Maybe two injectors bad, I isolated the worst #3 starts now. But look at what happen

[tichey327]

My truck was slowly losing power but drove OK. Then one day it wouldn't start no matter what, with out a little starting aid. So I checked the Cyl Balancing Floe Rates. I found #3 bad for sure and #6 a little weak. So I bought 2 fuel rail plugs to Isolate #3 then after that #6.
After I installed the fuel rail plug on #3 cylinder the truck would now start on it's own again, Yeah!!! So I do another cyl balance flow rate with that number 3 rail plug/cap still on the truck. Holy crap the flow rates went south on almost all of my other injectors!!! Even the ones the were spot on.

Please Guys give me some advice as what going on with my injectors.
As a side note I'm checking the flow rate at normal idle and normal idle fuel pressure. 10988

and after I blocked injector #3

10989


Thanks to everyone that helps me out on this

[tichey327]

check check

[tichey327]

here are the highlighted injector balance rate jpegs

10990

Before

10991


Thanks everyone!!!

[acrider2]

I'm assuming this is a LB7? my guess is that they are going negative to try and compensate for the dead cylinder. I would measure the fuel return on both banks and go from there. Do you have diesel in the oil?

[tichey327]

No. My oil is ok. before I blocked cylinder number 3 I could only get 700 Psi cranking. After blocking number 3 I can get enough pressure during cranking for it to start, but the crank times are a little long. I think I will go ahead and block number 6 and see how fast it builds cranking pressure. then see if I can get my max pressure above 11,000 Psi.

[tichey327]

OH, and yes it is a 2004 LB7 with a 140K miles. this is the first fuel/injector/pump problem I have ever had with it.