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Alan L Alan L is offline
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Join Date: Apr 2006
Location: New Zealand
Posts: 3,261
which WUR reading to believe?

I have set my WUR pressures up statically - ie without engine running.
I have several CIS manuals, some call for engine running on some cars, but no reference for Porsche to do so. Most just say hook in gauge, bypass fuel relay, ignition on.
I've been hooking mine in, key on, and just depressing airplate for steady reading - which I have taken as cold pressure. For Hot, I have either hooked in when car is hot and done same, or dummied power to WUR from cold, and watch pressure rise.
Now I have been doing some tests with engine running.
The numbers are completely different.
From cold, my static pressure will rise by 15-20 psi after I start engine - even with power to WUR disconnected, and WUR remote from engine block - within 60 sec.
Similarly, my system pressure pegs my gauge under these conditions - who knows how much, but statically it is set at 95 - which is where the book says it should be. But under running conditions it seems to be well over 110 psi.
I would imagine the running numbers are the real deal - what my engine is actually seeing - but they are way different to the static numbers.
Why the difference, and which ones to use?
Old 07-30-2008, 11:35 PM
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