Advertisement
``
Pressure should remain stable through entire period of acceleration.
7.2.3.
If gauge readings are correct, disconnect inertia switch. Crank engine for 15 seconds to reduce fuel pressure. Remove gauge and in-
line adaptor. Install original fuel line and connect intertia switch. Start engine and check for fuel leaks.
8. FUEL PRESSURE TEST
CHRYSLER (TYPICAL)
CAUTION: High fuel pressure may be present in fuel lines and component parts. Relieve pressure before attempting to open
system for testing or component replacement. DO NOT allow fuel to run onto engine or electrical parts while testing fuel
system components.
8.1.
FUEL PRESSURE RELEASE
8.1.1.
Fuel Pressure must be fully released before opening fuel system or removing any fuel carrying components. To release pressure in
tank, open fuel tank cap slowly.
8.1.2.
To release remaining pressure in system, disconnect fuel pump connector (electrical) in boot and crank engine.
8.2.
TBI FUEL PUMP TEST
8.2.1.
Release fuel pressure. Disconnect 5/16" fuel supply hose. Connect fuel system pressure Gauge between fuel supply hose and engine
fuel line.
8.2.2.
Turn ignition on. Activate fuel pump. If fuel pump pressure is at specification, fuel system is functioning properly.
8.2.3.
If fuel pressure is not to specification, record pressure. Install fuel pressure gauge in fuel supply line at rear of vehicle between fuel
tank and fuel filter.
8.2.4.
Activate fuel pump. Record pressure reading. If fuel pressure is 5 psi higher than the first pressure reading, replace fuel filter.
8.2.5.
If no change in pressure reading is observed, gently squeeze fuel return hose. If fuel pressure increases, replace fuel pressure
regulator. If no change in fuel pressure is observed, problem is plugged fuel pump filter sock or defective fuel pump.
8.2.6.
If fuel pressure is more than specification, remove fuel return hose at rear of vehicle. Connect an extension hose to return hose. Place
8.2.7.
hose in an approved container with at least a 2 gallon capacity.
8.2.8.
Activate fuel pump. If fuel pressure is now within specification, check in-tank return fuel hose for kinking. Replace fuel tank assembly if
8.2.9.
in-tank reservoir check valve or aspirator jet is plugged.
8.2.10.
If fuel pressure is still more than specification, remove fuel return hose from throttle body. Connect a substitute hose to throttle body
return nipple. Place other end of hose in an approved container.
8.2.11.
Activate fuel pump. If fuel pressure is at specification, check for a restricted fuel return line between throttle body and fuel tank. If no
change was observed, replace fuel pressure regulator.
NOTE: Perform fuel pump test with fuel tank at least half full. Before disconnecting a fuel line during testing, repeat fuel pressure release
procedure.
8.3.
PFI FUEL PUMP TEST
8.3.1.
Release fuel pressure. Remove cap from service valve on fuel rail. Connect fuel system pressure Gauge to service valve.
8.3.2.
Turn ignition on. Activate fuel pump. If fuel pump pressure is at specification, fuel system is functioning properly.
8.3.3.
If fuel pressure is not to specification, record pressure and remove gauge. Activate pump. Ensure no fuel leaks from service valve.
Install cap on service valve.
8.3.4.
If fuel pressure is not to specification, install pressure gauge in fuel supply line between fuel tank and fuel filter at rear of vehicle.
Activate fuel pump.
8.3.5.
Record pressure reading. If fuel pressure is 5 psi higher than the first pressure reading, replace fuel filter. If no change in pressure
reading is observed, gently squeeze fuel return hose.
8.3.6.
If fuel pressure increases, replace fuel pressure regulator. If no change in fuel pressure is observed, problem is plugged fuel pump
filter sock or defective fuel pump.
8.3.7.
If fuel pressure is more than specification, remove fuel return hose at rear of vehicle. Connect an extension hose to return hose. Place
hose in an approved container with at least a 2 gallon capacity.
8.3.8.
Activate fuel pump. If fuel pressure is now within specification, check in-tank return fuel hose for kinking. Replace fuel tank assembly if
8.3.9.
in-tank reservoir check valve or aspirator jet is plugged.
8.3.10.
If fuel pressure is still more than specification, remove fuel return hose from pressure regulator. Connect a substitute hose to fuel
pressure regulator. Place other end of hose in an approved container.
8.3.11.
Activate fuel pump. If fuel pressure is at specification, check for a restricted fuel line. If no change was observed, replace fuel pressure
regulator.
NOTE: Perform fuel pump test with fuel tank at least half full. Before disconnecting a fuel line during testing, repeat fuel pressure release
procedure.
9. FUEL PRESSURE TEST
HONDA / ACURA(TYPICAL)
CAUTION: High fuel pressure may be present in fuel lines and component parts. Relieve pressure before attempting to open
system for testing or component replacement. DO NOT allow fuel to run onto engine or electrical parts, or allow an open
flame in area while testing fuel system components.
Basic diagnosis of fuel system should begin with determining fuel system pressure. If fuel pump fails to run, inspect power supply to
main relay. If all power supplies are present (i.e. battery, ignition and starter switch during cranking), perform functional test of main
relay.
9.1.
RELIEVING FUEL PRESSURE
9.1.1.
Remove negative battery cable.
9.1.2.
Loosen fuel tank filler cap.
9.1.3.
Place clean shop rag around fuel filter.
9.1.4.
Slowly loosen 6mm service bolt on top of fuel filter (one complete turn) to relieve system pressure.
9.1.5.
Always replace washer under 6mm bolt after loosening.
9.2.
PRESSURE TESTING
9.2.1.
After relieving fuel pressure connect Fuel Pressure Gauge at 6mm service bolt location. Reconnect negative battery cable. Start
engine and note pressure. If vehicle will not start, has spark, and no fuel pressure is evident, inspect fuel pump main relay.
9.2.2
Disconnect vacuum hose from pressure regulator and inspect for manifold vacuum. If vacuum is not present, check for restriction in
vacuum port or hose.
© Jack Sealey Limited
Original Language Version
VSE210 Issue 2 (HF)
08/09/21
Advertisement
