13. FUEL INJECTION SYSTEM Downtown 300i ABS
TROUBLESHOOTING
Engine fail to start Backfiring or misfiring during acceleration
· Intake manifold air leak · Ignition system malfunction
· 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 Poor performance (drive ability) and poor
· Intake air leak fuel economy
· Fuel contaminated/deteriorated · Pinched or clogged fuel hose
· Pinched or clogged fuel hose · Faulty injector
· Idle speed fail to adjust
· Fail to perform PTS/ISC reset
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