Mailing List flyrotary@lancaironline.net Message #21424
From: Paul <sqpilot@bellsouth.net>
Subject: Re: [FlyRotary] Re: fuel pumps/forced landing
Date: Wed, 4 May 2005 23:43:44 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Hi, Kelly....the only problem I see here is that there is a benefit to having the ECU turn off the fuel pump if it detects no spark. This would prevent the engine from flooding. If the fuel pump kept pumping fuel under high pressure, either the injectors dumping fuel into the engine, (or fuel leaking by the injectors if the injectors are no longer firing) could make it difficult to restart once you have regained ignition/spark.  Just one more thought.  Paul Conner
 
----- Original Message -----
Sent: Monday, May 02, 2005 11:17 AM
Subject: [FlyRotary] Re: fuel pumps/forced landing

Cannot resist adding fuel to the fire !!.........Even though a logic circuit is used in
automobiles to start and shutoff the fuel pump as a safty feature I do not intend
to use this feature in my A/C....... In the event of a power off unplanned landing
we are taught to turn fuel off........Same procedure should be followed no matter
if done with a manual valve or a electrical switch and/or circuit breaker....IMHO
 
Kelly Troyer
Dyke Delta/13B/RD1C/EC2




-------------- Original message from David Staten <Dastaten@earthlink.net>: --------------

The"ignition" system is shutting off the pump once adequate head pressure is obtained. Its not the engine starting that directly triggers the pump. Its the engine using the fuel in the rail, lowering the pressure below the triggering threshold on some pressure sensor somewhere, causing a logic circuit to turn the pump back on. The feedback loop in this situation is based on fuel pressure.
 
Dave

William wrote:
Paul,
If your ignition system shuts off the pump with no spark, isn't the following going to happen?
 
Pump 1 on -- engine running,
pump 1 fuse blows, engine shuts down very quickly,
Pump 2 turned on, but no spark since engine has stopped, therefore it shuts off right away.
 
Sounds like if engine stops, you have to crank it to get it started again
Bill Schertz
KIS Cruiser # 4045
----- Original Message -----
Sent: Monday, May 02, 2005 1:42 PM
Subject: [FlyRotary] Re: fuel pumps/forced landing
 Turned on the other pump, but the engine had already quit. (yes, it happens very fast)  
 
      I now recall reading in the MicroTech manual that the fuel pumps shut off if it detects no spark from the coils, so that it would not continue pumping fuel into an engine that has no spark. This is obviously why the pump only runs for a few seconds when I first turn on the ignition switch, then quickly stops pumping. We put a voltmeter to the inline fuse, and found that it had 12.9 volts as soon as the ignition was turned on, but after a few seconds, the pump stopped and there was no longer any voltage at the fuse.
    I'm hoping we can find what caused the slight fuel obstruction in front of the gascolator....if we can't find the cause, it would be difficult to regain confidence in the fuel system. Too bad, because the engine was running strong and smooth, and the temps were great!!!  Paul aka deadstick Conner

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