OEM 27167 Service manual

UNPACKING
After unpacking the unit, inspect carefully
for any damage that may have occurred
during transit. Check for loose, missing, or
damaged parts. If any damage is observed, a
shipping damage claim must be filed with the
carrier. DO NOT use the OEM®27167 Fuel
Pressure Test Kit if broken, bent, cracked or
damaged parts (including labels) are noted.
Any Test Kit that appears damaged in any
way, operates abnormally or is missing parts
should be removed from service immediately.
If you suspect that the Test Kit was subjected
to shock load (a load that was dropped
suddenly, unexpectedly, etc.), immediately
discontinue use until it has been checked by
a factory authorized service center.
Please read and save these instructions. Read through this owner’s manual carefully before using product. Protect yourself and
others by observing all safety information, warnings, and cautions. Failure to comply with instructions could result in personal
injury and/or damage to product or property. Please retain instructions for future reference.
Operating Instructions and Parts Manual 27167
FUEL PRESSURE
TEST KIT
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10/18
2018 OEM®
NOTE: Before you begin, you will need fuel system specifications for your specific vehicle. Vehicle specific shop
manuals are the most reliable source for the information.
SAFETY
CAUTION: Before using this tool or any of its
accessories, read this manual and follow all Safety Rules
and Operating Instructions.
To prevent accidents that could result in serious injury
and/or damage to vehicle or test equipment, carefully
follow safety rules and test procedures at all times when
working on vehicles.
• Always wear approved eye protection.
• NEVER use Fuel Pressure Tester Kit on Diesel or Flex
Fuel engines!
• Always operate vehicle in a well-ventilated area.
• DO NOT inhale exhaust gases or fuel vapors.
• Only use Fuel Pressure Tester Kit for measuring fuel
pressure.
• NEVER attach or remove Fuel Pressure Tester Kit from
fuel rail test port with ignition key on.
• Always place end of 6 Ft. bleed-off hose in an approved
container for fuel during testing and when bleeding off
fuel pressure.
• NEVER smoke or have open flames near vehicle. Vapors
from fuel and charging battery are highly flammable and
explosive.
• NEVER permit fuel to spill on hot engine parts. If a spill or
leak occurs, immediately turn ignition key off and clean
up fuel.
• NEVER leave vehicle unattended while running tests.
• Always keep yourself, tools and test equipment away
from all moving or hot engine parts.
• Always make sure vehicle is in PARK (Automatic
transmission) or NEUTRAL (manual transmission) and
parking brake is set. Block drive wheels.
• NEVER lay tools on vehicle battery. Terminals may short
together causing harm to yourself, tools or battery.
• Always keep a fire extinguisher suitable for fuel/electrical/
chemical fires handy.
• Always use extreme caution when working around
ignition coil, distributor cap, ignition wires and spark
plugs. These components contain High Voltage when
engine is running.
• Complete all Pre-Testing Checks before beginning fuel
pressure testing.
• Always follow vehicle manufacturer’s warnings, cautions
and service procedures.
WARNING: Cancer and Reproductive Harm. For more
information, go to www.P65Warnings.ca.gov.

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Operating Instructions and Parts Manual 27167
10/18
2018 OEM®
FUEL PRESSURE
TEST KIT
FUEL PRESSURE TESTER COMPONENTS
1. Rubber Boot: Boot is used to protect gauge and
maintain appearance.
2. Dial Face: Contains measurement scales that show
amount of fuel pressure present in fuel system.
3. Pressure Relief Button: Used to relieve fuel pressure in
gauge hose before disconnecting gauge hose from fuel
rail.
4. Bleed-Off Hose: A 6 Ft. hose that bleeds off fuel
pressure when pressure relief button is pressed. Never
use a bleed-off hose shorter than 6 Ft.
Important: Always make sure end of bleed-off hose is in
an approved container for fuel at all times during testing
and when bleeding off fuel pressure!!
5. Gauge Hose: Hose that carries fuel to the gauge, so
that pressure can be measured.
