LLY: fuel line issues

valleyduramax

Member
Jul 25, 2010
233
4
18
Ottawa ON Canada
i had posted a few weeks ago about having a no start issue after doing some mods to the old lly. Well i got it figured out and it was all due to a few leaking fittings at the filter heads for my new lift pump/filter system i made up. Got them all sealed up and seems to work ok. but i still have to crank truck for quite a while before it fires and once it fires it runs great. I deleted the stock filter and test port. So my question is, is there a check valve in the test port or stock filter head that stops the low pressure feed line to not lose pressure or is it possible that i have another leak somewhere in my feed line?????
 

Burn Down

Hotrodder
Sep 14, 2008
7,092
28
48
Boise Idaho
There is no check valve that i'm aware of. My stock filter head is gone as well & I have no issues with starting. If you have a lift pump applying positive pressure to the cp3 I doubt its a fuel starvation issue... Fill out your signature so we no what your working with.
 

valleyduramax

Member
Jul 25, 2010
233
4
18
Ottawa ON Canada
I have a dual filter system i built with an Aeromotive 1000 pump and return style regulator plumbed direct to CP3. I used compression fittings and push lock fittings and stainless tube throughout. I think the system may be loosing prime after the regulator as i have 2 compression fittings mated to some pushlock fittings but used regular teflon tape instead of sealent or fuel rated teflon tape as i didnt have any at that exact time. I well tear it apart and reseal those connections and go from there. hope it fixes it
 

Burn Down

Hotrodder
Sep 14, 2008
7,092
28
48
Boise Idaho
Are the fittings leaking? They should be under pressure anytime the key is in the run position & the lift pump is on. What pressure is your lift pump set at?