Engine - Performance Altitude Adjustments: Overview

86chevy10

Number: 86-46

Section: 6E

Date: MAY, 1986
Subject: ALTITUDE ADJUSTMENTS FOR ENGINE PERFORMANCE


Model and Year: 1986 C,K,G,P - 10-30 FEDERAL EMISSION TRUCKS EXCEPT H.D. DIESEL
TO: ALL CHEVROLET DEALERS


This revised Dealer Bulletin cancels and replaces 86-46 dated March, 1986 which should be destroyed. This reissue reflects correct model usage, from all 1986 Trucks to 1986 C,K,G,P - 10-30 Federal Emission Trucks Except H.D. Diesel.

The adjustments specified within this bulletin are intended for vehicles currently in customer use and do not apply to new vehicles in dealer inventory. The adjustments are provided for the purpose of vehicular performance and customer satisfaction of emissions specifications for the involved vehicles.

This bulletin has been divided into two (2) procedures. Procedure I is applicable to Low Altitude (NA5) trucks taking up permanent residence in a high altitude county. Procedure II is applicable to High Altitude (NA6) trucks being used primarily in low altitude counties.

The only exception is the closed loop (Computer Command Control) system which is self compensating for altitude. Applicable engines which require no adjustment are the 2.5L, 2.8L, 4.3L, 5.0L, and 5.7L California, and all engines in Federal "M and S" trucks.