Kent-Moore J-44175-A User manual

3
Table of Contents
INTRODUCTION
Tool Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Testing diesel fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Tester Set Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Tester Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Converting Digital MultiMeter frequency readings
to ethanol percentage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
DIAGNOSTIC PROCEDURES
Ethanol Blended Fuel (E85) Diagnostic Procedure . . . . . . . . . . . . . . . . . . . . . .9
Obtaining the TWO fuel samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Flush out the gage hose before taking any fuel samples . . . . . . . . . . .13
Testing the first fuel sample
Water and Sediment Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Testing the second fuel sample
Ethanol blended fuel (E85) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Excessive Ethanol Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Follow the appropriate General Motors Diagnostic
Service Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
End Of Test Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Non-Blended Fuel Diagnostic Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Obtaining the TWO fuel samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Flush out the gage hose before taking any fuel samples . . . . . . . . . . .22
Testing the first fuel sample
Water and Sediment Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Testing the second fuel sample
Non-blended, fuel-normal gasoline
Excessive Ethanol Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Follow the appropriate General Motors
Diagnostic Service Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
End Of Test Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Appendixes
Appendix One: Fuel Composition Tester Troubleshooting . . . . . . . . . . . . . . . .27
Appendix Two: Fuel contamination concerns, or red LED on . . . . . . . . . . . . .28
Appendix Three: Technical Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Fuel quality can effect a vehicle’s performance.
Specifically, gasoline and gasoline blends that
are contaminated or contain excessive amounts
of ethanol can effect vehicle driveability, fuel
economy, fuel system components and emissions.
Due to the potential negative impact of poor fuel
quality, it is important for today’s technician to
have the capability to correctly diagnose fuel
related concerns.
Tool Description
The Fuel Composition Tester J-44175-A is a
microprocessor based hand held tester to allow
for accurate analysis of gasoline and gasoline/
ethanol blends. It is easy to use and designed to
be used with a Digital Multi Meter (AC frequency
Hz scale), to quickly indicate the ethanol percentage
of any fuel sample. When testing “E85”, which
should measure between 60% and 91% ethanol,
the tester’s red LED will indicate if the fuel is
contaminated and should be replaced. The red-
colored LED can indicate certain contaminants
such as methanol or very small amounts of salt.*
If methanol is in the fuel, the fuel is contaminated
and should be replaced. Methanol can corrode
metal parts in the fuel system and also can
damage plastic and rubber parts. The J-44175-A
can indicate methanol in one of two ways: either
by frequency measurement above 160, or the red
LED on, or both.
The Fuel Composition Tester
J-44175-A is designed to be used with the
J-39200 Digital Multi Meter (DMM) in order to
display a frequency (Hz) value. This frequency
value is easily converted to indicate ethanol
*During certain atmospheric conditions, it is possible for very small amounts of salty air to enter the vehicle fuel
tank through the evaporative emissions system fresh air vent. If the amount of salt in the fuel becomes
sufficient to light the tester’s red LED, the fuel is contaminated and should be replaced. See “J-44175-A
frequency measures above 160 Hz, and/or the red LED is on” in the appendix.
INTRODUCTION
4

5
percentage by simply subtracting 50 from the “AC
Hz” frequency number displayed on the DMM. The
result is the measured ethanol percentage of the
fuel sample. Use either the J-34730-FF orange-face
pressure gage or the a-48027 Digital Pressure
Gage to obtain the fuel samples (see figure 7).
Follow the instructions included with each pressure
gage. Both gages are ethanol tolerant.
Features
This tester was designed to be used in the shop
environment. It easily sits on the flat surface of a
workbench when in use. It contains a funnel/bowl
which is integrated into the tester housing to
make it easy to pour the fuel sample into the
sensing cell. The tester is lightweight and can be
carried by it’s convenient handle. The tester
has a removable battery cover to allow easy
replacement of the 9 volt alkaline battery which
powers the unit (see figure 1).Here is a description
of the tester’s user interface: (see figure 2)
* Power: Press once to activate the tester. Press
it again to turn off the tester. After the tester is
on for ten minutes, an auto power off function
will turn off the tool to extend battery life.
* Red Fuel Diagnostic LED: When this LED is
on, it indicates there may be a concern with
the fuel sample. If the red LED is on, refer to
“J-44175-A frequency measures above 160
Hz, and/or the red LED is on” in appendix two
of this manual.
* Green Fuel Diagnostic LED: When this
LED is on, it indicates the fuel sample
is acceptable.
Handle
Leg
Bowl
Battery
Compartment
Tip Jacks
Fuel Test Port
Funnel
Fuel Diagnostic LEDs
Low Batt
Fuel
Composition
Tester
Instructions:
1. Press Power button
to activate.
2. Verify that green
LED is on.
3.Connect J 39200
DMM probes to plus
and minus jacks.
4. Select Volts-AC
( ˜v) then the Hz-
Frequency function
on DMM.
5.Follow GM
diagnostic service
procedure.
J-44175
+
Power
Figure 1
Figure 2