6. Chrysler/GM Test Port Adapter: Adapter is used to
connect gauge hose to GM, Chrysler and other vehicles
equipped with a Schrader valve test port on fuel rail.
7. Ford Test Port Adapter: Adapter is used to connect
gauge hose to Ford vehicles equipped with a Schrader
valve test port on fuel rail.
8. GM TBI Test Adapter: Adapter is used to connect
gauge hose to GM TBI vehicles NOT equipped with a
Schrader valve test port.
9. M12 X 1.25 Banjo Bolt Adapter: Adapter is used to
connect gauge hose to Asian, European and select
domestic vehicles equipped with fuel Banjo Bolt
Connections.
10. Dual Manifold Test Adapter: Adapter is used to
connect gauge hose to vehicles with rubber hose
connections on the fuel rail, fuel line or fuel filter.
FUEL INJECTION SYSTEM THEORY
There are two basic types of fuel injection systems cur-
rently being used. The first type is called “port” or “multi-
port” fuel injection. In this system, fuel injectors spray fuel
directly into intake manifold behind intake valve. These
systems typically have one fuel injector per cylinder. The
second type is commonly called Throttle Body Injection
(TBI) for GM and Chrysler vehicles or Central Fuel Injec-
tion (CFI) for Ford vehicles. These systems use one or two
fuel injectors mounted on top of intake manifold. They
spray fuel into throttle body similarly to a conventional
carburetor.

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Operating Instructions and Parts Manual 27167
10/18
2018 OEM®
FUEL PRESSURE
TEST KIT
10/18
2018 OEM®
FUEL SYSTEM COMPONENTS
It is a good idea to understand how the fuel system
components work and how they relate to one another
before doing any fuel pressure testing. The fuel pump
pumps fuel from the fuel tank to the fuel pressure regulator
and fuel injectors. The fuel pressure regulator divides fuel
between the pressure line and return line. The fuel in the
pressure line goes to fuel injectors, while fuel is returned to
fuel tank through the return line.
Fuel Tank: A large container that holds vehicle’s supply of
fuel.
Fuel Pump: An electric motor that pumps fuel into the fuel
system at a constant pressure. It is mounted in the fuel
tank or on the frame. Some vehicles have more than one
fuel pump.
Fuel Pump Filter: A filter that is usually located in fuel
tank. Its function is to prevent foreign particles from
reaching the fuel pump. A clogged or restricted fuel pump
filter can cause low fuel pressure readings. When replacing
a fuel pump it is a good idea to replace the fuel pump filter.
Return Line: Path way for excess fuel to return to the fuel
tank.
Pressure Line: A pressurized fuel line that carries fuel from
the fuel tank to the fuel injectors.
Fuel Filter: A filter that is located in-line with the pressure
line. Its function is to prevent foreign particles from
reaching the fuel injectors. A clogged or restricted fuel filter
can also cause low fuel pressure readings. This is the only
fuel system component that requires periodic replacement.
Refer to vehicle owner’s manual for replacement interval.
Fuel Rail Test Port: A Schrader valve located on the
fuel rail that allows easy connection of a fuel pressure
gauge to measure fuel pressure. Do not confuse this valve
with the Schrader valves that are used for recharging air
conditioning systems.
Fuel Pressure Regulator: The fuel pressure regulator
is connected across the pressure line and return line. It
contains a spring-loaded valve assembly that opens to
allow fuel to move into the return line, when the pressure
line fuel pressure is exceeded. It is used to keep a
constant fuel pressure drop across the fuel injectors.
Some fuel pressure regulators have a vacuum port so fuel
pressure can be adjusted based on engine load. These
are commonly called vacuum actuated (compensated)
fuel pressure regulators. A leaking fuel pressure regulator
can cause low fuel pressure readings and hard starting
problems.
Fuel Rail: The fuel rail assembly is bolted to the intake
manifold. Its purpose is to hold the fuel injectors in place
and to deliver pressurized fuel to the fuel injectors.
Fuel Injectors: A precision valve that is controlled by a
solenoid. Fuel injection is controlled by the amount of fuel
pressure, and the size and duration of the valve opening.
