SERVICE MANUAL UPDATE-SEC.6E2 CHECKING FOR FUEL PRESSURE

MODELS AFFECTED: 1990 BROUGHAMS EQUIPPED WITH 5.7 LITER ENGINE (VIN CODE 7)

The procedure to check fuel pressure in the 1990 Brougham Service Information Manual, Section 6E2, is incorrect because the 5.7L engine fuel lines do not have a Schrader valve. The fuel pressure gage referred to in Section 6E2 (J-34730 or J-38344) is for use with a Schrader valve. Use Kent-Moore gage J-29658 with adapter J-29658-85 to check fuel pressure. The gage and adapter were essential tools for the Cimarron 2.0L in 1984. This pressure gage is installed in the fuel feed line at the throttle body. This throttle body has a constant pressure bleed feature and does not require any special steps to depressurize the system.

Fuel Gage Installation Procedure:

1. Disconnect negative battery cable to prevent accidental fuel pump operation.

2. Loosen fuel filler cap to relieve tank vapor pressure.

3. Remove air cleaner and plug THERMAC vacuum port on TBI.

CAUTION:

A small amount of fuel may be released when servicing fuel lines or connections. To reduce the chance of personal injury, cover fuel line fittings with a shop towel before disconnecting to catch any fuel that may leak out. Place the towel in an approved container when disconnect is completed.

4. Disconnect fuel inlet line at TBI (larger line on left rear of TBI). Refer to Figure 1.

5. Position existing fuel inlet line away from throttle body and install J-29658-85 adapter on fuel line. Refer to Figure 1.

6. Install fuel pressure gage J-29658.

7. Reconnect negative battery cable.

8. Start car and observe fuel pressure reading. It should be 62-90 kpa (9-13 psi); if not, refer to chart A-7 in Section 6E2 of the Service Information Manual.

9. Remove fuel pressure gage and adapter.

10. Reinstall fuel inlet line, start car, and check for fuel leaks.

11. Reinstall the THERMAC vacuum line and reinstall the air cleaner.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.