6
* Yellow Low Batt LED: This LED is illuminated
to indicate low remaining battery life. When this
LED is ON it means the battery has reached the
end of it’s useful life and must be replaced. The
tool may not work properly, or may give
inaccurate test results if operated with the
yellow LED illuminated.
* Digital Multi Meter connections: The Plus “+”
and Minus “-” at the bottom of the handle
indicate the location of the connector jacks
which are required for the DMM test lead
connections.
NOTE: “needle-point” type probes will not stay
connected into the tester connector jacks.
Calibration
The tester has been calibrated and tested at the
manufacturing facility. It does not require any type
of re-calibrating by the user during the life of the
tester.
Testing diesel fuel
The J-44175-A Fuel Composition Tester is NOT
intended to be used to test diesel fuel.
TESTER SET UP
Remove the J-39200 Digital Multi Meter from it’s
storage case. You will need the general purpose
test leads that are included in the DMM kit.
“Needle-point” type probes will not stay connected
into the J-44175-A Fuel Composition Tester
connector jacks. Insert the black lead into the
COM or common ground port of the DMM. Insert
the red lead into the VOLT-OHM port of the DMM
(see figure 3).
-
Figure 3

7
Remove the J-44175-A Fuel Composition Tester
from it’s storage case and set it on a stable level
surface, such as a work bench.
Insert the black DMM test lead probe into the
negative “-” jack at the end of the Fuel Composition
Tester’s handle. Then insert the red DMM test lead
probe into the positive “+” jack at the end of the
tester’s handle (see figure 4). Make sure the DMM
test probes remain in full contact with the jacks in
the tester’s handle. “Needle-point” insulation-
piercing type probes will not stay connected into
the tester connector jacks.
Activate the J-39200 DMM by turning the dial
to Volts-AC (V~). Then activate the frequency
measurement feature by pressing the button
marked “Hz”. The Fuel Tester’s output signal is to
be read as an “AC Frequency.”
The next step is to activate the Fuel Composition
Tester by pressing it’s Power button. The green
fuel diagnostic LED should light up and remain lit
when the tester is powered up. If the green LED
is not lit when the tester is powered up with no
fuel sample in it, or if the yellow LED is lit, please
refer to the Troubleshooting section of this manual.
Notice: The tester will automatically shut off
after 10 minutes to extend battery life. If more
time is needed to complete testing, push the
Power button to turn the tester on again.
Test Lead
Connection
to tester
Tip Jack
Figure 4

