Porsche 1972 911 Workshop Manual page 170

Beginning with 1974 models, Type 911 and 911 S, vehicles are equipped with the continuous injection
system.
1. Cast intake pipes with mounting hole for injection valves.
2. Repositioning of the injection valves resulted in their being lengthened and injection lines
shortened.
The diameter of intake pipes at the intake housing has been changed:
3.
Intake pipe for Type 911
4. Mixture control unit has been calibrated for 2.7 liter engines.
5. The pneumatic valve has been repositioned and also modified to the vacuum characteristics
prevailing in the 2.7 liter CIS engines.
6. The cold start enrichment valve has been moved to the center of the intake housing to effect a
better distribution of the fuel to the individual cylinders.
7. A thermoswitch has been mounted on the left chain housing cover to supplement the cold start enrich-
ment valve.
C O N T I N U O U S I N J E C T I O N S Y S T E M ( C I S )
C h a n g e s E f f e c t i v e w i t h 1 9 7 4 M o d e l s
31 m m dia.