2007 6.0 stalls while driving

[aparise72]

I have a 2007 6.0 that stalls while driving. I verified the concern. Had no codes. Checked fuel pressure at the secondary fuel filter. I have 30psi at idle with the valve closed on the tester. I open the valve and it drops down to 26psi. The truck has new filters. I replaced the fuel pump and retested and still have low fuel pressure. Now if I plug the return line between the conditioning module and the secondary fuel filter I have good fuel pressure. Anybody have any ideas? Could this be an issue with the fuel pressure regulator spring? Thanks, Andy

[lmorris]

Always change the regulator spring first. That is most likely to cause low pressure. When the pumps fail you get no pressure at all and it sets the fuel pump circuit open code.

[aparise72]

I pulled the regulator spring and it looks a little chewed up on the end against the cover. Thanks for the help, Andy 

[Matt Saunoras]

The new blue spring you'll get is actually an upgraded part. With a good HFCM it'll typically push the pressure at idle into the 60s

[Alex Bruene]

I was resealing a leaking regulator last week...  I always replace the spring too, not just the seal.  I was showing my apprentice the difference.  We measured 55 psi with the old spring, and 70 psi with the blue spring.

[amailloux]

_{This may have been covered before, but just the other day the superstar tech said to never upgrade the spring on old injectors as the 15 psi increase blows the O-rings out.  I have been putting them in with no issues.}

[aparise72]

I replaced the regulator spring and truck runs great. The customer is happy and now he wants us to do head studs to it. More work for me I guess!

[Aaron]

_{This may have been covered before, but just the other day the superstar tech said to never upgrade the spring on old injectors as the 15 psi increase blows the O-rings out. I have been putting them in with no issues.}

I think "you'll need 8 injectors and a regulator to fix the low fuel pressure" would go over like a fart in church.