MECHANICAL(H4DO) > Engine Trouble in General
INSPECTION
NOTE:
The “RANK” shown in the chart shows the possibilities of the cause of trouble in order from “Very often” to “Rarely”.
A — Very often
B — Sometimes
C — Rarely
Symptoms | Problem parts etc. | Possible cause | RANK |
1. Engine does not start. | |||
1) Starter does not turn. | Starter | Defective battery-to-starter harness | B |
Defective starter switch | C | ||
Defective inhibitor switch | C | ||
Defective starter | B | ||
Battery | Improper connection of terminal | A | |
Run-down battery | A | ||
Defective charging system | B | ||
Friction | Seizure of crankshaft and connecting rod bearing | C | |
Seized camshaft | C | ||
Seized or stuck piston and cylinder | C | ||
Immobilizer system Basic Diagnostic Procedure"> | A | ||
2) Initial combustion does not occur. | Starter | Defective starter | C |
Engine control system Basic Diagnostic Procedure"> | A | ||
Fuel line | Defective fuel pump and relay | A | |
Clogged fuel line | C | ||
Lack of fuel or insufficient fuel | B | ||
Timing chain | Trouble | B | |
Defective timing | B | ||
Compression | Incorrect cam clearance | C | |
Loosened spark plug or defective gasket | C | ||
Loosened cylinder head bolt or defective cylinder head gasket | C | ||
Improper valve sealing | C | ||
Defective valve stem | C | ||
Worn or broken valve spring | B | ||
Worn or stuck piston rings, cylinder liner and piston | C | ||
Incorrect valve timing | B | ||
Improper engine oil (low viscosity) | B | ||
3) Initial combustion occurs. | Engine control system Basic Diagnostic Procedure"> | A | |
Intake system | Defective intake manifold gasket | B | |
Defective throttle body gasket | B | ||
Fuel line | Defective fuel pump and relay | C | |
Clogged fuel line | C | ||
Lack of fuel or insufficient fuel | B | ||
Timing chain | Trouble | B | |
Defective timing | B | ||
Compression | Incorrect cam clearance | C | |
Loosened spark plug or defective gasket | C | ||
Loosened cylinder head bolt or defective cylinder head gasket | C | ||
Improper valve sealing | C | ||
Defective valve stem | C | ||
Worn or broken valve spring | B | ||
Worn or stuck piston rings, cylinder liner and piston | C | ||
Incorrect valve timing | B | ||
Improper engine oil (low viscosity) | B | ||
4) Engine stalls after initial combustion. | Engine control system Basic Diagnostic Procedure"> | A | |
Intake system | Loosened or cracked intake duct | B | |
Loosened or cracked PCV hose | C | ||
Loosened or cracked vacuum hose | C | ||
Defective intake manifold gasket | B | ||
Defective throttle body gasket | B | ||
Dirty air cleaner element | C | ||
Fuel line | Clogged fuel line | C | |
Lack of fuel or insufficient fuel | B | ||
Timing chain | Trouble | B | |
Defective timing | B | ||
Compression | Incorrect cam clearance | C | |
Loosened spark plug or defective gasket | C | ||
Loosened cylinder head bolt or defective cylinder head gasket | C | ||
Improper valve sealing | C | ||
Defective valve stem | C | ||
Worn or broken valve spring | B | ||
Worn or stuck piston rings, cylinder and piston | C | ||
Incorrect valve timing | B | ||
Improper engine oil (low viscosity) | B | ||
2. Rough idle and engine stall | Engine control system Basic Diagnostic Procedure"> | A | |
Intake system | Loosened or cracked intake duct | A | |
Loosened or cracked PCV hose | A | ||
Loosened or cracked vacuum hose | A | ||
Defective intake manifold gasket | B | ||
Defective throttle body gasket | B | ||
Defective PCV valve | C | ||
Loosened oil filler cap | B | ||
Dirty air cleaner element | C | ||
Fuel line | Defective fuel pump and relay | C | |
Clogged fuel line | C | ||
Lack of fuel or insufficient fuel | B | ||
Timing chain | Defective timing | C | |
Compression | Incorrect cam clearance | B | |
Loosened spark plug or defective gasket | B | ||
Loosened cylinder head bolt or defective cylinder head gasket | B | ||
Improper valve sealing | B | ||
Defective valve stem | C | ||
Worn or broken valve spring | B | ||
Worn or stuck piston rings, cylinder and piston | B | ||
Incorrect valve timing | A | ||
Improper engine oil (low viscosity) | B | ||
Lubrication system | Incorrect oil pressure | B | |
Defective rocker cover gasket | C | ||
Cooling system | Over-heating | C | |
Other | Evaporative emission control system malfunction | A | |
Stuck or damaged throttle valve | B | ||
3. Low output, hesitation and poor acceleration | Engine control system Basic Diagnostic Procedure"> | A | |
