Have you checked the pressure switch and also to assure that the flu is clear? can you light the burner with a match and when you do how long does it run for? have you checked the clearance to the burner have you also assured that where the ignitor is pluged into is cleaned ive also noticed on another site there is a board issue with this model have you checked the board ? also have a look at this site as well its where I usually talk with other techs about issues they have with the goodman as well as other units http://www.contractortalk.com/f6/goodman-80-furnace-brand-new-wont-start-7006/ please message me back with the answers to the questions that I have asked and I await your reply Thanks again Rick