1978-79 Models

Connect pressure gauge and valve assembly as in cold engine control pressure test. Be sure that control pressure regulator is connected. Disconnect airflow sensor. On 928 models, be sure plug to auxiliary air regulator is also installed.
On all models, open valve on pressure gauge. Turn ignition on and wait 2-3 minutes. Check pressure with engine stopped. Start and run engine at idle speed until engine reaches normal operating temperature. Check pressure once again. Pressures should be as specified in WARM ENGINE CONTROL PRESSURE TEST table. If not, replace control pressure regulator.

WARM ENGINE CONTROL PRESSURE TEST

Application

Stopped psi (kg/cm² )

Idling psi (kg/cm² )

924

49.3-55.1 (3.47-3.88)

911SC

39.2-45.0 (2.75-3.16)

46.4-52.2 (3.26-3.67)

928

41.3-45.7 (2.91-3.21)

50.0-54.4 (3.52-3.82)

930 Turbo⁽¹⁾

49.3-55.1 (3.47-3.88)

⁽¹⁾	With boost pressure above 4.36 psi (.32 kg/cm² ), warm control pressure should be 39.2-45.0 psi (2.75-3.16 kg/cm² ). Boost pressure at 4000 RPM should be 11.6-12.6 psi (.82-.89 kg/cm² ).