High Altitude Service Adjustment
83ford19 Article No. 83-7-23ALTITUDE SERVICE ADJUSTMENT - 49 STATES - 3.8L ENGINE
LIGHT TRUCKS 1983 F100
CALIBRATIONS: 3-55D and 3-56D
Figure 15:
Customers who may have relocated and/or continually operate the subject vehicles in high altitude (above 4000 ft.) may have the following service modification performed to improve performance:
1. Remove the pullover air bleed (9A521) from the top of the air horn. Use a small plug remover or a sheet metal screw of suitable size (Figure 15).
2. Advance the initial ignition timing 6~ from the specification on the Vehicle Emission Decal (3-56D Only).
NOTE: At this setting, unacceptable detonation may be experienced if the vehicle is operated at sea level.
3. Reposition the choke actuating rod to the altitude position (3-55D Only) (Figure 15).
4. Remove and discard existing C5 transmission vacuum diaphragm (D6AP-7A377-AA) and attaching clip. Install altitude compensating diaphragm (D7DZ-7A377-A) with (D8BZ-7F006- A) attaching clip.
5. Check idle mixture by artificial enrichment (propane). Gain to be 10-30 RPM, if not reset to 20 RPM. Reset speeds to the spec on engine decal.
NOTE: The carburetor Air Fuel Adjustment must have the Adjustment Limiting Feature reinstalled.
TO REVERT TO SEA LEVEL, PROCEED AS FOLLOWS:
a. Install a (E2TZ-9A521-A) (.033) pull-over air bleed into the pull-over tube hole at the top front of the air horn. (Previously removed in Step 1.) Use a 1/4" drift punch - tap lightly.
b. Remove the choke plate lever screw and reposition the rod to non-altitude (STD) hole and reinstall screw on 3-55D only.
c. Reset initial ignition timing to original specification on Vehicle Emission Decal.
NOTE: The C5 Transmission Vacuum Diaphragm is self-compensating and does not require replacement.
d. Check idle mixture by Artificial Enrichment Method (propane). Set to sea level specification. Reset speeds to the original decal spec.
NOTE: The carburetor Air Fuel Adjustment must have the Adjustment Limiting Feature reinstalled.
e. Remove altitude modification decal.
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 label 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 Modifications Label which is used to indicate other types of modifications.
PART NUMBER PART NAME CLASS
D7DZ-7A377-A Transmission Diaphragm A
D8BZ-7F006-A Clip C
E2TZ-9A521-A Air bleed CG
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
PROGRAM CODE: L05 (The program code is to be entered in the Program Code Box on the Warranty Claim Form 1863.)