8
Perform a verification test of the J-44175-A Fuel Composition Tester.
Observe the “air frequency” and the “acetone frequency.”
NOTE: Pure acetone is required for this test.
Use only pure acetone from containers that have been kept closed. Pure acetone
can be purchased at hardware or paint stores. Most body repair shops use acetone.
Setup
Make sure the tester is clean and dry. Do NOT use compressed air to dry
the tester as “shop air” can contain water. Fingerprints, sweat, water,
moisture or any other debris in the fuel bowl can make the tester read
inaccurately.
1. Push the power button to turn the tester on.
2. Connect a DMM to the tester “+” and “–” terminals. Insert the
DMM test probes securely into the tester’s tip jacks at the base of the
tester handle. Make sure the test probes remain securely connected.
Needle-point insulation-piercing probes will not stay connected.
3. Set the DMM to AC Hz (frequency) scale and take a reading.
_ _
Step 1 AIR FREQUENCY TEST
1. No fuel sample (air only) in the test cell.
2. Is the DMM frequency reading between 35 Hz and 48 Hz?
YES
Go to
Step 2
NO
Go to
Step 4
Step 2 ACETONE FREQUENCY TEST
1. Fill the test cell with pure acetone. See NOTE above about acetone.
2. Is the DMM frequency reading between 130 Hz and 142 Hz?
YES
Go to
Step 2
NO
Go to
Step 4
Step 3
Tester is verified. Drain the tester.
Make sure the tester is clean and dry. Do NOT use compressed air to
dry the tester as “shop air” can contain water. Fingerprints, sweat,
water, moisture or any other debris in the fuel bowl can make the
tester read inaccurately.
Step 4 Replace the 9-volt battery and retest, starting at Step 1. If the results are
still outside the specified limits, the tester will need tobe sent out for
repair. See “REPAIR” in last pages of this manual.
TESTER VERIFICATION
Use the procedure listed below.
When the tester is verified to be
operating properly, the user is now
ready to perform the diagnostic
procedures.
Figure 5

9
Converting Digital MultiMeter frequency
readings to ethanol percentage
To convert the frequency output of the tester into
ethanol percentage, subtract 50 from the AC
frequency displayed on the Digital Multi Meter. The
result will be ethanol percentage. See examples
listed below.
ETHANOL BLENDED FUEL (E85)
DIAGNOSTIC PROCEDURE
The term “blended fuel” used in this manual refers
to an alternative fuel ethanol/gasoline mixture
called E85. This fuel has also been called Flexible
Fuel or Alternative Fuel-Ethanol. The ethanol
percentage of E85 is much higher than the
maximum allowable10% ethanol often found in
“normal” gasoline. Fuel stations that sell this type
of fuel have dispensing pumps that are clearly
marked E85, meaning a mixture of up to 85%
ethanol with the remainder of the mixture being
gasoline. The actual ethanol percentage varies
according to seasonal requirements.
When using the J-44175-A fuel Composition Tester,
measured ethanol values between 60% and 91%
(the tester’s AC frequency signal between 110 Hz
and 141 Hz) are acceptable for E85. Measured
ethanol limits are slightly larger than ASTM
specifications due to the combination of equipment
DIAGNOSTIC PROCEDURES
AC frequency Hz displayed on DMM Subtract 50 Ethanol Percentage
“Air frequency” Should be between 35 Hz and 48 Hz — —
Fuel example A 50 Hz – 50 0% Ethanol
Fuel example B 58 Hz – 50 8% Ethanol
Fuel example C 135 Hz – 50 85% Ethanol
“Acetone frequency” Should be between 130 Hz and 142 Hz — —
Figure 6

10
tolerance, the effect of ambient humidity and
temperature on measurement accuracy, and
seasonal changes in ethanol content.
IMPORTANT: E85 fuel can absorb small amounts
of water - even from humidity in the air - which
can affect the tester's measurement of the ethanol
percentage. Minimize the time that a fuel sample
is exposed to the atmosphere before it is tested
for ethanol percentage. If the fuel sample obtained
from the fuel rail is not tested for ethanol percentage
within 15 seconds, discard that sample and obtain
a fresh sample. Any amount of water/moisture in
the fuel mixture will change the chemical properties
of the mixture. The accuracy of the J-44175-A
Fuel Composition Tester can be affected by any
form of moisture that can be held in suspension
by the ethanol.
Tester Set-Up and Verification
Follow the instructions in the tester set-up and
tester verification section in the front of this manual
before obtaining the fuel samples.
Fuel Quality - Water
Water contamination in the fuel system may cause
driveability conditions such as hesitation, stalling,
no start, or misfires in one or more cylinders.
Water may collect at the bottom of the fuel tank,
near a fuel injector, or at the lowest point in the
fuel rail and cause a misfire in that cylinder.
Large amounts of water will separate from the fuel
if a fuel sample is allowed to settle for a few
minutes. If the fuel system is contaminated with water,
inspect the fuel system components for rust or
deterioration.

