Sender: "Marvin Kaye" <marv@lancaironline.net>
To: lml@lancaironline.net
Date: Sat, 19 Feb 2005 17:18:13 -0500
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From: "glong2" <glong2@netzero.net>
Subject: Capacitive fuel probe problem
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List:

My capacitive fuel probe/oscillator worked fine but suddenly quit. With a
scope I have traced the problem to no oscillations out of the EI probe
oscillator. I contacted EI and they sent new electronics but it did not
solve the problem. Disconnected the probe, connected a capacitor to the
oscillator and all worked as designed.

Traced the problem to a voltage source (~100mv) coming from the probe with
nothing connected to it. Removed the probe as far as possible with the wing
attached, cleaned it as best I could and blew it out with air. Voltage
disappeared. Reconnected everything and now the oscillator works. Let the
system set overnight with no gas and the next day no oscillations - the
probe voltage of ~100mv was back. Removed probe, cleaned again (no voltage)
reassembled and everything worked. Added about 1 gallon of gas and all was
still working. I have not been to the airport today to see if it continues
to work!

Monday I will call EI to see what kind of solvent I can use to clean the end
of the probe without hurting anything. I do not see two dissimilar metals to
generate the voltage, it seems the only way is a weak electrolyte creating
the battery effect. Has anyone else had this problem?

Any ideas on how to fix or clean without removing the wing???

 Eugene Long
Lancair Super ES
glong2@netzero.net