SERVICE MANUAL UPDATE SEC. 6 VACUUM TEST PROCEDURE

SUBJECT: SECTION 6 VACUUM TEST PROCEDURE

VEHICLES AFFECTED: 1993 "M" MODEL GEO METRO

APPLICATION: 1993 Geo Metro

This bulletin replaces the "Vacuum Test" procedure in Engine General information and Mechanical Diagnosis (Section 6) of the 1993 Geo Metro Service Manual (ST370-93)

VACUUM TEST

1. Start engine and allow it to reach normal operating temperature. Make sure that the engine idle speed is between 700 to 800 rpm. 2. Stop engine and install a vacuum gage between the manifold absolute 0 Disconnect the MAP sensor vacuum hose from the TB. 0 Using a three-way vacuum hose joint and two pieces of vacuum hose, connect a vacuum gage between the MAP sensor and the TB (Figure 1). 3. Start and run engine at idle.

MEASURE

Engine vacuum pressure. Standard vacuum pressure is 52.9 to 66.3 kPa (1 5.7 to 19.7 in.Hg) at 700 to 800 rpm.

4. Stop engine and remove vacuum gage, three-way joint and extra vacuum hoses. 5. Reconnect MAP sensor vacuum hose to TB.

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.