Intake system | Loosened or cracked intake duct | A | |
Loosened or cracked PCV hose | A | ||
Loosened or cracked vacuum hose | B | ||
Defective intake manifold gasket | B | ||
Defective throttle body gasket | B | ||
Defective PCV valve | B | ||
Loosened oil filler cap | B | ||
Dirty air cleaner element | A | ||
Fuel line | Defective fuel pump and relay | B | |
Clogged fuel line | B | ||
Lack of fuel or insufficient fuel | C | ||
Timing chain | Defective timing | B | |
Compression | Incorrect cam clearance | B | |
Loosened spark plug or defective gasket | B | ||
Loosened cylinder head bolt or defective cylinder head gasket | B | ||
Improper valve sealing | B | ||
Defective valve stem | C | ||
Worn or broken valve spring | B | ||
Worn or stuck piston rings, cylinder and piston | C | ||
Incorrect valve timing | A | ||
Improper engine oil (low viscosity) | B | ||
Lubrication system | Incorrect oil pressure | B | |
Cooling system | Over-heating | C | |
Over-cooling | C | ||
Other | Evaporative emission control system malfunction | A | |
4. Surging | Engine control system Basic Diagnostic Procedure"> | A | |
Intake system | Loosened or cracked intake duct | A | |
Loosened or cracked PCV hose | A | ||
Loosened or cracked vacuum hose | A | ||
Defective intake manifold gasket | B | ||
Defective throttle body gasket | B | ||
Defective PCV valve | B | ||
Loosened oil filler cap | B | ||
Dirty air cleaner element | B | ||
Fuel line | Defective fuel pump and relay | B | |
Clogged fuel line | B | ||
Lack of fuel or insufficient fuel | C | ||
Timing chain | Defective timing | B | |
Compression | Incorrect cam clearance | B | |
Loosened spark plug or defective gasket | C | ||
Loosened cylinder head bolt or defective cylinder head gasket | C | ||
Improper valve sealing | C | ||
Defective valve stem | C | ||
Worn or broken valve spring | C | ||
Worn or stuck piston rings, cylinder and piston | C | ||
Incorrect valve timing | A | ||
Improper engine oil (low viscosity) | B | ||
Cooling system | Over-heating | B | |
Other | Evaporative emission control system malfunction | C | |
5. Engine does not return to idle. | Engine control system Basic Diagnostic Procedure"> | A | |
Intake system | Loosened or cracked vacuum hose | A | |
Other | Stuck or damaged throttle valve | A | |
6. Dieseling (run-on) | Engine control system Basic Diagnostic Procedure"> | A | |
Cooling system | Over-heating | B | |
Other | Evaporative emission control system malfunction | B | |
7. After burning in exhaust system | Engine control system Basic Diagnostic Procedure"> | A | |
Intake system | Loosened or cracked intake duct | C | |
Loosened or cracked PCV hose | C | ||
Loosened or cracked vacuum hose | B | ||
Defective PCV valve | B | ||
Loosened oil filler cap | C | ||
Timing chain | Defective timing | B | |
Compression | Incorrect cam clearance | B | |
Loosened spark plug or defective gasket | C | ||
Loosened cylinder head bolt or defective cylinder head gasket | C | ||
Improper valve sealing | B | ||
Defective valve stem | C | ||
Worn or broken valve spring | C | ||
Worn or stuck piston rings, cylinder and piston | C | ||
Incorrect valve timing | A | ||
Lubrication system | Incorrect oil pressure | C | |
Cooling system | Over-cooling | C | |
Other | Evaporative emission control system malfunction | C | |
8. Knocking | Engine control system Basic Diagnostic Procedure"> | A | |
Intake system | Loosened oil filler cap | B | |
Timing chain | Defective timing | B | |
Compression | Incorrect cam clearance | C | |
Incorrect valve timing | B | ||
Cooling system | Over-heating | A | |
9. Excessive engine oil consumption | Intake system | Loosened or cracked PCV hose | A |
Defective PCV valve | B | ||
Loosened oil filler cap | C | ||
Compression | Defective valve stem | A | |
Worn or stuck piston rings, cylinder and piston | A | ||
Lubrication system | Loosened chain cover attaching bolts and defective gasket | B | |
Defective oil filter gasket | B | ||
Defective crankshaft oil seal | B | ||
Defective rocker cover gasket | B | ||
Loosened oil drain plug or defective gasket | B | ||
Loosened oil pan mounting bolt or defective oil pan | B | ||
10. Excessive fuel consumption | Engine control system Basic Diagnostic Procedure"> | A | |
Intake system | Dirty air cleaner element | A | |
Timing chain | Defective timing | B | |
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