Conversion of High Altitude Vehicles to Low Altitude

Dealers should advise owners moving to low altitude areas that they should purchase the service adjustment procedure outlined below which is considered an owner maintenance expense.

1. Replace the EGR valve vacuum control assembly (Fig. 1) with the assembly shown in the parts information.

2. Remove air cleaner.

3. Determine if the injection pump contains a pressure tap plug or a metering valve stop screw (Fig. 2).

4. If equipped with a pressure tap plug go to step 6.

5. If equipped with a metering valve stop screw, remove air crossover, loosen lock nut and turn stop screw out (counterclockwise) four to five turns. Tighten lock nut and install crossover.

6. Install air cleaner.

VEHICLE EMISSION CONTROL INFORMATION UPDATE GENERAL MOTORS CORPORATION:

7. Type or print with ball point pen the dealer code and date in the space provided on the supplemental emission control label, part number 14055121 or equivalent (Fig. 4). The label must be placed next to the existing underhood emission control information label to the extent possible. The label should not be affixed to any equipment that can be easily detached from the vehicle. Wash off the area with soap and water, dry thoroughly and apply the new label.

PARTS INFORMATION

Part Part Number

1. EGR Valve Vacuum Control Assembly Low Altitude Application

All Models Except Estate Wagon 3-Speed A/T 22514746 or equivalent

Estate Wagon w/3-Speed A/T 22512323 or equivalent

2. Label 14055121 or equivalent (See Figure 4)

Suggested Time

The suggested time to perform the Low Altitude adjustment and part replacement procedure listed above is 0.4 hour labor