Received-SPF: none
 receiver=logan.com; client-ip=206.191.0.217; envelope-from=pcasson@sasktel.net
Message-ID: <4323BBDF.9000404@sasktel.net>
Date: Sat, 10 Sep 2005 23:08:47 -0600
From: Perry Casson <pcasson@sasktel.net>
User-Agent: Mozilla Thunderbird 1.0 (Windows/20041206)
MIME-Version: 1.0
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: mystery inflight fuel pressure drop
References: <list-718116@logan.com>
In-Reply-To: <list-718116@logan.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

Had a small issue on my last flight that I can not explain - anyone care 
to venture a guess what was going on?

I was hmmmm-ing along at 7500' on friday about 60 minutes into a 2 hour 
flight when my EIS low fuel pressure alarm went off and fuel pressure 
had dropped to 29 psi (alarm set at 30 psi) and the engine went a bit 
lean.  I switched on my backup pump and fuel pressure instantly went 
back to the normal 38 psi.  Flew like that for a couple minutes and then 
decided to do I bit of investigation so I turn the backup pump back off 
but the fuel pressure remain at the normal 38 psi for the rest of the 
flight.  No other problems other than I seem to be running a bit leaner  
than normal for  a 12 o-clock setting on the EC-2 mixture control.

My install is pretty much a clone of Tracy's pre-Renisis fuel system 
other than I've got a high wing (Glastar). Feed and return from left 
tank, fuel line y after a fuel shutoff valve, inline fuel filters 
upstream of  parallel  Federal  Mogul pumps  mounted on cockpit  side of 
firewall, using stock 89 RX-7 pressure regulator, 88 NA Injectors, no 
damper. 

I've been try to come with a explanation that would account for such a 
issue and other than the fuel pressure regulator may have got stuck and 
the extra flow from turning on the second pump unstuck it.

Perry Casson