Troubleshooting
If the HC/CO concentration does not comply with regulations,
perform troubleshooting in the order given below.
(a) Check oxygen sensor operation.
(See page
)
(b) See the table below for possible causes, and then
inspect and correct the applicable causes if necessary.
HC
CO
Problem
Cause
High
Normal
Rough idle
1. Faulty ignition:
High
Normal
Rough idle
1. Faulty ignition:
D
Incorrect timing
g
D
Fouled, shorted or improperly gapped plugs
,
y g
g
D
Open or crossed high–tension cords
O en or crossed high tension cords
D
Cracked distributor cap
Cracked distributor ca
2. Incorrect valve clearance
2. Incorrect valve clearance
3. Leaky EGR valve
L
k i
k
d
h
l
y
4. Leaky intake and exhaust valves
5 L
k
li d
y
5. Leaky cylinder
High
Low
Rough idle
1. Vacuum leak:
High
Low
Rough idle
(Fluctuating HC reading)
1. Vacuum leak:
D
PCV hose
(
g
g)
D
EGR valve
D
Intake manifold
Intake manifold
D
Air intake chamber
Air intake chamber
D
Throttle body
D
Throttle body
D
ISC valve
D
ISC valve
D
Brake booster line
D
Brake booster line
2. Lean mixture causing misfire
High
High
Rough idle
1. Clogged air filter
High
High
Rough idle
(Black smoke from exhaust)
1. Clogged air filter
2. Faulty EFI system
F
lt
l t
(
)
y
y
D
Faulty pressure regulator
Cl
d f
l
li
D
Clogged fuel return line
gg
D
Defective water temp. sensor
D
Defective air temp. sensor
D
Faulty ECU
y
D
Faulty injector
Faulty injector
D
Faulty cold start injector
Faulty cold start injector
D
Faulty throttle position sensor
D
Faulty throttle osition sensor
D
Air flow meter
EM-13
ENGINE MECHANICAL – Idle and/or 2,500 rpm HC/CO Concentration Check Method
Summary of Contents for 2VZ-FE
Page 1: ...ENGINE MECHANICAL EM 1 ENGINE MECHANICAL Description Operation ...
Page 31: ...CYLINDER HEADS COMPONENTS EM 29 ENGINE MECHANICAL Cylinder Heads ...
Page 63: ...CYLINDER BLOCK REMOVAL OF ENGINE EM 61 ENGINE MECHANICAL Cylinder Block ...
Page 64: ...EM 62 ENGINE MECHANICAL Cylinder Block ...
Page 71: ...COMPONENTS EM 69 ENGINE MECHANICAL Cylinder Block ...
Page 106: ...EFI SYSTEM FI 1 ...
Page 107: ...DESCRIPTION FI 2 EFI SYSTEM Description ...
Page 111: ...OPERATION System Circuit FI 4 EFI SYSTEM Operation System Circuit ...
Page 121: ...FUEL SYSTEM Fuel Pump EFI SYSTEM Fuel System Fuel Pump FI 15 ...
Page 141: ...Fuel Tank and Lines COMPONENTS EFI SYSTEM Fuel System Fuel Tank and Lines FI 35 ...
Page 172: ...EXHAUST SYSTEM EXHAUST SYSTEM REPAIR INSTRUCTIONS EX 1 ...
Page 174: ...EMISSION CONTROL SYSTEMS EC 1 ...
Page 186: ...COOLING SYSTEM CO 1 ...
Page 205: ...LUBRICATION SYSTEM LUBRICATION SYSTEM Description Operation LU 1 ...
Page 224: ...IGNITION SYSTEM IG 1 ...
Page 237: ...SERVICE SPECIFICATIONS IG 14 IGNITION SYSTEM ServiceSpecifications ...
Page 238: ...ENGINE TROUBLESHOOTING TR 1 ...