Isuzu 20LE - Yes no; Fuel System Diagnosis; Verify Repair Go to Step

6E1-120 DRIVEABILITY AND EMISSIONS
Fuel System Diagnosis (Cont'd)
Step Action Value(s) Yes No
8
Replace the fuel pump.
Is the action complete?
-
Verify repair
-
9
1. Disconnect the vacuum hose from the fuel pressure
regulator.
2. With the engine idling, apply 12-14 inches of vacuum to
the fuel pressure regulator.
Does the fuel pressure indicated by the fuel pressure
gauge drop by the amount specified?
21-105 kPa
(3-15 psi) Go to Step 10 Go to Step 11
10
Locate and repair the loss of vacuum to the fuel pressure
regulator.
Is the action complete?
-
Verify repair
-
11
Replace the fuel pressure regulator.
Is the action complete?
-
Verify repair
-
12
1. Run the fuel pump with the Scan Tool.
2. After pressure has built up, turn off the pump and
clamp the supply hose shut with suitable locking pliers.
Does the fuel pressure indicated by the fuel pressure
gauge remain constant?
-
Go to Step 13 Go to Step 15
13
Visually inspect the fuel supply line and repair any leaks.
Was a problem found?
-
Verify repair
Go to STep
14
14
Remove the fuel tank and inspect for leaky hose or in-tank
fuel line.
Was a problem found?
-
Verify repair Go to STep 8
15
1. If the pliers are still clamped to the fuel supply hose,
remove the locking pliers.
2. With suitable locking pliers, clamp the fuel return line to
prevent fuel from returning to the fuel tank.
3. Run the fuel pump with the Scan Tool.
4. After pressure has built up, remove power to the pump.
Does the fuel pressure indicated by the fuel pressure
gauge remain constant?
-
Go to Step 11 Go to Step 16
16
Locate and replace any leaking fuel injector(s).
Is the action complete?
-
Verify repair
-
17
Is the fuel pressure indicated by the fuel pressure gauge
above the specified limit?
376 kPa
(55 psi) Go to Step 18 Go to Step 21
18
1. Relieve the fuel pressure. Refer to the Fuel Pressure
Relief.
2. Disconnect the fuel return line from the fuel rail.
3. Attach a length of flexible hose to the fuel rail return
outlet passage.
4. Place the open end of the flexible hose into an
approved gasoline container.
5. Run the fuel pump with the Scan Tool.
6. Observe the fuel pressure indicated by the fuel
pressure gauge with the fuel pump running.
Is the fuel pressure within the specified limits?
290-376 kPa
(42-55 psi) Go to Step 19 Go to Step 20