11
Fuel Quality - Sediment
Sediment will be visible in a “settled” fuel sample.
Sediment may collect at the bottom of the fuel tank,
near a single fuel injector, or at the lowest point in
the fuel rail and cause a misfire in that cylinder.
If sediment is present it will generally be located
in the bottom of the fuel tank. It is possible that
sediment can also accumulate in the fuel rail.
Sediment from the fuel will collect at the bottom
of the beaker if a fuel sample is allowed to settle
for a few minutes.
Fuel Quality - Excessive Ethanol
Excessive concentrations of ethanol may cause
driveability conditions. For E85, ethanol percentage
is normally between 70% and 85%. Some states
that have extremely cold winter temperatures
allow as low as 60% during the winter. When
using the J-44175-A fuel composition tester,
measured ethanol values between 60% and 91%
(the tester’s AC frequency signal between 110 Hz
and 141 Hz) are acceptable for E85. Measured ethanol
limits are slightly larger than ASTM specifications
due to the combination of equipment tolerance,
the effect of ambient humidity and temperature on
measurement accuracy, and seasonal changes in
ethanol content.
IMPORTANT: The accuracy and reliability of this
entire procedure depends on preventing the fuel
sample or the tester’s fuel sampling cell from
becoming contaminated.
Clean the 100mL beaker with a clean, dry paper
towel before taking a fuel sample. DO NOT USE
compressed “shop air” to blow out the beaker.
Compressed shop air often contains water or solid
contaminants. Contaminants of ethanol-blended
fuels include water, methanol, and salts. Be careful
not to allow fingerprints, sweat, water or any other

12
outside debris to contaminate the fuel sample, beaker,
tester or fuel gage as this will cause an error in the
test result, leading to a misdiagnosis.
TWO fuel samples are to be taken, with different
tests on each sample. Fill the 100mL beaker to
the 100mL mark on the beaker for each sample.
Turn ignition off. Remove gas cap. Connect
either the J-34730-FF orange-face pressure
gage or the CH-48027 Digital Pressure Gage to
the fuel rail pressure connection. Use a shop
towel around the fitting to avoid fuel spillage.
If fuel system components are to be serviced,
relieve the fuel system pressure before servicing
the fuel system components to reduce the risk
of fire and personal injury.
After relieving the system pressure, a small amount
of fuel may be released when servicing the fuel
lines or connections. In order to reduce the chance
of personal injury, cover any fuel line fittings with
a shop towel before disconnecting. This will catch
any fuel that may leak out. Place the towel in an
approved container when the disconnection is
complete.
Gasoline and gasoline vapors are highly
flammable. To avoid risk of personal injury
perform test away from open flames, sparks
and any other potential sources of ignition.
In order to reduce the risk of fire and
personal injury use extreme caution when
connecting and disconnecting gage to
fuel rail.
Figure 7
Alcohol-resistant
gauge/hose/fittings
assembly
CH-48027

13
Obtaining the TWO fuel samples
Each fuel sample will be taken at different times.
Each fuel sample will be tested differently.
Flush out the gage hose with the test vehicle’s fuel
before taking any fuel samples used for testing.
1. Connect the fuel pressure gage to the
fuel rail.
2. Insert the gage’s bleed hose into an approved
container.Do not use the 100mL beaker for
this flushing procedure.
3. Turn the ignition switch to the ON position. DO
NOT START THE ENGINE.
4. Command the fuel pump ON with the scan tool.
5. Slowly open the bleed valve on the fuel pressure
gage, until the gage hose has been flushed.
The FIRST fuel sample is used to test
for water or sediment in the fuel.
The first fuel sample is not to be used in the
J-44175-A tester. After the first fuel sample is
tested for water or sediment, that sample is to be
discarded. Fuel should be disposed of in accordance
with all applicable federal, state and local
requirements.
The SECOND fuel sample is to be used
in the J-44175-A tester.
Use either the J-34730-FF orange-face
pressure gage or the CH-48027 Digital

