6.7 very hard start

[scubieman]

I used my truck this morning to bring kids to day care then to work.When I started the truck at home it started fairly quick,When I went to leave daycare that thing had to crank and crank then finally after about 3-4 seconds in finally started.It does not do this everytime. No error codes I can see(check engine light is off) I never hooked the programmer up to read.

[scubieman]

One other thing. I have 8 to 11 psi fuel going into cp3.According to specs it is suppose to be 11.5.I have after market larger hose going from fuel filter to cp3. Unsure when it loses pressure it sucks air.

[IL6 Torque]

Welcome to my world only with an '07 5.9 . I'm not an expert but wouldn't the larger lines cause lower PSI while still allowing enough flow? I've read that cummin is more concerned with amount of flow and not about pressure. Mechanic explained to me yesterday about how the Cam Position Sensor signals interact with the Crank position sensor to tell the truck truck to fire. I'm sure the Guys alot smarter than me will chime in soon. :banghead:

[scubieman]

The larger line does not sense on start up. However once the volume is filled with fuel still only certain amount goes through pump whether hose is big or not.