Mailing List flyrotary@lancaironline.net Message #6061
From: David Leonard <Daveleonard@cox.net>
Subject: RE: [FlyRotary] Re: 13B - No start problem
Date: Sat, 28 Feb 2004 23:59:48 -0800
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Message

Ed & Rusty,  thanks again for your replies.  Today I went out to the hangar and solved the issue, … it’s very strange.   I started by applying an ohm meter across the injector leads with the fuses removed.  As we would expect from my problem one lead (hot lead) would indicate no connection with ground while the other showed some current flow, but not zero resistance with ground, 1.2  Kohms (or 0.2 Kohms if I reversed the polarity of the ohmmeter)…. (scratch head and look dumbfounded).  The same with the other injectors.  Hmmmm.

 

On a hunch I went and turned on the main power to the EC2 and re-tried the above experiment.  Low and behold, there was no longer any current to ground. (infinite resistance both leads).  The system would hold fuel pressure and all was right in my little world.  In other words, if there is power to only the injectors the EC2 seems to need some current and will draw across the injectors causing them to open.  But if I applied power to the main EC2 power input, the EC2 had enough power to properly close the injector circuits.  I repeated the entire experiment to make sure I wasn’t seeing things.

 

Now that I know how things work, it wont be a problem….  But still I haven’t run the engine…  J  (i.e. and sure to be in dire straits again soon)

 

Thanks again for your help.

 

David Leonard

The Rotary Roster:

http://members.aol.com/_ht_a/rotaryroster/index.html

 

I am also having trouble picturing where I could have gone wrong in the wiring.  It seems unlikely to me that I could have grounded all 4 of the injector leads.  Your idea about testing with the main connector unplugged is a good place to start.  But assuming that checks out OK (no ground with the connector unplugged), I really would have no idea what to do next.  I can’t believe that I would put all 4 injector leads in the wrong hole.  BTW, I did not install an injector disable switch.

 

 

Hi David,

 

Ed's message is great, and I won't try to add much to it. 

 

I did just take a look at the EC-2 plug again, and noticed that the primary injector wires are pins 17 and 18, with a ground on 19.   The secondary wires are pins 35 and 36, with the ground on 37.  These are supposed to be larger wire than the rest, so they don't fit as well in the plug.  All it would take is a strand of wire between 18 and 19, or between 36 and 37 to cause one injector to open up when you apply power.  I'm betting you'll find your problem in the connector.    Of course it also wouldn't be too hard to accidentally swap one of the injector wires with one of the grounds, which might do it too.  Naturally, I would never make such a mistake (ahem...)  :-)

 

Good luck,

Rusty (off to TIG some stainless) 

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