911 CIS SYSTEM PRESSURE
08-27-2002, 03:52 PM
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911 CIS SYSTEM PRESSURE
PER BENTLEY MANUAL,SYSTEM PRESSURE FOR A 1974 911
CIS K-JETRONIC SHOULD BE 70-75 psi. WHAT IS THE MINIMUM PRESSURE? A PORSCHE MECHANIC TOLD ME THAT OLDER CARS RUN FINE AT 50-55 psi SYSTEM PRESSURE
AND 15-20 psi CONTROL PRESSURE. RATIONAL BEING THAT SPEC'S ARE BASED ON NEW CARS. YOU ONLY NEED ENOUGH PRESSURE TO OPEN INJECTORS WHEN THE ENGINE IS CYCLING ON THE VAC. STROKE.
<img src="confused.gif" border="0">
CIS K-JETRONIC SHOULD BE 70-75 psi. WHAT IS THE MINIMUM PRESSURE? A PORSCHE MECHANIC TOLD ME THAT OLDER CARS RUN FINE AT 50-55 psi SYSTEM PRESSURE
AND 15-20 psi CONTROL PRESSURE. RATIONAL BEING THAT SPEC'S ARE BASED ON NEW CARS. YOU ONLY NEED ENOUGH PRESSURE TO OPEN INJECTORS WHEN THE ENGINE IS CYCLING ON THE VAC. STROKE.
<img src="confused.gif" border="0">
08-27-2002, 05:21 PM
#2
4.8-5.2 BAR, SYSTEM PRESS, AND 3.4-3.8 BAR, CONTROL PRESS. ROUGHLY 70-76#, AND 50-56# RESPECTIVELY. MUCH MORE OR LESS, THEN IT'S NOT IN SPEC, AND WON'T RUN PROPERLY, REGARDLESS OF AGE.
