Engine Controls - Altitude Adjustments: Overview

Group: 24

No.: 101

Date:
January, 1982

Subject:
ALTITUDE ADJUSTMENTS 140, 160, 1800 240, 260 Models 1968-82

This Service Bulletin is applicable to the U.S. Market and supersedes Service Bulletin Group 24 Number 101 dated September 1981. It contains information designed to improve engine performance of vehicles normally operated at altitude above 4000 ft. (1219 meters).

Altitude adjustments

What is it?

Altitude adjustments are: "adjustments made to vehicle, engine or emissions control function in order to improve emissions at altitudes other than those for which the vehicles were designed."

Why do it?

EPA regulations permit adjustment of vehicles to improve high altitude performance without causing excessive exhaust emissions.


Altitude adjustments will improve:

- exhaust emissions
- engine performance
- engine driveability




The Environmental Protection Agency (E.P.A.) defines:

- High altitude as any elevation of more than 1219 meters (4000 feet)
- Low altitude as any elevation less or equal to 1219 meters (4000 feet)

See list of counties designated by E.P.A. as high altitude counties.


When to do it?

All vehicles are adjusted for low altitude as delivered from the factory.

Certain new vehicles sold for principal use at high altitude (82 and later) must be adjusted before delivery to the customer. This is to be done by the dealer and should be considered part of the normal Pre-Delivery Service.

Owners of vehicles 1968-1981 operating vehicles principally in high altitude areas (above 4000 ft) are recommended to adjust their vehicles for high altitude operation.

NOTE:
Vehicles adjusted for high altitude operation must be re-adjusted to low altitude specifications when the vehicle is returned to continuous low altitude operation.


How to do it?

Carburetor engines (B20B, B30A)
Fuel injection engines (B20F, B21F, B27/28F, B30F)


Counties wholly situated above 1219 meters (4000 feet)







Volvo Dealers located in those counties who are predominantly effected by the regulations, are identified by Dealer Number.