14
Pressure Gage to obtain the samples (see
figure 7). Either gage is ethanol tolerant.
NOTE: Flush out the gage hoses with the test
vehicle’s fuel prior to taking any fuel samples.
Follow the instructions included with either
pressure gage.
To obtain a fuel sample from the pressure gage
bleed hose, use the 100mL beaker that is included
with the fuel tester kit (see figure 8).
IMPORTANT: Water or moisture can adversely
effect test results. Make sure the100mL beaker is
clean and dry before obtaining a fuel sample. DO
NOT USE compressed “shop air” to blow out the
beaker. Compressed shop air often contains water
or solid contaminants.
Testing the first fuel sample
Water and Sediment Test
1. Close the bleed valve on the fuel pressure gage.
2. Connect a scan tool and locate it under wood,
where the 100mL beaker and pressure gage
will be used.
3. Turn the ignition switch to the ON position. DO
NOT START THE ENGINE.
4. Place the bleed hose from the pressure gage
into the 100mL beaker.
5. Command the fuel pump ON with the scan tool.
6. Slowly open the bleed valve on the fuel
pressure gage, until the 100mL beaker is full
to the 100mL mark. Shut the bleed value.
Beaker
Bleed Hose
Sample
Figure 8

15
NOTE: The first fuel sample is NOT to be used in
the J-44175-A tester. If this is the second fuel
sample, it is to be used for the Excessive Ethanol
Test. Continue to the Excessive Ethanol Test.
7. Place the 100mL beaker on a workbench, and
allow the first fuel sample to sit unmoved for
five minutes.
8. After five minutes, look through the fuel in the
beaker. If water or sediment appears in the fuel
sample, clean the fuel system and replace the
fuel in the vehicle. Fuel should be disposed of in
accordance with all applicable federal, state
and local requirements.
9. If step 8 is complete and no obvious water or
sediment is visible, discard the first fuel
sample in accordance with all applicable
federal, state and local requirements, then
continue to the Excessive Ethanol Test.
Testing the second fuel sample
Ethanol blended fuel (E85)
Excessive Ethanol Test
Obtain the second fuel sample.
Follow steps 1 - 6 on page 14.
IMPORTANT: Do not delay in testing the second
E85 fuel sample. E85 fuel can absorb small
amounts of water - even from humidity in the air -
which can affect the tester’s measurement of the
ethanol percentage. Minimize the time that a fuel
sample is exposed to the atmosphere before it is
tested for ethanol percentage. Read the frequency
within 15 seconds of placing the second fuel
sample into the tester.(The frequency may slowly
change during the test.) If the second fuel sample
obtained from the fuel rail is not tested for ethanol
percentage within 15 seconds, discard that sample

16
and obtain a fresh sample. Any amount of water/
moisture in the fuel mixture will change the
chemical properties of the mixture. The accuracy
of the J-44175-A Fuel Composition Tester can be
affected by any form of moisture that can be held
in suspension by the ethanol.
A portion of the second fuel sample is poured
from the beaker into the tester’s fuel test ports.
The tester’s funnel/bowl does not have to be
completely filled to perform an accurate test.
Twenty (20) milliliters of fuel is sufficient to
perform this test. (see figure 9). The fuel can enter
the test cell through either of the two fuel test
ports. A good indication that you have enough fuel
in the tester is when the fuel is at least at the top
of each fuel test port.
If the Red Fuel Diagnostic LED is illuminated,
or the frequency measurement is above 160 Hz,
refer to “J-44175-A frequency measures above
160 Hz, and/or the red LED is on” in the appendix.
If the Green Fuel Diagnostic LED is illuminated,
please refer to the AC Frequency Hz reading on
the DMM. If the frequency measurement is above
160 Hz, refer to “J-44175-A frequency measures
above 160 Hz, and/or the red LED is on” in the
appendix.
If the ethanol blended “E85” fuel sample
measures more than 91% ethanol (higher than
141 Hz), add fresh, regular gasoline to the
vehicle’sfuel tank to reduce the total ethanol
percentage to 85% or less. If retesting still shows
the ethanol percentage to be above 85% (higher
than 135 Hz), continue adding fresh, regular
gasoline until the ethanol content is 85% or
less. If the fuel tank is full and regular gasoline
needs to be added, some fuel will have to be
drained from the tank.
Figure 9

