Corvette Regulator with a stock 5.3 return line Fuel rail

[daveshilling]

Okay yall, so I messed up. Help me figure out the overall best move here:

I bought a Tanks, Inc tank over the phone and they were like "You want the fuel install kit" and I said yes... but only later.. AFTER cutting lines, installing fittings, installing the Vette Regulator/filter.. did I see its for returnless rails only.

What I need to choose between:


Approach 1: Keep the return style rails, and:

Ditch the vette regulator and buy a filter instead: $30 for the filter, will probably resell the vette regulator and make $20? net $10

Buy 10 more feel of Russell Twist Lok fuel line - $50

Buy an AN-6 male-to male adapter, another twist Lok fitting, and another QC for the return rail to extend the return line I've already cut to length (makes the tank easier to remove anyways) - $30

I've spent $90 extra, I have a frame mounted filter, and I have a return line, which the engine is designed for and I assume the PCM is expecting.


Approach 2: Swap out the return style rail for a returnless rail

Cost:? will a later year 5.3 returnless line work okay? Will it even fit? Are the injector plugs different? Are the injectors different? Will the PCM be displeased?

I've seen anywhere from "Ditch the vette piece, run a return line/Just plug the return, its fiiiiiine (no)/Buy a returnless billet piece from eBay/ etc"

The $90 and be done with the research option looks good, but if I can swap the rails with no drama, that might be cheaper and better!

[LS short box]

So my .02 and I may be all wet. If can find a good way to plug the return side of the fuel rail that seems like a good way and least expensive way to go. If you use the C5 FPR and use it's return port back to the tank the fuel rail will only see 58 psi. The PCM has no clue what the fuel pressure is and doesn't care as long it's 58 psi.
Not knowing the year of you 5.3 I think the injectors stay the same for a number of years but after 2006? the injectors changed because the electrical connectors changed and the length of the injectors?
Check with the folks over on LS1tech. I'm sure they can help.

[mongocanfly]

That's exactly what I did..plug the return fitting on the rail...I used a pushlok to -an...then a -an cap on that..I stuck with the vett filter/reg..been holding for over 20,000 miles with no issues

[ls1nova71]

Originally Posted by LS short box

The PCM has no clue what the fuel pressure is and doesn't care as long it's 58 psi.

True, to an extent, however, the fuel maps are different between a set 58psi and a vacuum regulated 58psi. so you need to adjust for it in the tune for it to be right. That said, the vacuum regulated return style is actually a better system, but the corvette set 58psi is just a little simpler. If you already have a return rail, i would just run it that way and use the cheaper filter. If you insist on going returnless. do yourself a favor and just grab a returnless set of rails from the junkyard and skip trying to plug off the return line. I know people do it, but its just a potential spot for trouble in my opinion.

[daveshilling]

20,000 miles ain't bad... I could definitely just get a $5 cap and see how it runs I guess. It wouldn't be a considerable effort to run a return line after the fact if that fails. I probably wont even drive this truck 20,000 miles in 5-10 years.

I have a 2003 5.3. I've seen posts on LS1Tech and havent found anything definitive about fitment, although I've seen some folks saying they swapped out for returnless rails and had to make custom brackets and such.

LS1Nova, I applaud your consistency, I found a post from 2012 where you recommended running a return, both here and on LS1Tech!

I couldn't find anything definitive saying what rails will fit... flexfuel rails apparently will, but then i need to deal with new longer injectors, and TBSS rails were mentioned but they cost more than $90. Pick n pulls out here are picked and pulled before I get there, so it looks like I try the $5 cap. If it sucks eggs, I do the $90 return line.

[ls1nova71]

Returnlrss rails will fit as long as they come from another truck engine. The injectors are different from flex and non flex and return style rails are flex and non flex specific. If you're going to go the returnless route, those rails are cheap, but I guess if you can't find any in the yards around you that makes it a little more difficult, however, keep in mind, if the plug you cap the rails with fails, it will likely leak fuel on a hot engine. Also, you need to remove and plug the regulator, when those fail they leak fuel too, only you generally don't notice it because the vacuum hose sucks it into the intake, but it you do notice it running bad.

[derotoreut]

I used ls1nova's advice on the fuel rails for my build. I went with returnless rails from another truck engine. They fit right in and got rid of the regulator on the rail. Great advice and easy to do.

[daveshilling]

Originally Posted by derotoreut

I used ls1nova's advice on the fuel rails for my build. I went with returnless rails from another truck engine. They fit right in and got rid of the regulator on the rail. Great advice and easy to do.

