BULLETIN NUMBER:
IB17-L-001

IMPORTANT SERVICE
INFORMATION FOR:

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SERVICE MANAGER

ISSUE DATE:
JULY 2017

SERVICE ADVISOR
TECHNICIAN

GROUP:
FUEL AND EXHAUST

PARTS DEPARTMENT
WARRANTY PERSONNEL

DIESEL FUEL CONTAMINATION
AFFECTED VEHICLES


Isuzu Vehicles equipped with:
3.0L (4JJ1) and 5.2L (4HK1) diesel engines
INFORMATION

Damage to fuel systems, including to both low and high pressure components, often
results from fuel contamination. Operating a vehicle’s diesel engine on fuels and
additives that do not meet the vehicle manufacturer’s specifications for lubrication and
cooling, or that have improper anti-corrosion properties, can cause drivability problems
as well as component damage or even failure.
Due to the tight tolerances on modern diesel engines, contaminants such as water can
dilute the lubricating properties of diesel fuel and cause engine damage. For instance,
water can lead to acid forming in the fuel system, which can be extremely caustic and
harmful to the engine.
Contamination of high pressure fuel system components may cause symptoms
including, but not limited to, the following:
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Crank, but no start
Long crank/Hard start
Running rough
Low power
Fuel pressure-related DTCs

Most common sources of contamination:
 Contaminated fuel source
 Above and below ground fuel storage
tanks
 Use of fuel stored for long periods
 Not draining water at proper intervals
Some examples of fuel contamination:

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DPF unable to regenerate
Engine knocking
Exhaust smoke
Fuel rail pressure (FRP) slow to build

 Fueling errors (e.g. introducing
gasoline or DEF fluid into the fuel tank/s)
 Decomposing Bio-diesel
 Improperly positioned fuel filler neck
 Improperly installed rollover valve

Identifiable in shop
Water content exceeds specification
DEF (Diesel Exhaust Fluid)
Gasoline
Organic Growth (Bacteria, Fungus)

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May require external testing
 Aged/Oxidized Fuel
 Unapproved fuel additives
 Fuel with High TAN (Total Acid
Number) – Acidic Fuel

NOTE: If you are unable to identify the contaminant it may be necessary to send a
sample of fuel out to a fuel analysis lab for contamination identification.

SERVICE PROCEDURE
CONTAMINATION DIAGNOSIS CHART
Step
Action

1

Obtain a fuel sample from the Water
Separator using a clean, clear, dry
container that is appropriate for holding
fuel. Allow the fuel sample to sit for
approximately 15 minutes. Compare the
sample to the photos of contaminated fuel
in Table 1.

Value(s)

Yes

No

See photos
in Table 1

Go to
Step 2

Go to
Step 3

Go to
Step 4

Go to
Step 3

Go to
Step 4

Go to
Procedure
B

Go to
Diagnostic
Aides

System
OK

Does the fuel appear to be contaminated?

2

Follow the recommended procedure based
on the appearance of the fuel as compared
to the photos in Table 1 and repair as
necessary.
Was a problem found and corrected?

3

Obtain a fuel sample from the bottom of
the fuel tank(s). Perform a specific gravity
test and record the results.
Is the reading within specification?

API Gravity
No1 Diesel
39-44
No2 Diesel
30-39

1. Clear any DTCs with a scan tool.
2. Turn OFF the ignition for 30 seconds.
4

3. Start the engine.
Are there any DTCs or conditions that you
have not diagnosed?

TABLE 1
Condition

Image

Note

Procedure

Red, orange,
brown debris.
Cloudy
Rust

B

Grainy
sedimentation
Metal components
may have rust on
them
Sedimentation in
fuel tank.

Organic

B

May have floating
particles.
Powdery
sedimentation

No visual
difference.

Gasoline

B

May smell like
gasoline.

Diesel and Water
will separate with
the diesel fuel on
top.
Water

B

Appears cloudy.

Diesel and DEF
will separate with
the diesel fuel on
top.
DEF

A

Perform DEF
Contamination
Check.

DEF CONTAMINATION CHECK
1. If the contaminant is suspected to be DEF, verify by removing the Water

Separator Cover, Primary Fuel Filter Element, and let the element and cover
dry for two (2) hours. If DEF is present, crystalized DEF may be visible inside
the Water Separator Cover, Upper Housing, Primary Fuel Filter and the
Secondary Fuel System ports. See Figure 1 for reference.


If DEF contamination is found during inspection follow Procedure A to
repair the vehicle.



If no there is no indication of DEF contamination follow Procedure B,

Figure 1. Filter coated in urea crystals from
DEF.

