7
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.
