Daihatsu F300 Service Manual page 1169

ENGINE MECHANICALS
(2) Measurement of HC/CO concentrations at idle.
Wait at least one minute before the measurement so as to allow concentrations to stabilize.
Complete the measurement within three minutes.
If the HC/CO concentrations dose not conform to the regulations, see the following table for possible
causes.
Trouble shooting
HC
co
Problems Possible causes
High Normal Rough idle 1. Faulty ignition
• Incorrect timing
• Fouled, shorted or improperly gapped spark plugs
• Open or crossed high tension cords
• Cracked distributor cap
2. Incorrect valve clearance
3. Leaky EGR valve (US. spc. only)
4. Leaky exhaust valves
5.
Leaky cylinder
High Low Rough idle
1. Lean mixture causing misfire
(Fluctuating HC reading)
High High Rough idle 1. Restricted air filter
(Black smoke from
exhaust) 2. Faulty EA system
• Faulty pressure regulator
• Clogged fuel return line
• Defective water temp. sensor
• Defective air temp. sensor
• Faulty throttle position sensor
• Faulty pressure sensor
• Faulty injector
• Faulty ECU
3. Insufficient warmed up three way catalyst
EM-28
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