17
Follow the appropriate General Motors
Diagnostic Service Procedure
It is very important that the proper General Motors
Service Procedure be followed to produce reliable
test results. Depending on the circumstances, the
user may need to reference one or more of the
following procedures:
- Fuel Composition Diagnosis
- Alcohol/Contaminants-in-Fuel Diagnosis
- Fuel System Cleaning
- Fuel Composition Sensor Test
- P0169 - Incorrect Fuel Composition
- P0178 - Fuel Composition Sensor Circuit
Low Frequency
- P0179 - Fuel Composition Sensor Circuit
High Frequency
End of Test Procedure
When the test is complete, disconnect the DMM
from the Fuel Composition Tester by removing the
DMM test leads from the tip jacks at the base of
the tester handle. The fuel sample can be discarded
by picking up the tester by the handle and pouring
the sample out of one side of the funnel (see
figure 10). Fuel should be disposed of in accordance
with all applicable federal, state and local
requirements.
In order to prevent contamination of the sensing
cell it is recommended that the tester be allowed
to air dry with the tester upside-down for at least
five minutes. DO NOT USE compressed “shop air”
to blow out the tester.Compressed shop air often
contains water or solid contaminants that could
leave the tester’s sensing cell “dirty”. Simply turn
the tester upside down on a flat surface, such as
a metal workbench. The tester has been designed
to allow fluid to exit the tester in this position, and
Figure 10

18
ambient air is sufficient to dry it. The handle and
outside surfaces of the tester can be cleaned with
a damp cloth.
Important: Do not allow any substances other
than gasoline, ethanol/gasoline blends, air or
acetone into the test ports of the tester. Pure
acetone can be used to clean the tester’s sensing
cell, if needed. Do not use any cleaners or solvents
other than pure acetone to clean the internal portion
of the test ports. The chemicals in those other liquids
could contaminate the sensing cell and cause a
misdiagnosis.
Once the unit has been air dried, return the tester
to the storage case and store in a cool, dry place.
NON-BLENDED FUEL
DIAGNOSTIC PROCEDURE
The term “non-blended fuel” used in this manual
refers to “normal” gasoline found at all fuel stations.
This fuel may be dispensed from pumps with signs
indicating “This fuel may contain up to 10% ethanol.”
Some fuel companies add up to 10% ethanol as
an octane improver, or as an oxygenate to reduce
exhaust emissions. The 10% level is the maximum
allowable by the Environmental Protection Agency
(EPA). Ethanol concentrations of greater than
10%can cause driveability conditions and fuel
system deterioration. Excessive concentrations of
ethanol, used in vehicles not designed for it, may
cause driveability conditions. These include
hesitation, lack of power, stalling, fuel system
corrosion, deterioration of rubber components, fuel
filter restrictions, and no start.

19
When using the J-44175-A tester, it is acceptable
for non-blended “normal” gasoline to measure
between 0% and 15% ethanol percentage (between
50 Hz and 65H z).
Tester Set-Up and verification
Follow the instructions in the tester set-up and
tester verification section in the front of this manual
before obtaining the fuel sample.
Fuel Quality - Water
Water contamination in the fuel system may cause
driveability conditions such as hesitation, stalling,
no start, or misfires in one or more cylinders. Water
may collect at the bottom of the fuel tank, near a
single fuel injector, or at the lowest point in the fuel
rail and cause a misfire in that cylinder.
It is possible for small amounts of water to be
absorbed by the ethanol found in normal gasoline/
ethanol fuel mixtures. However, it does change the
chemical properties of the mixture. The accuracy
of the J-44175-A Fuel Composition Tester can be
affected by small amounts of water that can be
held in suspension by the ethanol.
Large amounts of water will separate from the
fuel if a fuel sample is allowed to settle for a few
minutes. If the fuel system is contaminated with
water, inspect the fuel system components for rust
or deterioration.
Fuel Quality - Sediment
Sediment will be visible in a “settled” fuel sample.
Sediment may collect at the bottom of the fuel tank,
near a single fuel injector, or at the lowest point in
the fuel rail and cause a misfire in that cylinder.

