LC9 Confusion

[1966Stepside]

So I'm checking out my '06 5.3/4l60 I picked up, and it looks like it has a return line on the fuel rail. I'm a bit confused by that, since I was under the impression that starting in '03 or thereabouts the fuel rails switched from having a return to not having one. Can anyone clarify?

Also, do all of the LC9s have VVT and AFM?

[Clyde65]

Van's had return rails until 06 model year. You could have a van motor ( it's not a bad thing) did you get the VIN from the yard you got it from?

What is an LC9?

[1966Stepside]

Nah, it's out of a Silverado. I got the VIN, but I've misplaced it somewhere....

LC9 is the Flex Fuel version of the LH6. Just another code for a Gen 4 5.3

[Clyde65]

Oh, ok, I didnt know they had a "cods" for them. I think the injectors are just bigger on them right?

[usmcchevy]

If you got the PCM your tuner can pull the VIN out of it. Maybe the flexfuel had a return, you sure its not the EVAP line?

[Goats86]

my 5.3 is a 2003 non flex fuel out of a Silverado. It has the return lime to the tank

[usmcchevy]

Returnless started in 04, with the vans in 06.

[clinebarger]

Returnless started in 04 for trucks, I have 2 truck 5.3s both are returnless.

[usmcchevy]

Originally Posted by clinebarger

Returnless started in 04 for trucks, I have 2 truck 5.3s both are returnless.

Oops, I'm loosing it today I'll edit my post, thanks

[1966Stepside]

Originally Posted by usmcchevy

If you got the PCM your tuner can pull the VIN out of it. Maybe the flexfuel had a return, you sure its not the EVAP line?

Newbie question, what's an EVAP line? When I google that all I get is stuff about pregnancy tests.

Maybe my engine is pregnant! I'll have a little 4-banger running around the shop

[usmcchevy]

Lol, Evaporative emission system. Should be a solenoid that looks kinda like this on the top of the intake.



It can be removed, I plugged mine with a 1/4 or 3/8" NPT plug.

[clinebarger]

Originally Posted by 1966Stepside

So I'm checking out my '06 5.3/4l60 I picked up, and it looks like it has a return line on the fuel rail. I'm a bit confused by that, since I was under the impression that starting in '03 or thereabouts the fuel rails switched from having a return to not having one. Can anyone clarify?

Also, do all of the LC9s have VVT and AFM?

A 06 FlexFuel 5.3L would be a Gen III L59, Gen IV LC9s didnt come out untill 07 in NBS Silverados.
Did you find the VIN, Were all confused on what you have.

Heres a pic of a 06 FlexFuel L59, Notice the returnless stainless steel fuel rails V.S. plastic on a regular LM7 5.3

[1966Stepside]

No, can't find the VIN. You know how it is, you write it on a piece of paper and then the paper decides to disappear... The guy I got it from still has the cab, so getting it again is no issue.

Here are a couple shots of the engine. None from the "perfect" angle, though.





They are definitely stainless lines, and there are definitely two of them. Wish the engine was here with me, but it's at the shop a few miles away. Not sure if you can tell much from them, other than my shop needs cleaning.

I was doing some quick research here:http://www.pirate4x4.com/tech/billav...SPrimer/Part2/

found the link in the LS swap FAQ. I didn't see a Flex Fuel Gen III, but I'll take your word for it. I wasn't particularly wanting the VVT and AFM.

It's definitely '06, and definitely 5.3, and also Flex Fuel, so it looks like it's a L59 then. Guess that explains why I can't figure this thing out.

[clinebarger]

Its returnless, White circle...Supply line. Yellow circle...Evaporative emissions supply line to the purge solenoid (the solenoid in usmcchevys post) , A return system would have 3 lines going to the engine in factory form.
Looks like you got a pretty complete engine/trans combo, Do you have the pedal & TAC module?

[1966Stepside]

Don't have the pedal yet, but the donor vehicle is still available to get it out of, and it's included in the price. I wasn't in a big hurry to get it, since I'll just be using the engine to do test fittings for a while. I believe the TAC is dangling off the side of the engine to the left of your circles. Other than that, it's fully complete. Even got the AC compressor. Guy I got it from is the same guy doing the body work, and he's given me free reign to grab anything from the gas tank forward for the engine. The rest of the truck is either trashed or already been salvaged. I've been reading trying to figure out if i can get the pump to fit inside the tank I have on the way from LMC. Might just have to grab it and see.

[1966Stepside]

Finally found my vin, it's an L59!