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Helmsy Helmsy is offline
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Join Date: May 2008
Location: South Australia
Posts: 281
Looks like you are measuring cold control pressure.

Cold starting (when engine is bone cold - left overnight) control pressure will be about 2bar.

If your fuel gauge has a lever then turn it to change from control to system pressure. The system pressure should be about 6 bar (ish).

If you could start your engine you would see control pressure go from 2bar (ish) up to around 3.7+/- bar (ish) as it warms up.

This is the difference between control pressure and system pressure because when measuring control pressure some fuel is returned to the tank.

Also I find it more convenient to just pull the green wire connector from the back of the fuel head than jump fuel pumps. Just my $0.02
'85 930 - Black on Black
'95 993 Turbo - Silver

Last edited by Helmsy; 03-23-2010 at 04:02 AM..
Old 03-23-2010, 03:58 AM
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