2004 ISUZU TF SERIES fuel consumption

ELECTRICAL-BODY AND CHASSIS 8A-271
Tachometer Off-Vehicle Inspection
Remove the tachometer from the meter assembly and
measure the resistance value and the current consumption
between each terminal.


SELF DIAGNOSTIC FUNCTION
Check that the speedometer, tachometer, fuel gauge, and
temperature gauge operate properly.

821R300033

Entering the self-diagnostic mode
1. Push in and hold the “Change Indicator and Reset” knob.
2. Turn the ignition ON.
3. When the LCD odometer turns ON, release the “Change
Indicator and Reset” knob.
4. Push in and release the “Change Indicator and Reset”knob
three times in quick succession.
The meter cluster is now in “Self-diagnostic” mode.
NOTE: Steps 2-4 must be performed within 7 seconds.
The meter cluster will not enter “Self-diagnostic”mode if any of
the following conditions occur:
1. The “Change Indicator and Reset” knob is not depressed
when the ignition is turned ON.
2. The “Change Indicator and Reset” knob is released within
600ms of turning the ignition ON.
3. The “Change Indicator and Reset” knob is not depressed
and released three times within 7 seconds.

TROUBLESHOOTING 6 – 1


SECTION 6
TROUBLESHOOTING


TABLE OF CONTENTS
PAGE PAGE
BASIC INSPECTION PROCEDURE ... 6– 2

1. HARD STARTING ........................... 6– 3

1-1.Starter Motor Inoperative ......... 6– 3

1-2. Starter Motor Operates But
Engine Does Not Turn Over .......... 6– 3

1-3. Engine Turns Over But Does
Not Start Engine ............................. 6– 4

2. UNSTABLE IDLING ........................ 6– 5

3. INSUFFICIENT POWER ................. 6– 6

4. EXCESSIVE FUEL
CONSUMPTION ................................. 6– 7

5. EXCESSIVE OIL CONSUMPTION.. 6– 8

6. OVERHEATING............................... 6– 9

7. WHITE EXHAUST SMOKE ............. 6– 9

8. DARK EXHAUST SMOKE .............. 6– 10

9. OIL PRESSURE DOES NOT RISE . 6– 11

10. ABNORMAL ENGINE NOISE ....... 6– 12

10-1. Engine Knocking.................... 6– 12

10-2. Gas Leakage Noise ................ 6– 12

10-3. Continuous Noise .................. 6– 13

10-4. Slapping Noise ....................... 6– 13

10-5. Excessive Turbocharger
Noise ............................................... 6– 14
11. ROTATING PART WEAR OF
TURBOCHARGER ............................. 6– 14

12. OIL LEAKAGE FROM
TURBOCHRGER ............................... 6– 15

13. INSUFFICIENT ACCELERATION
AND/OR LACK OF POWER DUE
TO TURBOCHARGER ....................... 6– 15

14. BATTERY CHARGING AND
NOISE PROBLEM.............................. 6– 16

14-1. Battery No Charging .............. 6– 16

14-2. Battery Overcharging ............ 6– 16

14-3. Battery Under Charging......... 6– 17

14-4. Battery Unstable Charging
Current ............................................ 6– 17

14-5. Charging System Noise ......... 6– 18

15. STARTER MOTOR PROBLEM..... 6– 19

15-1. Starter Motor Pinion Engages
to Ring Gear But Engine Does
Not Turn Over ................................. 6– 19

15-2. Incorrect Pinion And Ring
Gear Engagement .......................... 6– 19

15-3. Starter Motor Continues To
Run After The Starter Switch Is
Turned Off ....................................... 6– 20

15-4. Excessive Commutator
Sparking .......................................... 6– 20

