Fuel Line Troubleshooting - Honda TRX500FM Service Manual

FUEL LINE TROUBLESHOOTING
For the following symptoms, always follow the steps in the troubleshooting flow chart.
- engine slall after warm up the engine
- rough idling after warm up the engine
- engine lacks power after warm up the engine
FUEL SYSTEM
Before starting the inspection, check for pinched or clogged fuel tank breather hose, fuel hose and fuel feed
hose .
1. Fuel pump operation inspection
Tum the ignition switch ON and engine stop switch -OM.
You should hear the fuel pump operation sound for a few seconds.
Is there fuel pump operation sound?
YES - GO TO STEP 3.
NO - GO TO STEP 2.
2. Fuel pump Input Voltage inspection
Inspect the fu el pump input voltage (page 7-13).
Is there battery voltage ?
YES - Faulty fuel pump.
NO open circuit in the Brown wire andlor Green wire.
blown IGN fuse (lOA).
faulty fuel pump relay (page 4-29) and its circuits.
open circuit in the engine stop switch line of the PCM/ECM (page 4-36).
open circuit in the power/ground lines of Ihe PCM/ECM (page 4-35).
3. Fuel flow inspection
Inspect the fuel flow (page 7-12).
Is the fuel flow as speciffed?
YES - GO TO STEP
5.
NO - GO TO STEP 4.
4. Fuel tank strainer screen i nspection
Inspect the fuel tank strainer screen for clogged (page 7-21).
Is the fuel tank strainer screen normal?
YES _ . Replace the fuel pump filter with a new one (page 7-14), and recheck the fuel flow (page 7-12).
If the fuel flow is less than specified, replace the fuel pump (page 7-14).
NO - Clean the strainer screen (page 7-21), and recheck the fuel flow (page 7-12).
5. Fuel pressure inspection
Inspect the fuel pressure (page 7- 11 ).
Is th e fuel pressure as specmed ?
YES _. Inspect the ignition system (page 5-5).
• Inspect the cylinder compression (page 10-7).
NO - Replace the fuel pump with a new one (page 7-14), and recheck.
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