From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Al Gietzen
Sent: Monday, April 10, 2006 10:43 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: FI mystery

Since we are looking for something obscure here I would check the voltage to the fuel injectors.  Low voltage would make for a lean mixture.  Other items are:

2.  vacuum line disconnected

3.  air leak

4.  fuel pressure

 

Haven’t checked the voltage to the injectors yet; so I can do that.

 

Checked - No vacuum line leaks; no lines out of place. Leak in MAP line would give a higher MAP reading and too rich a mixture.

 

Checked - No air leaks – would take a major leak downstream from the injectors to give these symptoms.

 

Fuel pressure is normal.

 

Did you try both controllers? 

 

Tried both controllers – same behavior.  Looked at the mixture correction table on the EM-2; things look normal.  The mixture “map” would have to be WAY off to require ‘cold start’ switch on.

 

The only thing I noted as abnormal was that the EGT on rotor one was not stable; seemed to be ‘hunting’ around the values of the other two.  Since the engine was running smooth and steady, I attributed this to something related to the TC, like poor connection, TC going bad, etc.  I can find no connection between this and a way to lean mixture w/o cold start switch on.

 

Al (still baffled)