1988-2002 Isuzu KB/TF OEM Service & Repair Manual

WORKSHOP MANUAL TF SERIES ENGINE 4JA1/4JH1-TC SECTION 6

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

6 – 2 TROUBLESHOOTING Basic Inspection Procedure Follow the under inspection procedure, when the problem vehicle comes workshop. Step Inspection point Inspection result YES NO 1 Check the check engine lamp Is the check engine lamp turn ON ? Go to section 6E “On Board Diagnostic (OBD) System Check" Go to Step 2 2 The battery fluid level and the gravity Was the problem found? Re-charge the battery or replace the battery Go to Step 3 3 The engine coolant capacity Was the problem found? Replenish the engine coolant Go to Step 4 4 The engine oil level Was the problem found? Replenish the engine oil Go to Step 5 5 The air cleaner element Was the problem found? Clean or replace Go to Step 6 6 The piping fixing condition (oil, vacuum and fuel piping) Was the problem found? Return normal condition Go to Step 7 7 The drive belt tension and break Was the problem found? Re-adjust the tension or replace Go to Step 8 8 Go to section 6E “On Board Diagnostic (OBD) System Check” Was the problem found? Verify repair Go to Step 9 9 Go to mechanical troubleshooting chart Was the problem found? Verify repair —

TROUBLESHOOTING 6 – 3 1. Hard Starting Inspect the following items before diagnosis. 1. The battery conditions. The terminal connection condition. The battery charge condition or battery power weakness. 2. The fan belt loosen or broken. 3. The main fuse condition (open or not). 4. Fuel quantity level. 1–1 Starter motor inoperative Step Action Value(s) Yes No 1 Check the starter switch. Does the starter switch work? — Go to Step 2 Repair or replace the starter switch 2 Check the starter relay. Does the starter relay work? — Go to Step 3 Repair or replace the starter relay 3 Check the magnetic switch. Does the magnetic switch work? — Go to Step 4 Repair or replace the magnetic switch 4 Check the pinion gear condition on the starter motor. Was the condition normal? — Go to Step 5 Replace the pinion gear 5 Check the brush wear or brush spring weakness. Was the condition normal? — Replace the starter motor assembly Repair or replace the brush or brush spring 1-2 Starter motor operates but engine does not turn over Step Action Value(s) Yes No 1 Check the engine internal seizure. Was the engine seized? — Repair or replace seized parts Check other DTC by Tech 2 and go to indicated DTC

6 – 4 TROUBLESHOOTING 1-3 Engine turn over but does not start engine Incase of the fuel not being delivered to the injection pump Step Action Value(s) Yes No 1 Check clogged, damaged the fuel piping or the connector loosen. Was any problem found? — Repair replace problem parts. Go to Step 2 2 Was the over flow valve on the fuel filter closed? — Repair replace the over flow valve Go to Step 3 3 Was the fuel filter element clogged? — Replace the fuel filter element Go to Step 4 4 Was the fuel line air bled? — Go to Step 5 Bleed the air 5 Are any DTC stored? — Go to indicated DTC Solved Incase of the fuel is being delivered to the injection pump Step Action Value(s) Yes No 1 Was the water contain in the fuel? — Replace the fuel Go to Step 2 2 Was the fuel line air bled? — Go to Step 5 Bleed the air 3 Was the injection spray condition complete? — Go to Step 4 Replace the injection nozzle 4 Was the injection nozzle injection starting pressure OK? (See below) Go to Step 5 Replace the injection nozzle 5 Was the injection nozzle sticking? — Replace the injection nozzle Go to Step 6 6 Are any DTC stored? — Go to indicated DTC Solved Injection nozzle opening pressure 1st = 19.5 MPa (199 kg/cm 2 , 2828 psi)