Fuel injectors contain a filter used to prevent very small
particles from clogging the valve. Leaking fuel injectors will
cause fuel pressure to slowly decrease when the ignition
key is on and engine is off.

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Operating Instructions and Parts Manual 27167
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2018 OEM®
FUEL PRESSURE
TEST KIT
PRE-TEST CHECKS
1. Read Safety Precautions.
2. Do a thorough visual and “hands-on” inspection of the
engine and fuel system. Look for loose or cracked
electrical wiring, battery cables, ignition wires and fuel
or vacuum lines.
3. Verify that the fuel tank has an adequate supply of fuel
and the battery is fully charged.
4. Verify that the inertia switch on certain Ford/Lincoln/
Mercury vehicles has not been tripped. (The inertia
switch is usually located in the trunk.)
5. Verify that all fuel system fuses are good.
6. Verify that fuel vapor recovery system and gas cap are in
good condition.
7. Verify that manifold vacuum is within manufacturers’
specification. (Typically 18-20 inches at idle)
8. Look for fuel leaks and immediately clean up any spilled
fuel.
9. If engine will not start, check ignition system for spark.
If no ignition spark is present, refer to vehicle service
manual for No Start Diagnostics.
10. Inspect the wire harnesses and electrical connectors
for damaged or corroded parts.
11. Check other electrical systems including ignition and
car computer system.
FUEL PRESSURE TESTING PROCEDURES
This test procedure explains how to make fuel pressure
measurements on vehicles while the ignition key is on and
while engine is at idle. The procedure also explains the
safest way to connect and disconnect fuel pressure tester
kit from vehicles. If fuel pressure readings measured in
this test procedure are not within vehicles manufacturer’s
specification, then use vehicle service manual along
with fuel pressure tester kit to service problem. This
test procedure does not contain any vehicle specific
diagnostics.
1. Read all Safety Precautions and Pretesting Checks.
2. Apply a lightweight household oil to rubber “0” rings or
test adapters.
3. Turn Ignition Key OFF.
4. Install Gauge.
FOR CHRYSLER/GM VEHICLES WITH TEST
PORT:
• Remove Test Cap.
• Screw Chrysler/GM test port adapter to fuel rail test port
until finger tight.
NOTE: Always wrap a shop rag around fuel rail test port
when attaching test port adapters. This is a precaution
in case a small amount of fuel leaks out while attaching
adapters.
FOR FORD/LINCOLN/MERCURY VEHICLES
WITH TEST PORT:
• Remove Test Cap.
• Screw Ford test port adapter to fuel rail test port until
finger tight.
• Screw Chrysler/GM test port adapter to Ford test port
adapter until finger tight.
FOR GM TBI VEHICLES WITHOUT A TEST PORT:
• Disable fuel pump(s) and relieve fuel system pressure by
following instructions in vehicle service manual.
WARNING: Some vehicles may have more than one fuel
pump. Failure to deactivate all fuel pumps can result
in spilled fuel, fire, or other hazardous conditions that
could cause vehicle damage personal injury, or death.
• Disconnect the fuel line at location described in vehicle
service manual using shop towels to catch any released
fuel.
• Attach GM TBI test adapter, and then attach fuel line to
adapter. Tighten all fittings finger tight and then tighten
gently 1/2 turn with wrenches.

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Operating Instructions and Parts Manual 27167
10/18
2018 OEM®
FUEL PRESSURE
TEST KIT
10/18
2018 OEM®
• Attach hose and pressure gauge assembly to adapter top
fitting and tighten fitting until finger tight.
FOR IMPORT AND SOME DOMESTIC VEHICLES
WITH A BANJO BOLT CONNECTION:
Note: Included is the most popular banjo bolt with
12 mm x 1.25 thread.
• Relieve fuel system pressure by following instructions in
vehicle service manual.
• Remove the vehicle’s fuel bolt at location described in
service manual. Use shop towels to catch any released
fuel.
• Install banjo bolt test adapter in place of fuel bolt.
Position banjo bolt gaskets on either side of banjo.
