First, this is a p-ported 3-rotor, running RWS EC-2 and psru.  I'm running 460cc Mazda primary injectors and 60lb Deka IV secondary injectors.  Primary injectors share a common fuel rail and are positioned close to the engine, between throttle plate and rotor face.  Secondary injectors are located ahead of the throttle plates.  As this is a p-port engine, it has three 1-bbl TB's, located very close to the engine.  Engine will idle down to 800 - 900 rpm, but I normally idle it around 1500 - 1600 rpm.

 

The problem is this, the #1 rotor cuts out at low to mid-range RPM, evidenced by obvious reduced power, very low EGT's on rotor #1, change in exhaust tone, a dark residue in the #1 exhaust port and dark spark plugs on #1.  Just today I was able to get it to run normally with balanced EGT's by adjusting Mode 4, but I had to go full CCW with the program knob to achieve this.  (Mode 4 & 5 adjust similar to Mode 1)  Now it runs well mid-range and the dropped #1 rotor is happily firing away.  I still have some tuning to do, but after adjusting Mode 4, I can now move forward with that.  

 

To date I have tried the following:

  1.  Performed a compression check - OK

  2.  Swapped primary injector with #3 - no change

  3.  Swapped coils with #3 - no change

  4.  Replaced spark plugs - no change, except initially it ran better until the plug fouled

  5.  Checked plug wires with ohm meter - checked good

  6.  Sent EC-2 to Tracy for latest s/w and checkout - no abnormalities found, latest s/w installed

  7.  Checked secondary injectors for leakage - none seen

 

Can anyone suggest a reason why the #1 primary injector runs extremely rich when set to the factory default setting?  Is this something to be concerned with?

 

Thanks,

Mark