Remote Start, turns over, no start.

2002 Honda Civic LX 2dr.... using an Avital Keyless Entry + Remote Start system....

Keyless entry works perfectly, remote start doesn't.  It turns over but doesn't start.  DEI immobilizer installed, car doesn't remote start with key in or key in on position.  The car just turns over for a second or two.... then try to start again in 5-10 seconds.  This is my wife's car.  I drive the exact same car and have the exact same system, however my brother installed it in mine.  When I iniate my remote start, I can hear kind of a hum before the car attempts to turn over... so my guess is, whatever that hum is, my car isn't starting it correctly.

 Hum may be fuel pump. Ignition may be a little weak; requiring a longer crank time. Tach wire hooked up?

Just a couple of guesses.

That hum is the fuel injection on the Honda's, this is normal. You have to learn the tach on this unit. Did you attach the tach wire to the Avital ? Make sure that you have the DEI unit's ground out when running wire attached to the proper wire on the Avital. Post your results

Check installtion of 555U ... might not getting signal of key from unti to car.make sure antina ring of module is right.

to check this just put key in cylinder do not turn .. .disconnect 555U before this .. .try to start with remote start ..if it's start then for sure it's not getting signal from 555U unit

555U unit... tach is hooked up, anyway to test if it is getting signal?  The tach is connected to the Avital, and yes, the ground-out-when-running is connected to the correct (negative status output) on the Avital.  I disconnected the 555U, put the key in the cylinder, and tried to start.  Still no go.  I tried learning the tach wire (hit the programming button) but the LED doesn't flash in the end like the manual says it should.