Troubleshooting - KYMCO Downtown 300i ABS Service Manual

13. FUEL INJECTION SYSTEM

TROUBLESHOOTING

Engine fail to start
• Intake manifold air leak
• Fuel contaminated/deteriorated
• Pinched or clogged fuel hose
• Faulty fuel pump
• Clogged fuel filter, throttle body
• Sticking fuel injector needle
• Faulty fuel pump operating system
• Carbon deposit stayed on the fuel injector
• Spark plug dirty
• Fuel pressure incorrect
Engine stall, hard to start, rough idling
• Intake air leak
• Fuel contaminated/deteriorated
• Pinched or clogged fuel hose
• Idle speed fail to adjust
• Fail to perform PTS/ISC reset
Backfiring or misfiring during acceleration
• Ignition system malfunction
Poor performance (drive ability) and poor
fuel economy
• Pinched or clogged fuel hose
• Faulty injector
Downtown 300i ABS
13-6