TROUBLESHOOTING 6 – 5 2. Unstable Idling Step Action Value(s) Yes No 1 Was the fuel line air bled completely? — Go to Step 3 Bleed the air 2 Was the fuel line leakage or blockage found? — Repair or replace relation parts. Go to Step 4 3 Was the water contained in the fuel? — Replace the fuel Go to Step 5 4 Was the fuel filter element clogged? — Replace the fuel filter element Go to Step 6 5 Was the injection starting pressure or the injection spray condition OK? (See below) Go to Step 7 Replace the injection nozzle 6 Was the injection nozzle sticking? See Step 6 Replace the injection nozzle Go to Step 8 7 Check the throttle valve condition. Was the idling port clogged in the throttle valve? — Repair or replace the throttle valve Go to Step 9 8 Was the valve clearance improper adjusted? 0.4 mm (0.016 in) both intake and exhaust valves Adjust the valve clearance Go to Step 10 9 Was the compression pressure OK? 3,040 kPa (31 kg/cm 2 , 441 psi) at 200rpm Go to Step 11 Readjust the valve clearance or replace the cylinder head gasket or cylinder liner or piston or piston ring or valve and valve seat 10 Are any DTC stored? — Go to indicated DTC Solved Injection nozzle opening pressure 1st = 19.5 MPa (199 kg/cm 2 , 2828 psi)

6 – 6 TROUBLESHOOTING 3. Insufficient Power Step Action Value(s) Yes No 1 Was the air cleaner element condition OK? (Clogged or not) — Go to Step 2 Clean or replace the air cleaner element. 2 Was the intake air leakage found from intake system? — Repair or replace the intake air system. Go to Step 3 3 Was the fuel filter element condition OK? (Clogged or not) — Go to Step 4 Clean or replace the fuel filter element. 4 Check the fuel injection pipes. Does the injection pipes have obstruction or any damage? — Repair or replace the fuel injection pipes. Go to Step 5 5 Was the water contained in the fuel? — Replace the fuel Go to Step 6 6 Was the injection nozzle pressure or spray pattern normal? — Go to Step 7 Readjust the injection nozzle pressure or replace the nozzle. 7 Was the compression pressure OK? 3.0 MPa (31.0 kg/cm 2 , 441 psi) at 200 rpm Go to Step 8 Readjust the valve clearance or replace the cylinder head gasket or cylinder liner or piston or piston ring or valve and valve seat 8 Was the exhaust pipe clogged? — Repair or replace the exhaust pipe. Go to Step 9 9 Was the exhaust gas leakage found from exhaust system? — Repair or replace the exhaust system. Go to Step 10 10 Was the waste gate control actuator hose broken or cracked? — Replace the hose. Go to Step 11 11 Was the waste gate working completely? — Go to Step 12 Replace the turbocharger assembly. 12 Was turbocharger working completely? — Go to Step 13 Replace the turbocharger assembly. 13 Are any DTC stored? — Go to indicated DTC Solved

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/cm 2 , 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

6 – 8 TROUBLESHOOTING 5. Excessive Oil Consumption Step Action Value(s) Yes No 1 Does the air cleaner element conditon OK? (Clogged or not) — Go to Step 2 Clean or replace the air cleaner element 2 Does PCV (Positive Crankcase Ventilation) Valve has problem? — Repair or replace the relation parts. Go to Step 3 3 Was the oil pressure value more than normal value? Less than 588 kPa (6.0 kg/cm 2 , 85 psi) Repair or replace the oil relief valve Go to Step 4 4 Inspect the front and rear crankshaft oil seal. Was the oil leakage found? — Replace the failure part. Go to Step 5 5 Was the oil leakage found from any gasket? — Replace the wrong gasket Go to Step 6 6 Inspect the valve stem seal, the valve stem and the valve guide for worn. Were any worn found? — Replace the worn part. Go to Step 7 7 Was the oil leakage found from the turbocharger oil seal? — Replace the oil seal. Go to Step 8 8 Was the oil drain pipe of the turbocharger restricted? — Repair or replace the oil drain pipe. Go to Step 9 9 Was the oil drain passage in the turbocharger center housing restricted? — Clean the center housing Go to Step 10 10 Does turbine wheel has any impact damage? — Replace the turbocharger Go to Step 11 11 Are any DTC stored? — Go to indicated DTC Solved

1988-2002 Isuzu KB/TF OEM Service & Repair Manual

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