Nissan Pick-ups and Pathfinder 1970-1988

High Altitude Compensator System

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OPERATION



See Figures 1, 2 and 3

Gasoline Engines Only

When the truck is operated at particularly high altitudes, where the air is thinner, the mixture ratio and intake manifold boost vary greatly; exhaust emissions also increase considerably. In order to decrease these emissions, an altitude compensation system is employed to correct the air/fuel ratio to that of sea level.

When the atmospheric pressure decreases (as altitude increases) to a certain value, an altitude switch is turned on, applying voltage to an altitude solenoid valve. When the solenoid valve turns on, additional air is let into the carburetor, allowing a leaner air/fuel ratio.



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Fig. Fig. 1: High altitude compensator system-1981-83



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Fig. Fig. 2: High altitude compensator system-1984



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Fig. Fig. 3: High altitude compensator system-1985-86

 
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