Caprice V6-262 4.3L (1987)
Fuel Pressure: Testing and Inspection
Fuel System Pressure Test
FUEL SYSTEM PRESSURE RELEASE
4 & 8 Cylinder Engines
1.
With engine Off, remove fuel pump fuse from fuse block.
2.
Start engine and allow to run until fuel supply is exhausted.
3.
Crank engine an additional 3 seconds to ensure fuel supply is exhausted.
4.
Install fuel pump fuse.
5.
On 4-112 and 4-121 overhead valve engines, install fuel pressure gauge between throttle body side of fuel filter at the rear of the car. On 4-151
engines, install fuel pressure gauge between TBI unit and steel fuel line. On V8 engines, install fuel gauge between front and rear TBI units steel
fuel line.
6.
Start engine and observe fuel pressure. It should be 9 to 13 psi.
7.
Relieve fuel system pressure. Refer to steps 1 through 3 above.
8.
Remove fuel pressure gauge and reinstall fuel lines.
9.
Start engine and check for fuel leaks.
FUEL SYSTEM PRESSURE TESTING
Before servicing fuel system components, fuel system pressure must be released. To relieve pressure, proceed as follows:
a. Remove fuel pump fuse from fuse block.
b. Run engine until fuel remaining in lines is consumed. When engine shuts down, engage starter for approximately three seconds to relieve any
remaining pressure.
c. With ignition off, replace fuel pump fuse.
1.
Remove air cleaner and plug THERMAC vacuum port on throttle body unit.
2.
Remove fuel line between TBI unit and fuel filter or between front and rear TBI units on ``Crossfire'' injection systems. Use a suitable back-up
wrench to hold flare nut on throttle body when removing line.
3.
Install fuel pressure gauge J-29658 or equivalent, between throttle body and filter or, on ``Crossfire'' systems, between front and rear TBI units.
4.
Check pressure reading with engine running. If fuel pressure is not between 9 and 13 psi, refer to ``Fuel System Diagnosis.''
5.
De-pressurize fuel system, remove pressure gauge and reinstall fuel line.
6.
Start engine and check for fuel leaks.
7.
Remove plug from THERMAC vacuum port and install air cleaner.
1986-88 V6 Engine
1.
Obtain two sections of 3/8 inch steel tubing, each approximately 10 inches long, and double-flare one end of each section.
2.
Install flare nut on each section, then connect each of the two sections of tubing into the ``flare nut to flare nut adapters'' that are included in
J-29658-82 Gage Adapters.
3.
Attach pipe and adapter assemblies to the J-29658 gage.
4.
Raise and support vehicle. This engine has a bleed in the pressure regulator to relieve pressure any time the engine is turned off, but a
small amount of fuel may be released when the fuel line is disconnected. To reduce the risk of personal injury, cover the fuel line with a
shop cloth to collect the fuel, then place cloth in suitable container.
5.
Disconnect front fuel feed hose from fuel pipe on body.
6.
Install a ten inch length of 3/8 inch fuel hose onto fuel feed pipe on body and attach other end of hose onto one of the sections of pipe obtained in
step 1.
7.
Attach front fuel feed hose onto other end of tubing.
8.
Start engine and check for leaks.
9.
Observe fuel gauge reading, which should be 9-13 psi.
10.
Depressurize fuel system and remove gage with adapters, then reconnect fuel feed hose to pipe and torque clamp to 15 inch lbs.
11.
Lower vehicle, start engine and check for leaks.
