Return style fuel system.... New tune?

[03blwn281]

Hello,
I have a fox body with a terminator swap.
The vehicle has a 2.3 Whipple and all supporting mods.
Just recently switched from return less to return style.
My question is. If all I switched was fuel lines and rails
Do I need a new tune?

 

[TRBO VNM]

You need to explain more. There is no way you went from returnless to return by just switching fuel line and rails. If your car was tuned with returnless and you just went return with a return line, pumps, rails, regulator, then yes you need a new tune.

 

[03blwn281]

The car had twin 340 pumps on the return less set up. I will be more specific.
Fuel lines, rails, and regulator have been changed.
Your thoughts on a new tune?

 

[JUICEDL]

Yes, your gonna need a tune with the new fuel setup.

 

[badcobra]

No way around a retune after switching to return. All kinds of parameters will have to be adjusted in the tune.

 

[Swervedriver]

Yep it won't keep the fuel pump relays running full time for starters. If you hacked a way around that it'll throw all sorts of codes that would put the car in limp mode.

 

[MalcolmV8]

Yup like others said re tune for sure. Instead of the pumps been PWM by the ECU they will run at 100% power now and the regulator will bleed off the excess fuel.

Your tuner will adjust the fuel pump tables in your tune. Also be sure and set your base pressure on the regulator to what the tuner has put in the tune. Setting the base pressure to something random that doesn't match the tune can cause you some headaches too.

 

[03blwn281]

Thanks guys. Any insight on FPDM wiring?

 

[MalcolmV8]

Thanks guys. Any insight on FPDM wiring?

Well if you're going return and want to wire up your relays to be triggered by the FPDM so the pumps are still controlled by the ECU such as key on/engine off primes the pumps and then turns them off etc. Then here you go.

http://www.svtperformance.com/forum...how-allowing-oe-type-fuel-pump-actuation.html