Quote Originally Posted by Rees Guide View Post
What I said first time I heard this. 7.3s and apparently 6.0s fuel injection is run off of oil pressure. Low oil pressure and they wont crank or run, bad orings around the injectors will cause a miss as the cylinder will not get any fuel. Its a strange design but a very efficent one and it is a protective one, you can't run em out of oil, they will quit due to lack of oil pressure and still have 7 or so quarts of oil in them. Also, if you go too long between oil changes and the oil breaks down you lose performance because of a lower oil pressure. 7.3 powerstroke without oil pressure is scrapmetal!!!

Yep they are both HEUI versus common rail on 6.7
On the heui any hpo (high pressure oil) ) leak will cause no start, bad running, etc. And Feelay is correct---the 6.7 is a beast.