A B737-800 FLT CREW DEPARTS THE GATE AFTER PUSHBACK WITH A FAILED R IGNITER ON #1 ENG WITHOUT REALIZING THAT IT IS A NO-GO ITEM AND CANNOT BE MEL'ED.

Narrative

WE HAD JUST FINISHED PUSHING BACK FROM THE GATE IN DCA. ENG #2 START HAD BEEN SUCCESSFULLY COMPLETED AND WE WERE IN THE PROCESS OF STARTING ENG #1. OUR FIRST ATTEMPT WAS ABORTED BECAUSE THERE WAS NO LIGHT OFF WITHIN THE PRESCRIBED TIME LIMIT. AFTER COMPLYING WITH THE QRH PROCS WE MADE A SECOND ATTEMPT WITH THE SAME OUTCOME. WE THEN CONTACTED DCA OPS TO RETURN TO THE GATE. WHILE STILL ON FREQ; MAINT ASKED IF WE TRIED THE OTHER IGNITOR (WE HAD BEEN USING THE R IGNITOR). WE SWITCHED IGNITORS AT MAINT'S SUGGESTION AND SUCCESSFULLY STARTED THE #1 ENG. FROM THIS POINT ON; OUR MINDSET COMPLETELY CHANGED. WE PROCEEDED TO DEPART DCA. DURING OUR CRUISE/CLB; WE DISCUSSED THE PRECEDING EVENT AND REALIZED WE SHOULD HAVE DONE SOMETHING ELSE -- CONSULT THE MEL. IN DOING SO; WE DISCOVERED THE ITEM; THE R IGNITOR; WAS NOT ONLY NOT CREW PLACARDABLE; BUT THAT IT WAS NOT ABLE TO BE MEL'ED; MAINT ACTION WAS REQUIRED. UPON ARR TO MIA; WE CORRECTED THE UNINTENDED OVERSIGHT. SUPPLEMENTAL INFO FROM ACN 624922: DURING CLBOUT (ENTIRE FLT WAS NORMAL). CREW REALIZED THAT AIRPLANE SHOULD HAVE RETURNED TO GATE TO HAVE MAINT LOOK AT THE PROB. UPON REFLECTION; CREW FELT THAT MAINT INADVERTENTLY LED FLT CREW AWAY FROM RETURNING TO GATE TO FIX PROB. CREW ATTEMPTED TO DO THE RIGHT THING; AND WAS SOMEWHAT THWARTED BY MAINT. CAPT RECOGNIZES NONETHELESS THAT IT IS THE RESPONSIBILITY OF THE CAPT; NOT MAINT; TO MAKE THE RIGHT DECISION. FLT CREW UNINTENTIONALLY DID NOT COMPLY WITH THE CORRECT PROC.