39200 Digital

Voltmeter (DVM) to the fuel injector tester. Refer to
the illustrations associated with the test description.

7. Set the DVM to the tenths scale (0.0).
8. Observe the engine coolant temperature.

Is the engine coolant temperature within the specified
values?

C (50

to 35

(95

Go to

Step 3

Go to

Step 5

1. Set the injector switch box to injector #1.
2. Press the ”Push to Start Test” button on the fuel

injector tester.

3. Observe the voltage reading on the DVM.

IMPORTANT: The voltage reading may rise during the
test.

4. Record the lowest voltage observed after the first

second of the test.

5. Set the injector switch box to the next injector and

repeat steps 2, 3, and 4.

Did any fuel injector have an erratic voltage reading
(large fluctuations in voltage that did not stabilize) or a
voltage reading outside of the specified values?

5.7–6.6 V

Go to

Step 4

Go to

Step 7

Replace the faulty fuel injector(s). Refer to Fuel
Injector.

Is the action complete?

—

Go to

Step 7

—

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