"i was testing old glow plug ina 1999 7.3 and one grounded on an injector. I replaced all of them since 3 were bad and didnt take much more labor. when job was finished it wont start. it will fire in either but that is it. wondering if the one grounding on an injector could have done any damage andif anyone has any ideas on what to check from here."

Follow Item 3, below, and check all fuses. You may have shorted something out.

https://www.askmehelpdesk.com/cars-t...ml#post1415281

Got it fixed the next morning. Spent too much time re- checking my work chasing my tail. Didn't have anything to do with what I was working on. Really I expected it something else to be wrong since it wouldn't start in 50 degree weather with 5 good glow plugs. All is well now it starts better than ever.