If I can find a reasonably priced set, I will probably take that approach... cant have fuel leaking out!

[Pitpig]

I simply ran a -6 return line to the tank from the intake fuel regulator like it was designed. Hard lines would have been cheaper

[chev-obsession]

Originally Posted by derotoreut

I used ls1nova's advice on the fuel rails for my build. I went with returnless rails from another truck engine. They fit right in and got rid of the regulator on the rail. Great advice and easy to do.

Agreed! Simpler and cleaner in my opinion

[rodstored-72]

well I am in the same boat with my current build. I have a 2013 return type engine and I have just installed a "corvette style" filter/regulator. I am wondering as opposed to re-doing my setup, can I just run the engine return line and "tee" it into the return line side at the filter/regulator? also if I understand right then my return lines can be the F.I. hose with F.I. hose clamps ("Tee clamps) and can just be clamped over the steel line nipples?

[mongocanfly]

My C30 is also a return rail, and i run a vett reg/filter..what I did was use a qd to -an on the return fitting on the rails..and then put a -an cap on it..
I know it's not the preferred method , but it works..being working for over 10yrs and 20k miles now..
No need to tee them together..
You could also swap to a returnless rail..

[rodstored-72]

mongo, thanks for the reply, as above if I understand then I can just cap that line off at the engine rail?

[mongocanfly]

Yes...but be sure to use the push lock to -an , and a -an cap...

[rodstored-72]

mongo, 10-4.. I was thinking the same, thanks again!!!

just curious though... I guess in doing the "cap" proceedure does not add any additional "pressure/back pressure" inside the fuel rail/engine system???

[mongocanfly]

I've had no issues...Ive got a gauge on my fuel rail and I havnt seen anything excessive..the vett reg takes care of it..

[mongocanfly]

here you go rodstored
this is what i used...or similar under a diff name

https://www.summitracing.com/parts/rus-640863

https://www.summitracing.com/parts/sum-220640b

[dec010974]

Wow. There are so many ways to skin a cat.

[rodstored-72]

Mongo, thank you! I appreciate the reply. that is exactly what I was thinking you did. I will order/get those fittings and do the same thing. I took the line off from the engine side last night as well as removed the steel line from underside . man! the first clamp was a PITA to "open" to remove the line...

[LS short box]

Just quick note the fuel rail fitting that Mongo used has been updated to include a retaining nut so the the fuel rail fitting cannot come off the fuel rail by accident.
Note to Mongo. I know you haven't had any issues but I would safety wire that fuel rail fitting can't back off if the plastic retainer fails.

[mongocanfly]

Were the pushlocks coming loose?...with the millions of them that were used, I've not heard of any issues with them coming loose....not saying they wont...anything can fail...and it would be a bad day if it did..

[rodstored-72]

Originally Posted by LS short box

Just quick note the fuel rail fitting that Mongo used has been updated to include a retaining nut so the the fuel rail fitting cannot come off the fuel rail by accident.
Note to Mongo. I know you haven't had any issues but I would safety wire that fuel rail fitting can't back off if the plastic retainer fails.

hhmmm... interesting, I was trying to use a fragola "quick connect" fitting on the factory return line (at engine) & it would not "connect", it seemed like the fitting housing was too long for it to "lock" onto the factory rail line - rail line was a shorter "nipple" than the fitting?? so I am just using the factory fitting (with plastic tube) and hose fitting back to the cap.

[rodstored-72]

well I did what Mongo indicated, I capped off the return line at the engine side. I did use a portion of the factory line. I cut the plastic and added a hose (fitting) at end with a cap.

[ls1nova71]

Originally Posted by rodstored-72

well I did what Mongo indicated, I capped off the return line at the engine side. I did use a portion of the factory line. I cut the plastic and added a hose (fitting) at end with a cap.

Can you post a pic of this? I try and not comment on this any more because of conflicting ideas, but what you say you have done doesn't sound super safe, at least the way you worded it.

[mongocanfly]

I'm with Eric...something dont sound right about that...
You shouldnt have any plastic line..the pushlock snaps onto ths metal return rail..the cap goes on the -an pushlock

Nothing against Eric, absolutely nothing,,,,nothing but respect..hes helped many a member thru alot of issues
but I know he doesnt like the way I did mine..but I did mine way before I ever found the 67-72 site..what I did was recommended by a LS swap guy...its been holding for yrs and miles..
The way he would recommend, I'm sure , is to swap to a returnless rail,, which I might have done back in the day if I'd known it was a option..but I just didnt know back then..