REVISED IDLE ADJUSTMENT SHOP MANUAL UPDATE

VEHICLES AFFECTED: 1986 SPECTRUM SHOP MANUAL

The Idle Mixture Adjustment Procedure for Steps 3 through Steps 8 are being published to replace information found in the 1986 Spectrum Service manual (ST-371-86) Page 6C8-14.

3. Reinstall the carburetor and air cleaner.

4. Before setting idle mixture, perform the following steps:

a. Set the parking brake and block front and rear wheels.

b. Place transmission in neutral (M/T), "P" Position (A/T).

c. All accessories switched off.

d. If equipped with power steering, place the front wheels in straight forward position.

e. Check ignition timing.

f. Make idle speed adjustment with engine at normal operating temperature, choke valve open, air conditioner off if equipped and air cleaner installed. Wail until the cooling fan stops when it is operating.

Distributor vacuum line (Carburetor to distributor), canister purge line, EGR vacuum line and ITC valve vacuum line disconnected and plugged.

5. Adjust the mixture.

a. Adjust the idle speed by turning the idle speed adjusting screw. See Figure 6C8-20.

b. Connect the positive (+) side of the dwell meter to the duty monitor lead and ground negative side. Then, after setting the dwell meter dial to the 4 cylinder or 6 cylinder scale, adjust by the idle mixture adjust screw so that the dwell becomes 45 degrees on 4 cylinder scale or 24 degres on 6 cylinder scale.

c. Repeat Steps a and b.

d. Connect a tachometer.

e. Adjust the idle speed by turning the idle adusting screw. See Figure 6C8-20.

f. Set dashpot.

6. Drive in a new plug.

a. Remove oil from the carburetor side hole and the plug.

b. Apply Locktite Sealant P/N 992959 or its equivalent to the plug.

c. Drive in the new plug up to the carburetor surface.

7. Adjust idle speed of vehicles with A/C.

a. Start the engine.

b. Connect all hoses.

c. Turn A/C on Max. COLD and high blower.

d. Turn the adjust bolt of FICD and set the fast idle to 850 rpm (M/T) or 980 rpm (A/T). See Figure 6C8-21.

8. Check the fast idle speed.

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.