Fuel System (Pgm-Fi) Symptom Troubleshooting - Honda MUV700 big red Service Manual

FUEL SYSTEM (PGM-FI)
SYMPTOM TROUBLESHOOTING
When the vehicle has one of these symptoms, check the OTC or MIL blinking, refer to the DTe index (page 6-14) and begin
the appropriate troubleshooting procedure. If there are no OTC/Mll blinking stored in the PCM memory, do the diagnostic
procedure for the symptom, in the sequence listed below, until you find the cause.
Symptom
Engine cranks but won't
start
(No OTC and Mil blinking)
Engine cranks but won't
start
(No fuel pump operation
sound when turning the
ignition switch to ON
(I))
Engine stalls. hard to start,
rough idling
Backfiring or misfiring dur-
ing acceleration
Poor performance
(driveability) and pOor fuel
economy
Idle speed is below specifi-
cations or fast idle too low
(No OlC and MIL blinking)
Idle speed is above specifi-
cations or fast idle too high
(No DTC and MIL blinking)
MIL stays on but no OTCs
set, or MIL never comes
ON at all
MIL stays on at all times
(No OTC set)
6-6
Diagnosis rocedure
1.
Inspect the ignition system
~page
22-5).
2. Inspect the fuel supply system
(page 6·31).
1.
PCM power/ground ci rcuits
malfunction ~page 6-54).
2. Inspect the fuel pump system
(page 6·36) .
1. Check the idle speed
~page
6·
55).
2. Check the IACV (page 6-48).
3. Inspect the fuel supply system
(page 6-31).
Check the ignition system.
1.
Inspect the fuel supply system
(page 6-31).
2. Check the air cleaner for clog-
ging (page 4-6).
1. Check the idle speed (p age 6·
55).
2. Check the IACV (page 6-48).
1. Check the idle speed (page 6-
55)
2. Check the accelerat or pedal
operation and pedal freeplay
(page 4·5).
3.
Check the IACV (page 6·48).
Troubleshoot the MIL circuit
(page 6-30).
Check the DlC circuit (Brown/red
wire) for short circuit.
Also check for
• No fuel to fuel injector
"--- - -----1
- Clogged fuel filter
- Pinched or clogged fuel feed hose
- Pinched or clogged fuel tank breather
hose
- Faulty fuel pump
- Faulty fuel pump circuits
• Intake air leak
• Contaminated/deteriorated fuel
• Faulty fuel injector
• IACV stuck closed
• Open ci rcu it in the power input (BlaclUgreen)
andlor ground ~Green) wire of the PCM
• Faulty main relay or related circuit
• Faulty ignition switcn or related circui t
•
Blown FI fuse (10 A)
•
Blown IGN fuse (10 A)
•
Restricted fuel feed hose
•
Contaminated/deteriorated fuel
•
Intake air leak
•
Restricted fuel tank breather hose
•
Faulty ignition system
•
Faulty ignition system
•
Pindled or dogged fuel feed hose
•
Fau lty injector
•
Fau lty ignition system
•
IACV stuck dosed
•
Faulty fuel supply syst em
•
Faulty ignition syst em
•
Valve clearance
•
IACV stuck opened
•
Fau lty ignition system
•
Intake air leak
•
Engine top end problem
•
Clogged air cleaner
•
Valve clearance
•
Faulty Mil circuit
•
Short circuit in the OLC related wire
-