1QWKC6A6

Ok guys have a few questions about fuel system. With your fuel systems do you use one or both of the LPE fuel pressure regulator plugs?

I have both installed and am having fuel pressure issues on initial startup, on cold start it does fine, after it is warm I have to crank it, switch off and crank again. My tuner says it cold starts fine because of ECM commanding more fuel on startup.

Most of the others I have spoken with only used the blockoff in the driver side tank and none are having this issue.

Also, my secondary Bosch pump has a check valve so this is not the issue.

Fuel pressure was good to 880 wheel so it does fine after it starts.

Considered doing another check valve for stock line just to see if it changed anything or not.

For reference here are links to the Blockoffs

http://www.lingenfelter.com/mm5/merc...3#.Urai_Z69KK0

http://www.lingenfelter.com/mm5/merc...3#.UraleJ69KK0

Thanks

Unreal

Longer cranks are normal when they are blocked off because the pressure will bleed off through the siphon system. Adding a check valve to the main line may help. To control the pressure with an AFPR you need to block both off. I don't know why anyone would just block one off.

turbotuner20v

if your base pressure will always be greater than 55psi to activate the siphon system between tanks, you could skip the passenger tank bypass.

and yes, longer cranks are normal. try just turning the key on to prime the stock pump if using it, then start.

gotjuice?

I run both on my setup. Maybe you damaged an O-ring when installed. My passenger tank blockoff was damaged and I had siphon issues. After O-ring was replaced all working great.

superchargedC7

If you have the fuel system apart you might as well install whatever makes you comfortable

1QWKC6A6

It isn't currently apart, that's why I'm trying to make a plan on how I want to approach it

chpmnsws6

Its probably very simple, but how do these work? I'm looking to lower base pressure and use a rising rate regulator, but would like to be able to use both tanks.

realcanuk

I have the blockoffs sitting in the garage and hesitate to install them because I keep seeing issues. Maybe when my tranny blows up and its easier to remove the tanks, I will attempt to install them. LOL