G 20 3/4 Ton Van V8-305 5.0L VIN H 4-bbl (1984)
FIGURE 4 - VEHICLE EMISSION CONTROL INFORMATION UPDATE LABEL - P/N 14055121
VEHICLE EMISSION CONTROL INFORMATION UPDATE LABEL
The label should be affixed in a readily visible position in the engine compartment and where possible beside an existing Emission Control Information
(Tune-Up) label and should not be affixed to any equipment that can be easily detached from the vehicle.
Prior to installation of this label, the dealer code number and date of modification must be typed (with or without ribbon) or lettered with ballpoint pen in
the space provided.
The label can be ordered as outlined in GM Standard Parts Catalog #89, P/N 14055121 (see Figure 4).
DEALER AND CUSTOMER INFORMATION
Owners of 1984 high altitude vehicles taking up permanent residence in low altitude counties, should be encouraged to have these adjustments performed
when vehicles are brought in for service.
After performing these adjustments, dealers should advise customers that, IF THE VEHICLE IS RETURNED TO CONTINUOUS HIGH ALTITUDE
OPERATION, THE ENGINE SHOULD BE RE-ADJUSTED TO HIGH ALTITUDE SPECIFICATION PER THE CORRECT CHASSIS SERVICE
MANUAL FOR IMPROVED HIGH ALTITUDE PERFORMANCE. IF RE-ADJUSTED TO HIGH ALTITUDE SPECIFICATIONS, THE
SUPPLEMENTAL LABEL SHOULD BE REMOVED.
PROCEDURE II
To be used for all the following 1984 high altitude (NA6) engines used primarily at low altitudes.
Light Duty Federal Emission Packages
^
1.9L Federal
1.
Remove vacuum delay valve from the diverter valve vacuum line. (Refer to Emission Hose Routing on Emission Control Information Label.)
2.
Adjust idle speed to specifications.
^
2.0L Engine
1.
Retard timing as much as 4~ from the basic specification if knock occurs at low altitude.
2.
Re-adjust idle speed to specifications.
^
2.8L Federal
1.
Retard ignition timing as much as 2~ from specification if spark knock occurs at low altitude.
2A.
Automatic Transmission.
-
Adjust curb idle speed from 700 RPM in D to 650 RPM in D.
2B.
Manual Transmission.
-
Reset curb idle speed to 700 RPM in N.
3.
Reset A/C solenoid speed to 850 RPM in D automatic and N manual. Fast idle speed to 2100 RPM in P or N automatics and N manuals.
^
4.1L Federal
