Return line test question...

[Dallas S]

Lmm, doing a simple bottle test. With line ran off of main return at back of motor it will pour fuel out with motor off, while u push the primer on the filter housing. Normal? Trying to figure out a low rail issue...

 

[Burn Down]

Pretty sure the injectors return into that same line so you will get fuel out of it... I plugged the line with a plastic cap when I do the bottle test.

 

[Dallas S]

This is the main return that is going back to tank, injectors, fprv, and cp3 all feed into this line. With the engine off(not running), you can pump the primer on the filter head and fuel will pour out of the return. The primer never gets solid feeling either. Went and tested on my other truck and the primer will get solid, and after a couple min the return will start to drip.

I haven't been inside a cp3, but my best guess is some how the cp3 supply side is leaking into the return??

 

[Burn Down]

Yep sounds like the cp3 is bypassing...