Toyota 22R-E Service Manual page 47

Normal
High
High Low
High
High
ENGINE
TROUBLESHOOTING
If the HC/CO concentration does not comply with
regulations, perform troubleshooting in the order
given below.
1. Check oxygen sensor operation
(See page EG1–212)
2. See the table below for possible cause, and then
inspect and correct the applicable causes if neces–
sary.
Symptoms
Rough idle
Rough idle
(Fluctuating HC reading)
Rough idle
(Black smoke from exhaust)
– ENGINE MECHANICAL
Causes
1. Faulty ignition:
Incorrect timing
Fouled, shorted or improperly gapped plugs
Open or crossed high–tension cords
Cracked distributor cap
2. Incorrect valve clearance
3. Leaky EGR valve
4. Leaky exhaust valves
5. Leaky cylinder
1. Vacuum leak:
Vacuum hose
Intake manifold
Intake chamber
PCV line
Throttle body
1. Clogged air filter
2. Plugged PCV valve
3. Pulsed Secondary Air Injection (PAIR)
system problems
4. Faulty MFI system:
Faulty pressure regulator
Clogged fuel return line
Faulty volume air flow meter
Defective engine coolant temp. sensor
Defective intake air temp. sensor
Faulty ECM
Faulty injector
Faulty cold start injector
EG1–13