Good evening Mr. Lamar and other rotary people,

 I have a starting problem with my rx8, 2004, hi-power version.   108 000
KM.  My car will not start.  I replace apex seals and all parts which was
bad, but engine not start too.  I replace starter 2004, e-shaft position
sensor, igniton coil + cables, spark plugs, knocking sensor, throttle body
activator, SSV actuator,.  Engine allways wont start, but when we pushing
car, on 10 metres car start, and car drive ok, but engine has a unstable
idle, 750 -1500.  Please help me.  Jaroslav Dibala

    You need to get an OBD II program for your PC computer and a special
 cable that connects to the OBD II connector under the dash.
 That will tell you what is wrong.
 Obviously none of the stuff you changed so far was the problem.
  http://www.scantool.net/
 http://www.obdsoftware.net/
 http://www.myscantool.com/
 http://www.obddiagnostics.com/
 http://www.obd-2.com/
 http://www.autotap.com/
 http://www.obd2crazy.com/
  Paul Lamar

 Thank you very much, but I was on PC in Mazda service. PC tell
me   that   range of ex.shaft position sensor is bad, and second
rotor   has not good   combustion.   Jaroslav Dibala
 Well if the shaft sensor is bad the engine will not run.
 The latest thinking on early 2004 2005 RX8 problems is the
newly   designed coils   were misfiring allowing the unburnt
fuel to wash the apex seal oil   out of the engine. Check the
coils that you have now.   If the part number marked on the side
of the coils is not   followed by a "B" replace the coils.
 If the rear rotor compression is still low the engine
   will need to be over hauled. With less than 100,000
   miles (not kilometers) it will be done by Mazda
   for free.
 Paul Lamar

Hi Jaroslav,   I am not a rotary mechanic, but, it sounds to me
that you   should check, a - check the voltage to the ignition
system, while   attempting to start the engine, b,- check the
voltage at the starter,   while attempting to start the engine. It
sounds to me that there is not   much wrong with the engine if it
will start and run whilst push-starting   the car. It is probably
electrical because it will not start on the   starter.  John
  Burey.

 John, the wrong name was attributed to the original message so
I  changed   your response to correct that. Jaroslav Dibala  is
the correct name.
 Good call. I don't know why I did not think of the obvious.
   I guess personal cars are rather new in the Slovak Republic
   or perhaps Jaroslav is a new and inexperienced mechanic.
   Those of us here in North America and Western Europe grew
   up with cars since Henry Ford. We take certain car knowledge
for   granted.
 Paul Lamar

 I´m not a new mechanic :).
  I make some rx 8 engine with p-port too. Voltage is o.k.,  Next
  problem
  is idle, is unstable between 750-1500 rpm.
 Jaroslav Dibala
   Are you using the stock computer with a p-port?
  That is unlikely to work.
   Paul Lamar

   no, no... i have a p-port engine in another car with racing ECU,
 it  works perfectly.
 I'll try to replace oxygen sensor.
Thank you very much.
 Jaroslav Dibala

Jaroslav,
If you have an OBD2 reader, find the O2 area and watch the output volts.  It
  should bounce around.  The sensors output 0 to 1 volt with a target of
  0.5V. If  it is working well it will be above and below the 0.5V
fairly quickly.  Some  readers have a "cross counts" screen. You
want a high number of cross  counts.  This is the number of times
per second the O2 passes 0.5V. An old  sensor will  not respond well
and not have a bouncing around output.  To verify if the sensor
circuit back to the computer (ECU) is good,  disconnect  the wiring
harness at the sensor. Put a pin or piece of wire in the  sensor
 wire. Not the ground for the sensor or the heater wires. Then you hold the
   pinh or wire and touch the positive and then negative battery terminals
  with your other hand.  This will drive the sensor circuit high and low
  but not damage the ECU.  With the reader connected you can watch the O2
  volts.  With 108.000 Km the O2 sensor is probably getting poor.

Do you have access to a lab scope? If you do you can connect it to
the  e-shaft  position sensor circuit. Three wires; +12V,ground and
signal. signal  is the  wire to probe. A pin works well to slide in
between the wire and seal.  when  running the scope should show a
good straight line and then jump high  or low  and then return to
start position. No curve at change of state and no  breaks  in the
straight line other than the change of state. Breaks in the line
 indicate failing sensor.
Dale Davies

 As i said before I am not a Rotary mechanic but usually the Oxy
sensor is not read at idle, usually because the engine needs to be
run much richer at idle, so the sensor is open loop until a certain
speed is reached then the o2 sensor goes closed loop, sometimes the
switching is done by the Throttle position Switch, maybe it is
closed loop when it should be open loop. But that should not affect
starting when it starts with a push, a lot of times the ignition
switch will go open circuit in the ignition circuit when turned to
start, very frustrating:-[ . But at 100,000km the switch should have
not worn out. You could have a vacuum leak in the inlet manifold
,rubber hose?  John Burey

The system is in open loop during warm up as Matt said, and then during full
throttle. Outside that it is closed loop. The O2 is for trimming the mixture
the is determined by the other sensors; TPS,ECT,MAF or MAP. The newer O2
sensors are all heated so they come up to temp and start reading sooner. Also
the heated ones can be put farther down stream where the exhaust temp would
cool quickly and they would become ineffective at idle too soon. Poor O2 will
cause idle problems.

A vacuum leak is a good call for erratic idle. Too frequently we forget the
basics, and blame the electronics. Could be part of the starting problem also.

Dale Davies