Actron Professional Fuel Pressure Tester Kit CP7838 - Manual (Page 6)

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 test 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.
English
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.
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 pressure regulator
• Restriction in return line
• Faulty fuel line couplings at fuel tank
• Sticking or “Sluggish” Fuel Injectors
Possible causes of low fuel pressure readings
are the following:
• Clogged or restricted fuel filter
• Restriction in pressure line
• Faulty fuel pump
• Faulty fuel pump relay
• Blown fuel pump fuse
• Faulty fuel pump wiring
• Clogged or restricted fuel pump filter
• Faulty fuel pressure regulator
• Leaking fuel injectors
• Faulty fuel line couplings at fuel tank.
Care and Maintenance
Apply a lightweight household oil to the rubber “O” rings inside adapters before each use.