Is it possible?

[Electrickian]

Is it possible to change to a return style fuel system (from a 2002) on a '04-'07 truck that has a returnless system? If so, what would be involved besides having all the parts: injectors, rails, lines, pump, etc? PCM?

 

[mikez71]

Which '04-'07 trucks have a returnless system?
I looked at a few on charm.li, ('05, '06) and they were all return style..

 

[LsHart]

My 04 is a return. But my guys 06 silverado lm7 isnt

 

[LsHart]

And why would you want to?

 

[Electrickian]

I think '04 is when they changed. Maybe mid '04? Idk for sure. But I've read about the differences in the 2, and I'm more inclined to think return is better. I think GM went to returnless to save $. Cheaper for them and besides, what customer is gonna say: "This year model still using the return style fuel system, right?" Never. Did the sticker price go down? Lol

 

[LsHart]

So the 04 E85 system is top notch. If u wanna upgrade, that's the fuel system used. Filter on the back of the intake upgrade. It's 2 sides of the street type thing. What's good for u is what's better.

 

[Electrickian]

Which '04-'07 trucks have a returnless system?
I looked at a few on charm.li, ('05, '06) and they were all return style..

04-07 Tahoe

 

[j91z28d1]

I think '04 is when they changed. Maybe mid '04? Idk for sure. But I've read about the differences in the 2, and I'm more inclined to think return is better. I think GM went to returnless to save $. Cheaper for them and besides, what customer is gonna say: "This year model still using the return style fuel system, right?" Never. Did the sticker price go down? Lol

in the Tahoe it's like 08 and up or something around there is returnless. I see posts from guys on here wondering why the fuel pump relay is missing on the newer ones, but there on the 07.

either way, returnless is not cheaper in any way for gm. there's an entire module for the pump, extra fuel pressure sensors. which is actually better is hard to say. my return less has 180k on the oem pump, so I doubt it shortens pump life. the return style can be cheaper if you go boosted to add a boost reference fuel pressure regulator. but with hptuners you can unlock the fuel pump module and a good tuner can adjust the settings in it for boost too. so eh. toss up, just repair what you have.


oh there's 2 kinds of returnless gm used, the older ones like in camaros and corvette just had the fuel pressure regulator in the fuel tank, or back by it. one gm used looked like a fuel filter, but had a 3rd return line in it. mounted at the back and then just one pressure line ran to the front it wasn't actually returnless, but could seem like it it's still mechanial, just not up on the fuel rail. the real returnless has a module that controls the fuel pump speed using a PWM 0-12v square wave it's a true dead head, with no return. with those types you can see a lot of live data on the scan tool, things like fuel pressure requested, actual. fuel trim, which might help you see a failing fuel pump. as it needs to trim the duty cycle much longer than normal to hit the same psi on a failing pump.

 

[mikez71]

So the 04 E85 system is top notch. If u wanna upgrade, that's the fuel system used. Filter on the back of the intake upgrade. It's 2 sides of the street type thing. What's good for u is what's better.

And I heard E85 setups have higher flowing injectors...

 

[Marky Dissod]

And I know for a fact that E85 setups have higher flowing injectors ...

E85 5.3L LH9, 6.0L L96, or 6.2L L94 injectors flow 37lb/hr, 50lb/hr, and 54lb/hr respectively.
Most who try to buy injectors cheaper than GM OE wind up buying one of the cited GM OE sets anyway.

 

[donjetman]

My 2002 LS1 Corvette has what they call a "fuel filter/regulator".
On the south end of it there is an inlet and an outlet to/from the fuel tank/pump.
On the north end of it is one outlet to the engine.
NAPA Gold #3737, same as GM# 19239926 or ACDelco# GF822

 

[j91z28d1]

My 2002 LS1 Corvette has what they call a "fuel filter/regulator".
On the south end of it there is an inlet and an outlet to/from the fuel tank/pump.
On the north end of it is one outlet to the engine.
NAPA Gold #3737, same as GM# 19239926 or ACDelco# GF822
View attachment 482406

yes, this thing.

it's kinda works like a returnless system by having only one fuel line run to the injector rail. but really it's just a regulator mounted in the back and takes place of the old school inline fuel filter. even though I believe it has a filter in it too.

a true returnless of the newer vehicles have no mechanical fuel pressure regulator anywhere in the system.

 

[hagar]

Just need a return style fuel system, then your stock computer has a switch in it that can be set to return style fuel pump instead of variable voltage return less. Set that switch to constant voltage return style, and you are good to go.

 

[RET423]

If it uses the corvette style filter/regulator then you replace that with a regular fuel filter, extend the return line up to the engine compartment, get a set of fuel rails off of an 01 with the regulator in the rail, install that rail & hook the return port to the line you ran from the old filter to the engine compartment and your old pressure line to the pressure side

No tuning needed if it had the corvette style system

 

[LsHart]

And I heard E85 setups have higher flowing injectors...

I was blessed with this setup. It has all the bells and whistles. Came across this rig through a family friend.

 

[LsHart]

Return is key. U can do more with the return style. In my eyes.

 

[Electrickian]

Just need a return style fuel system, then your stock computer has a switch in it that can be set to return style fuel pump instead of variable voltage return less. Set that switch to constant voltage return style, and you are good to go.

And there it is: the answer I've been looking for all along. Thank you hagar. I feel like I kinda owe you now lol