TROUBLESHOOTING 6 – 7
4. Excessive Fuel Consumption
Step Action Value(s) Yes No
1 Was the air cleaner element clogged? — Clean or
replace the air
cleaner
element. Go to Step 2
2 Was the air leakage found from the air intake side of
the turbocharger? — Repair or
replace the air
intake side of
the
turbocharger. Go to Step 3
3 Was the turbocharger working completely? —
Go to Step 4 Replace the
turbocharger
4 Was there the fuel leakage? — Repair or
replace the fuel
leakage part. Go to Step 5
5 Was the compression pressure OK? 3.0 MPa
(31.0 kg/cm2,
441 psi) at
200 rpm
Go to Step 6 Readjust the
valve clearance
or replace the
cylinder head
gasket or
cylinder liner or
piston or piston
ring or valve
and valve seat
6 Was the injection nozzle pressure or spray pattern
normal? —
Go to Step 7 Replace the
injection nozzle
7 Are any DTC stored? — Go to indicated
DTC Solved

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–407
EXCESSIVE WHITE SMOKE
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go to On Board
Diagnostic
(OBD) System
Check
2 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
3 Was a visually/physical check performed?
—Go to Step 4Go to Visual /
physical Check
4 Is the customer using the incorrect fuel type? Diesel fuel
onlyReplace with
diesel fuel Go to Step 5
5 Check the engine coolant consumption to verify that it
leaks to combustion chamber or ex haust through the
gasket.
Was a problem found?—Verify repair Go to Step 6
6 Check the ECM & PSG grounds to verify that they are
clean and tight. Refer to the ECM wiring diagrams.
Was a problem found?—Verify repair Go to Step 7
7 1. Using the Tech 2, display the ECT sensor and IAT
sensor value.
2. Check the displayed value.
Does the Tech 2 indicate correct temperature
depending on engine condition?
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 8
8 1. Using the Tech 2, display the FT sensor value.
2. Check the displayed value.
Does the Tech 2 indicate correct temperature
depending on engine condition?
If a problem is found, repair as necessary.
Was the problem found?—Go to Step 30Go to Step 9
9 1. Using the Tech 2, ignition “On” and engine “Run”.
2. Monitor the “Mass Air Flow” in the data display.
Does the Tech 2 indicate correct “Mass Air Flow”
depending on accelerator pedal operation? —Go to Step 14Go to Step 10
10 Remove the MAF & IAT sensor assembly and check
for the following conditions.
Objects blocking at the MAF sensor element.
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 11
11 Check the MAF sensor harness for the following
conditions.
Check for poor connector connection.
Check for misrouted harness.
Check for any accessory parts which may cause
electric interference.
If a problem is found, repair as necessary.
Was a problem found? —Verify repair Go to Step 12

6F – 16 EXHAUST SYSTEM
GENERAL DESCRIPTION



036LV002

The turbocharger internal mechanism consists of the turbine wheel, the compressor wheel, and the radial bearings.
These parts are supported by the bearing housing.
The turbocharger external mechanism consists of the compressor housing air intake port and the turbine housing
air exhaust port.
The turbocharger increases air intake efficiency. This results in increased engine power, reduced fuel consumption,
and minimal engine noise.
The turbocharger operates at very high speeds and temperatures. Part materials have been carefully selected and
machined to extremely high precision.
Turbocharger servicing requires great care and expertise.
If reduced performance is noted, check the engine for damage or wear. If there is no apparent engine damage or
wear, trouble with the turbocharger is indicated.

6A-18 ENGINE MECHANICAL (6VE1 3.5L)
Fuel Consumption Excessive
Symptom Possible Cause Action
Trouble in fuel system Mixture too rich or too lean due to
trouble in fuel injection system Refer to “Abnormal Combustion"
Fuel cut function does not work Refer to “Abnormal Combustion"
Trouble in ignition system Misfiring or abnormal combustion due
to trouble in ignition system Refer to “Hard Start" or “Abnormal
Combustion"
Others Engine idle speed too high Reset to Section 6E
Returning of accelerator control
sluggish Correct
Fuel system leakage Correct or replace
Clutch slipping Correct
Brake drag Correct
Selection of transmission gear
incorrect Caution operator of incorrect gear
selection
Lubrication Problems
Symptom Possible Cause Action
Oil pressure too low Wrong oil in use Replace with correct engine oil
Relief valve sticking Replace
Oil pump not operating properly Correct or replace
Oil pump strainer clogged Clean or replace strainer
Oil pump worn Replace
Oil pressure gauge defective Correct or replace
Crankshaft bearing or connecting rod
bearing worn Replace
Oil contamination Wrong oil in use Replace with correct engine oil
Oil filter clogged Replace oil filter
Cylinder head gasket damage Replace gasket
Burned gases leaking Replace piston and piston rings or
cylinder body assembly
Oil not reaching valve system Oil passage in cylinder head or
cylinder body clogged Clean or correct