Banjo with fuel supply line attached should be
sandwiched between banjo bolt gaskets.
• Tighten banjo bolt test adapter finger tight, then gently
snug with wrench.
• Connect hose and pressure gauge assembly to banjo
bolt test adapter fitting. Tighten gauge hose fitting
finger tight.
FOR IMPORT AND DOMESTIC VEHICLES WITH
RUBBER HOSE CONNECTIONS:
• Relieve fuel system pressure by following instructions in
vehicle service manual.
• Disconnect the vehicle’s rubber fuel line hose at location
described in service manual. Use shop towels to catch
any released fuel. Leave rubber hose attached to fuel
line.
• Install matching size adapter hose and hose clamps on
dual manifold test adapter.
• Connect test adapter hose at location where vehicle’s
fuel line was disconnected.
• Connect vehicle’s fuel line to other side of dual manifold
adapter. Use vehicle’s hose clamps on rubber hose.
• Tighten all hose clamps securely.
• Connect hose and pressure gauge assembly to dual
manifold test fitting. Tighten gauge hose fitting finger
tight.
5. Place end of 6 Ft. bleed-off hose in an approved
container for fuel. Bleed-off hose must remain in
container until testing is complete.
6. Turn all accessories OFF (Radio, AlC, Blower Fan,
Headlights, Windshield Wipers, etc.).
7. Re-activate fuel pump and turn ignition key ON.
Do the following checks:
• Listen for fuel pump. Pump should run for approximately
2 seconds.
• Pressurize fuel system by cycling ignition ON and
OFF every ten seconds until fuel pressure is at
manufacturers’ specifications (see vehicle service
manual).
• Check fuel system for leaks. If leaks are found, turn
ignition key OFF and immediately clean up fuel!
• Read fuel pressure from dial face. Pressure should rise to
manufacturer’s specification and hold steady.
• If fuel pressure is not within manufacturer’s specification,
cycle ignition key 2 or 3 more times. If fuel pressure is
still not within manufacturer’s specifications, service
vehicle according to vehicle service manual, then retest.

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Operating Instructions and Parts Manual 27167
10/18
2018 OEM®
FUEL PRESSURE
TEST KIT
• When key-on-engine-off fuel pressure is within
manufacturers’ specification, proceed to Step 8.
• To safely disconnect Fuel Pressure Test Kit, proceed to
Step 9.
8. Start engine and let idle.
• If vehicles fuel system uses a vacuum actuated
(compensated) fuel pressure regulator then fuel
pressure should drop approximately 3-10 psi,
depending on manifold vacuum.
• If vehicles fuel system uses a fuel pressure regulator
without a vacuum port then fuel pressure should remain
constant during both key-on-engine-off and idle.
• Read fuel pressure from dial face.
• If fuel pressure is not within manufacturer’s specification,
service vehicle according to vehicle service manual.
• When repair is completed and idle fuel pressure is now
within manufacturer’s specification, then proceed to
Step 9.
9. Turn Ignition Key OFF.
10. Verify that 6 Ft. bleed-off hose is still in an approved
container for fuel.
11. Fully DEPRESS and HOLD the pressure relief button
until dial face pointer is resting on stop pin.
12. Shake bleed-off hose to make sure that all fuel went
into approved container.
13. Remove gauge hose.
FOR CHRYSLER/GM VEHICLES WITH TEST PORT:
• Wrap a shop rag around fuel rail test port in case a small
amount of fuel drips out while unscrewing test port
adapters.
• Unscrew Chrysler/GM test port adapter from fuel rail test
port and reinstall the Test Cap.
• Wrap a shop rag around Chrysler/GM test port adapter
so any fuel dripping from gauge hose is absorbed.
• Remove bleed-off hose from approved fuel container and
hold gauge hose over container so any remaining fuel
will drip into container.
FOR FORD/LINCOLN/MERCURY VEHICLES WITH
TEST PORT:
• Wrap a shop rag around fuel rail test port in case a small
amount of fuel drips out while unscrewing test port
adapters.
• Unscrew Chrysler/GM test port adapter from Ford test
port adapter.
