LB7: Kinked fuel return lines and no fuel cooler!!!

[Stevenmc89]

He's a good friend of mine from my old forum days that has been fallowing this problem. I've been all over the fuel lines to. Only thing left is to hook a vacuum pump up and pull a vacuum. If the lines were a problem I would think my desired vs actual would be off? The desired vs actual is good threw all rpms so I think it's not commanding enough fuel? Maybe the app sensor not showing the amount of throttle being applied correctly? If I had a list of sensors that control stuff like that I would just start throwing parts at the damn thing!!!

 

[Aaron@LDS]

Steve, I can't remember if you ever changed the CP3 on that thing? What is your rail pressure maxing out at? Command and actual.

 

[Stevenmc89]

Cp3 was changed in June due to it was weak and causing limp mode and only letting me get 2000 rpms. I don't remember what the desired fuel pressure was but I remember it got no where close to the 23k they say it is suppose to get at WOT so I'm thinking its not commanding enough

 

[dracing70]

Like I said before. I have this same exact issue with my lb7. My suspicion had always been my return line. I have never changed it cause it runs ok and gets great mileage. But like I said one day out of nowhere something changed and it did not smoke as much or have as much power. Iv changed everything on this truck including engine. All but return and supply lines. Let me know what u find.

 

[Stevenmc89]

If I ever find out what it is I'll let you know. Like you, I can get around on it if I have the edge turned all the way up and it gets good mileage to. I don't know what it could be and every shop I've been to has been stumped also