ENGINE DIAGNOSIS (C24SE) 6-1
SECTION 6
ENGINE DIAGNOSIS
CONTENTS
PAGE
Engine Diagnosis............................................................................................................... 6- 2
Hard Starting ................................................................................................................. 6- 2
Engine Compression Test Procedure ......................................................................... 6- 3
Rough Engine Idling or Engine Stalling ...................................................................... 6- 4
Rough Engine Running ................................................................................................ 6- 5
Hesitation....................................................................................................................... 6- 6
Engine Lacks Power ..................................................................................................... 6- 7
Engine Noisy ................................................................................................................. 6- 8
Abnormal Noise Due to Hydraulic Lash Adjustor ...................................................... 6- 9
Troubleshooting Procedure ......................................................................................... 6- 9
Abnormal Combustion.................................................................................................. 6-11
Engine Oil Consumption Excessive ............................................................................ 6-12
Fuel Consumption Excessive ...................................................................................... 6-13
Oil Problems .................................................................................................................. 6-13
Engine Oil Pressure Check .......................................................................................... 6-13
Malfunction Indicator Lamp ......................................................................................... 6-14

ENGINE DIAGNOSIS (C24SE) 6-13
Fuel Consumption Excessive
Condition Possible cause Correction
Trouble in fuel system Mixture too rich or too lean due to
trouble in fuel injection system Refer to "Abnormal Combustion"
Fuel cut function does not act Refer to "Abnormal Combustion"
Trouble in ignition system Misfiring or abnormal combustion
due to trouble in ignition system Refer to Hard Start or Abnormal
Combustion Troubleshooting
Guide
Others Engine idle speed too high Reset Idle Air Control Valve
Returning of accelerator control
sluggish Correct
Fuel system leakage Correct or replace
Clutch slipping Correct
Brake drag Correct
Selection of transmission gear
incorrect Caution operator of incorrect gear
selection
Oil Problems
Condition Possible cause Correction
Oil pressure too low Wrong oil in use Replace with correct engine oil
Relief valve sticking Replace
Oil pump not operating properly Correct or replace
Oil pump strainer clogged Clean or replace strainer
Oil pump worn Replace
Oil pressure gauge defective Correct or replace
Crankshaft bearing or connecting
rod bearing worn Replace
Oil contamination Wrong oil in use Replace with new engine oil
Oil filter clogged Replace oil filter
Cylinder head gasket damage Replace gasket
Burned gases leaking Replace piston and piston rings or
rebore cylinders
Oil not reaching valve system Oil passage in cylinder head or
cylinder body clogged Clean or correct

Engine Oil Pressure Check
1. Check for dirt, gasoline or water in the engine
oil.
a. Check the viscosity of the oil.
b. Change the oil if the viscosity is outside the
specified standard.
c. Refer to the "Maintenance and Lubrication"
section of this manual.
2. Check the engine oil level.
The level should fall somewhere between the
"ADD" and the "FULL" marks on the oil level
dipstick.
If the oil level does not reach the "ADD" mark on
the oil level dipstick, engine oil must be added. 3. Remove the oil pressure unit.
4. Install an oil pressure gauge.
5. Start the engine and allow the engine to reach
normal operating temperature (About 80
C).
6. Measure the oil pressure.
Oil pressure should be:
150 kPa(21.8 psi) at idle speed.
7. Stop the engine.
8. Remove the oil pressure gauge
9. Install the oil pressure unit.
10. Start the engine and check for leaks.