Delta 88 V8-350 5.7L DSL VIN N FI (1983)
Emission Control Systems: All Technical Service Bulletins
Diesel Engine - Altitude Performance Adjustments
SUBJECT
NUMBER: 83-T-8
1983 OLDSMOBILE ALTITUDE PERFORMANCE ADJUSTMENTS
5.7L V-8 DIESEL ENGINE
DATE:
May 16, 1983
The 1983 Oldsmobiles equipped with 5.7L V-8 diesel engines will be manufactured with either high or low altitude diesel systems. A vehicle with a high
altitude system will be invoiced with option NA6. The type of system can also be identified by the emission label attached to the fan shroud. The label
will indicate that the vehicle was designed for principal use at either high or low altitude.
These adjustments are considered Altitude Performance Adjustments and apply only to in-use vehicles. They should not be used to modify vehicles prior
to sale.
Dealers must not sell vehicles with low altitude systems for principal use at high altitude.
CONVERSION OF LOW ALTITUDE SYSTEM TO HIGH ALTITUDE
Dealers in high altitude areas should encourage owners who have moved to high altitude counties to purchase the service adjustment procedure outlined
below, which is considered an owner maintenance expense. See attachment for a list of counties which the Environmental Protection Agency has
designated as high altitude counties. Diesel timing should be checked or adjusted at the same approximate altitude at which the vehicle will be driven.
FIGURE 1
1.. Replace the EGR vacuum control valve assembly (Figure 1) with the assembly shown in the parts information.
2.
Install timing meter J-33075 or equivalent, set pump timing -4~, and set idle speed to specifications.
3.
Remove air cleaner and air crossover assemblies and install screen covers J-26996-2.