20
If sediment is present it will generally be located
in the bottom of the fuel tank. It is possible that
sediment can also accumulate in the fuel rail.
Sediment from the fuel will collect at the bottom
of the beaker if a fuel sample is allowed to settle
for a few minutes.
Fuel Quality - Excessive Ethanol
Excessive concentrations of ethanol may cause
driveability conditions. According to EPA guidelines,
non-blended normal gasoline may contain up to
10% ethanol. It is acceptable for the J-44175-A
tester to indicate up to 15% ethanol (65 Hz) for
non-blended normalgasoline.
IMPORTANT: The accuracy and reliability of this
entire procedure depends on preventing the fuel
sample or the tester’s fuel sampling cell from
becoming contaminated.
Clean the 100mL beaker with a clean, dry paper
towel before taking a fuel sample. DO NOT USE
compressed “shop air” to blow out the beaker.
Compressed shop air often contains water or solid
contaminants. Contaminants of ethanol -blended
fuels include water, methanol, and salts. Be careful
not to allow fingerprints, sweat, water or any other
outside debris to contaminate the fuel sample,
beaker,tester or fuel gage as this will cause an
error in the test result, leading to a misdiagnosis.
TWO fuel samples are to be taken, with different
tests on each sample. Fill the100mL beaker to the
100mL mark on the beaker for each sample.

21
Turn ignition off. Remove gas cap. Connect either
the J-34730-FF orange-face pressure gage or the
CH-48027 Digital Pressure Gage to the fuel rail
pressure connection. Use a shop towel around the
fitting to avoid fuel spillage.
If fuel system components are to be serviced, relieve
the fuel system pressure before servicing the fuel
system components to reduce the risk of fire and
personal injury.
After relieving the system pressure, a small amount
of fuel may be released when servicing the fuel
lines or connections. In order to reduce the chance
of personal injury, cover any fuel line fittings with
a shop towel before disconnecting. This will catch any
fuel that may leak out. Place the towel in an approved
container when the disconnection is complete.
Obtaining the TWO fuel samples
Each fuel sample will be taken at different
times. Each fuel sample will be tested
differently.
Gasoline and gasoline vapors are highly
flammable. To avoid risk of personal injury
perform test away from open flames, sparks
and any other potential sources of ignition.
In order to reduce the risk of fire and
personal injury use extreme caution when
connecting and disconnecting gage to
fuel rail.

22
Flush out the gage hose with the test vehicle’s
fuel before taking any fuel samples used for
testing.
1. Connect the fuel pressure gage to the
fuel rail.
2. Insert the gage’s bleed hose into an approved
container. Do not use the 100mL beaker for
this flushing procedure.
3. Turn the ignition switch to the ON position. DO
NOT START THE ENGINE.
4. Command the fuel pump ON with the
scan tool.
5. Slowly open the bleed valve on the fuel
pressure gage, until the gage hose has
been flushed.
The FIRST fuel sample is used to test for water
or sediment in the fuel.
The first fuel sample is not to be used in the
J-44175-A tester. After the first fuel sample is
tested for water or sediment, that sample is to
be discarded. Fuel should be disposed of in
accordance with all applicable federal, state
and local requirements.
The SECOND fuel sample is to be used
in the J-44175-A tester
Use either the J-34730-FF orange-face pressure
gage or the CH-48027 Digital Pressure Gage to
obtain the samples (see figure 11). Either gages
is ethanol tolerant.
NOTE: Flush out the gage hoses with the test
vehicle’s fuel prior to taking any fuel samples. Follow
the instructions included with either pressure gage.
To obtain a fuel sample from the pressure gage bleed
hose, use the 100mL beaker that is included with
the fuel tester kit (see figure 12).
Figure 11
Alcohol-resistant
gauge/hose/fittings
assembly
CH-48027