• Wrap a shop rag around Chrysler/GM test port adapter
so any fuel dripping from gauge hose is absorbed.
• Remove bleed-off hose from approved fuel container and
hold gauge hose over container so any remaining fuel
will drip into container.
• Unscrew Ford test port adapter from fuel rail test port
and reinstall the Test Cap.
FOR GM TBI VEHICLES WITHOUT A TEST PORT:
• Place shop rag under GM TBI adapter in case a small
amount of fuel drips out while unscrewing.
• Disconnect Gauge Hose and wrap a shop rag around so
any fuel dripping from hose is absorbed.
• Disconnect fuel lines from GM TBI adapter and wrap with
shop rag so any fuel dripping from adapter is absorbed.
• Reconnect fuel lines as described in vehicle service
manual.
FOR IMPORT AND SOME DOMESTIC VEHICLES
WITH A BANJO BOLT CONNECTION:
• Wrap a shop towel around banjo bolt connection while
removing bolt.
• Disconnect hose and pressure gauge assembly from
banjo bolt test adapter.
• Wrap a shop towel around end of gauge hose. Hold end
of gauge hose over approved container to catch any
remaining fuel.
• Loosen banjo bolt adapter and remove adapter and
gaskets.
• Re-install vehicle’s fuel bolt with new gaskets on either
side of banjo. Install fuel bolt finger tight, then wrench-
tighten to specifications given in service manual.
• Check for leaks.
FOR IMPORT AND DOMESTIC VEHICLES WITH
RUBBER HOSE CONNECTIONS:
• Place a shop towel under dual manifold test adapter.
• Disconnect hose and pressure gauge assembly from dual
manifold adapter.
• Wrap a shop towel around end of gauge hose. Hold end
of gauge hose over approved container to catch any
remaining fuel.
• Loosen hose clamp securing vehicle’s rubber fuel line
to dual manifold adapter. Disconnect fuel line from
adapter.
• Loosen hose clamp securing dual manifold adapter hose
to vehicle. Disconnect adapter from vehicle.
• Reconnect vehicle’s rubber fuel line to original location.
• Securely tighten hose clamps on vehicle’s fuel line.
• Check for leaks.

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Operating Instructions and Parts Manual 27167
10/18
2018 OEM®
FUEL PRESSURE
TEST KIT
10/18
2018 OEM®
14. Store shop rags in an approved container so they
cannot cause personal injury or a hazardous situation.
15. Store Fuel Pressure Tester in a well-ventilated area
where it cannot cause personal injury or a hazardous
situation.
GENERAL FUEL PRESSURE DIAGNOSTICS
Fuel pressure checking is an essential part of fuel
injection system troubleshooting. High fuel pressure will
make an engine run rich, while low fuel pressure will make
an engine run lean or not at all.
Fuel pressure readings that are higher than
manufacturer’s specifications are generally caused by a
problem in the fuel return line components. Conversely,
fuel pressure readings that are lower than manufacturer’s
specifications are generally caused by a problem in the
fuel pressure line components.
If fuel pressure readings are not within manufacturer’s
specifications, then refer to a vehicle service manual for
step-by-step diagnostic procedures that will pinpoint the
faulty component for a specific vehicle.
POSSIBLE CAUSES OF HIGH FUEL PRESSURE
READINGS ARE THE FOLLOWING:
• Faulty fuel line couplings at fuel tank
• Faulty fuel pressure regulator
• Sticking or “Sluggish” Fuel Injectors
• Restriction in return line
POSSIBLE CAUSES OF LOW FUEL PRESSURE
READINGS ARE THE FOLLOWING:
• Restriction in pressure line
• Clogged or restricted fuel filter
• Faulty fuel pressure regulator
• Faulty fuel pump
• Faulty fuel pump relay
• Blown fuel pump fuse
• Faulty fuel pump wiring
• Faulty fuel line couplings at fuel tank.
• Leaking fuel injectors
CARE & MAINTENANCE
Apply a lightweight household oil to the rubber “0” rings
inside adapters before each use.