Switching back and forth from return/returnless

[03yllwguy]

I am stationed in CA and plan to go 2.9L G4 shortly BUT cannot decide return or returnless due to possibility of emissions (OBD II) within a few years.

Then it dawned on me, but I need a sanity check on this scenario:

If I have a deadheaded Lethal Budget Plus setup to stock rails, IF I had to pass emissions with a stock tune, could I reroute my feed line to the regulator direct to the fuel rails, then reroute my 12v inputs to the pumps from the Lethal harness over to a FPDM harness? This would function as a returnless system on a stock tune, and be easily converted back to return without changing my regulator setting and the only consequence would be quick connects built into the lethal harness to plug in and out of a FPDM harness?

Am I crazy or would this work? I know Walbro 465’s or equivalent are designed for return BUT I cannot find anything saying they wouldn’t function in a returnless long enough to clear all sensors.

Thoughts? I am ok if I have to pull the blower to swap injectors every few years (IF the smog guys don’t accept Whipples CARB EO which includes a tune), but not the tank every time.

 

[MG0h3]

Switching to return doesn’t throw any codes. Just don’t delete your Evap.


Sent from my iPhone using svtperformance.com

 

[01yellercobra]

Switching to return doesn’t throw any codes. Just don’t delete your Evap.


Sent from my iPhone using svtperformance.com

But not having the FPDM in place will cause other issues with the monitors being set. At least that's what I found when I looked into this a while ago.

OP, you can always wire the system up to keep the FPDM in place. That's how I did it originally following Malcolm's thread.

Or you can snag an FPDM plug from a crown vic I think it was. I have it plugged into the factory harness to power the relays for my pumps. If I wanted to I could unplug the relays and plug it right back into the FPDM.