I'm currently working on Husqvarna floor saws. Tier 3 John Deere engines. simple enough. 2.4 power tech 4 cylinder turbo diesel. I just replaced injection pumps and injectors today. I've replaced injectors in the past no problem. according to the service manual the computer needs serviceADVISOR to calibrate the new pump. how crucial is this step? it ran before repairs and now it won't fire up. it's acting like injection is off. I really don't want to take the unit to Deere. deere is charging 300 plus labor for show up to my shop. I can program tier 4 saws on my own but John deere is a pita to access software info. any help is greatly appreciated!