High Altitude Engine Performance Adjustments
83ford6Article No. 83-22-20
ALTITUDE (5.0L) - SERVICE ADJUSTMENT
LIGHT TRUCKS 1984 ECONOLINE, F SERIES AND BRONCO 4-53F; 4-53G; 4-53K; 4-53L; 4-54E; 4-54L; 4-54J; Canadian Leaded; 7-79; 7-80
Customers who may have relocated and/or continually operate the subject vehicle in high altitudes (above 4,000 feet altitude) may have the following procedure performed to improve performance.
All except Canadian calibrations:
1. Remove and retain PCV valve. Install new valve (part no. D90Z-6A666-A) EV-68.
Including Canadian calibrations:
1. Advance ignition timing 4~ above specification located on Vehicle Emission Control Information decal.
2. For vehicles equipped with C6 automatic transmission, remove and discard existing transmission vacuum diaphragm and install altitude compensating diaphragm (part number D8AZ-7A377-A). Attaching vacuum hose must be shortened by 3/4", as outlined in the 1984 Truck Shop Manual (Sect. 17-01).
3. Check and reset idle speeds, as required, per Vehicle Emission Control Information decal.
NOTE: Please return to customer all parts that were removed (except transmission vacuum diaphragm). The parts are to be reinstalled, in the event the vehicle is to be converted to operate at sea level conditions.
If the vehicle is returned to continuous sea level (below 4,000 feet altitude) operation, the above procedures should be reversed and the Vehicle Emission Control Information Update Label should be removed from the vehicle.
Obtain a Vehicle Emission Control Information Update Label (available at all Ford or Lincoln-Mercury dealers) and fill in the appropriate information. In the top paragraph of the label, cross off the altitude (HIGH or LOW) that does not apply and enter the number of the Technical Service Bulletin and Article number that provided the modification instructions. Write in the remarks
as illustrated in the appropriate article, including the new specifications where a space has been provided and the actual numbers have been left blank. At the bottom of the label, enter the date the modification was performed. Select a prominent place adjacent to the Vehicle Emission Control Information decal suitable for installing the label. Do not install the label on any component that can be easily detached from the vehicle. Clean the area, install the decal and cover it with a clear plastic decal shield.
NOTE: The Vehicle Emission Control Information Update Label is a new label to be used for altitude modifications. DO NOT use the AUTHORIZED MODIFICATION$ Label which is used to indicate other types of modifications.
PART NUMBER PART NAME CLASS
D90Z-6A666-A PCV Valve A
D8AZ-7A377-A Transmission Diaphragm AM
OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: Reimbursable within the provisions of the Warranty and Policy Manual.
OPERATION: M
TIME: "Actual Time" as defined in the Warranty and Policy Manual. DLR. CODING: Basic Part No. DRIVE Code: 53