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Probably not Dave,

The first fuel injection system I flew with was an after market HALTECH unit. It had a similar arrangement to the MicroTech (and is also made in Australia) , if no ignition signal was detected after 2 seconds or so, it would open the relay providing power to the fuel pump. True you could have a pressure sensor in the fuel line although I have not yet heard of a unit with one there (I think expense of the sensor is probably one reason). However, another similar approach to the one you suggested that I have seen used - is to use a pressure sensor in the engine oil lubrication system. If no oil pressure within a set time implies the engine did not start and the relay will open cutting of power to the fuel pump.

----- Original Message -----

From: David Staten

To: Rotary motors in aircraft

Sent: Monday, May 02, 2005 8:53 AM

Subject: [FlyRotary] Re: fuel pumps/forced landing

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 -----

From: sqpilot@bellsouth.net

To: Rotary motors in aircraft

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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