PROCEDURE A – WATER OR DEF CONTAMINATION
1.
2.
3.
4.
5.

Remove cap from fuel tank.
Disconnect suction line from the water separator.
Use air to push fuel and contaminants into fuel tank.
Reconnect suction line to water separator.
Clean the fuel tank.


Drain fuel into an appropriate storage container.



Remove fuel tank. Refer to workshop manual for procedure.



Inspect fuel tank for signs of damage, (example: water = rust).



Thoroughly clean the fuel tank.



Install fuel tank. Refer to workshop manual for procedure.

 Fill fuel tank to ¼ full with clean, fresh, and good quality diesel fuel.
IMPORTANT: To prevent contaminated fuel from re-entering the system, be
sure to remove all contaminated fuel from the fuel tank.

IMPORTANT: Be sure to properly dispose of contaminated fuel in accordance to
local laws and guidelines.
6. Replace both the sedimenter cartridge and fuel filter.
On 4HK1 remove, inspect the fuel screen on the back of the fuel pump for
signs of damage due to fuel contamination.
7. Replace all metal high pressure fuel system components.
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Fuel pump

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Injector lines

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Fuel rail

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Fuel injectors

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Injector return hose

 4HK1, replace fuel screen on back of fuel pump
NOTE: If there are no signs of physical damage, the low pressure fuel lines can
be reused.
8. Disconnect the return line to fuel tank.
9. Place return line into a suitable recovery container at least 2 gallons in size.
10. Disable fuel injectors.


3.0L: Disconnect individual injectors on the top of the cylinder head
cover. See Figure 8.

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5.2L: Disconnect all injectors by disconnecting harness connector
H108. See Figure 9.

Figure 8: 4JJ1 connectors E5, E6, E7,
and E8

Figure 9: 4HK1 connector H108

11. Crank the engine in 30 second time intervals, with a 1 minute cool down in
between, until 1 gallon of fuel has accumulated into the recovery container.
12. Reconnect the fuel return line.
13. Reconnect the fuel injectors. Refer to workshop manual for procedure.
14. Attempt to start the engine.


If the engine starts, let it run for 15 minutes. Verify injector balance
rates are normal. Check for engine noise. Verify proper fuel pressure
track.



On a 4HK1 verify proper low side fuel pressure.

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If the engine does not start, go to the hand primer pump and operate
approx., 30 strokes, or until there is firm resistance. Re-attempt engine
start.
15. Stop engine
16. Clean any fuel spillage from engine.
17. Bleed fuel system. Refer to workshop manual for procedure.
18. Start vehicle and check that there are no fuel system leaks. Repair as
necessary.
19. Return to Step 4 of the Contamination Diagnosis Chart

PROCEDURE B - Organic, Rust, Gasoline or Kerosene Contamination
1. Remove cap from fuel tank.
2. Disconnect suction line from the water separator.
3. Use air to push fuel and contaminants into fuel tank.
4. Reconnect suction line to water separator.
5. Clean the fuel tank.


Drain fuel into an appropriate storage container.



Remove fuel tank. Refer to workshop manual for procedure.



Inspect fuel tank for signs of damage, (example: water = rust).



Thoroughly clean the fuel tank.



Install fuel tank. Refer to workshop manual for procedure.



Fill fuel tank to ¼ full with clean, fresh, and good quality diesel fuel.

6. Disconnect the return line to fuel tank.
7. Place return line into a suitable recovery container at least 2 gallons in size.
8. Disable fuel injectors.


3.0L: Disconnect individual injectors on the top of the cylinder head
cover. See Figure 8.



5.2L: Disconnect all injectors by disconnecting harness connector
H108. See Figure 9.

9. Crank the engine in 30 second time intervals, with a 1 minute cool down in
between, until 1 gallon of fuel has accumulated into the revcovery container.
10. Reconnect the fuel return line.
11. Reconnect the fuel injectors. Refer to workshop manual for procedure.
12. Attempt to start the engine.


If the engine starts, let run for 15 minutes. Verify injector balance rates
are normal. Check for engine noise. Verify proper fuel pressure track.



On a 4HK1 verify proper low side fuel pressure.



If the engine does not start, go to the hand primer pump and operate
approx., 30 strokes, or until there is firm resistance. Re-attempt engine
start.
13. Stop engine
14. Clean any fuel spillage from engine.
15. Bleed fuel system. Refer to workshop manual for procedure.
16. Start vehicle and check that there are no fuel system leaks. Repair as
necessary.
17. Return to Step 4 of the Contamination Diagnosis Chart