Mercury MerCruiser MCM 454 Mag MPI Service Manual page 668

SERVICE MANUAL NUMBER 23
Chart A-4 (4 of 5): Fuel System DiagnosisContinued)
Index
90-861326--1 MARCH 1999
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Ignition "OFF" for 10
1.
seconds.
Ignition "ON."
2.
Block fuel pressure
3.
line between the fuel
7
pump and fuel rail us-
ing fuel shut-off valve
tool.
Does fuel pressure
hold?
Ignition "OFF" for 10
1.
seconds.
Ignition "ON."
2.
Block fuel return line
3.
8
using fuel
valve tool.
Does fuel pressure
hold?
Is fuel pressure below
9
specified value?
Check for restricted fuel
lines. If a problem is
found, repair as neces-
10
sary.
Was a problem found?
Ignition "OFF"
1.
Block fuel return line
2.
using fuel
valve tool.
11
Ignition "ON."
3.
Does fuel pressure rise
above the specified
value?
–
shut-off
–
34 psi (234 kPa)
–
shut-off
38 psi (262 kPa)
GENERAL SYSTEM DIAGNOSTICS
Go to Step 18 Go to Step 8
Go to Step 16 Go to Step 15
Go to Step 10 Go to Step 12
Go to OBD
Go to Step 11
System Check
Go to Step 16 Go to Step 18
Page 5E-75