I have seen the impossible!

[duratothemax]

swapping an LLY or LBZ into an 03-04 LB7 is SOO easy.

An LLY into an 03-04 LB7 is literally 100% plug and play. If you can unplug and re-plug in some harnesses, you can do the swap.

An LBZ into an 03-04 LB7 is 98% plug and play. You plug everything in, then run like 3 extra wires from the ECM into the cab for the GMLAN +, GMLAN -, and driver shift request wires (IE, tapshift).

And you have to move a couple pins around in one of the connectors under the fuse box. But honestly, it would probably only take another hour or two from what it would take to swap an LLY.

LLY or LBZ into an 01-02 LB7, forget it.

 

[WisconsinHick1]

Ok so I am looking into getting LLY top end parts to do this swap. If anyone knows who has a LLY motor willing to part with the top side I would appreciate it.

Now what is involved with the wiring for the injectors is where I am lost. Will I need to make wires from the FICM to the injectors? The rest doesn't sound bad just swapping out the top half of the motor. Heads, fuel rail, injector feed lines, ect.

 

[MACKIN]

Ben


What do you mean 01-02 forget it? Obviously it can be done as shown here or are you saying cost? Guys with a 03-04 should be all over this like stink on poop! Plug and play? Doesn't get easier than that.

 

[cole30]

swapping an LLY or LBZ into an 03-04 LB7 is SOO easy.

An LLY into an 03-04 LB7 is literally 100% plug and play. If you can unplug and re-plug in some harnesses, you can do the swap.

An LBZ into an 03-04 LB7 is 98% plug and play. You plug everything in, then run like 3 extra wires from the ECM into the cab for the GMLAN +, GMLAN -, and driver shift request wires (IE, tapshift).

And you have to move a couple pins around in one of the connectors under the fuse box. But honestly, it would probably only take another hour or two from what it would take to swap an LLY.

LLY or LBZ into an 01-02 LB7, forget it.

Interesting!

 

[duratothemax]

Ben


What do you mean 01-02 forget it? Obviously it can be done as shown here or are you saying cost? Guys with a 03-04 should be all over this like stink on poop! Plug and play? Doesn't get easier than that.

To swap a "complete" LLY or LBZ (ECM and all) into an 01-02 would be a nightmare of wiring.

However you can make the "hybrid" setup (LLY injectors driven by the LB7 ECM) as shown here and the wiring will only be about half as bad...still kind of a PITA though, and you have to play around with tuning a bit to make the LB7 ECM work properly with the [smaller] LLY injectors.

If I had an 03-04 LB7, I would definitely do the LLY swap. If you look around and find parts cheap, you could probably do it all for around 3k, provided you did all the labor and stuff yourself.

 

[MACKIN]

To swap a "complete" LLY or LBZ (ECM and all) into an 01-02 would be a nightmare of wiring.

However you can make the "hybrid" setup (LLY injectors driven by the LB7 ECM) as shown here and the wiring will only be about half as bad...still kind of a PITA though, and you have to play around with tuning a bit to make the LB7 ECM work properly with the [smaller] LLY injectors.

If I had an 03-04 LB7, I would definitely do the LLY swap. If you look around and find parts cheap, you could probably do it all for around 3k, provided you did all the labor and stuff yourself.

Ok understandable. I hear you on the wiring reading Hawk's post he makes it sound easy but I can only imagine it is more difficult to actually do unless your real familiar with it. I look at the mass of wiring and it is no joke. I cannot even figure out how to disconnect the FICM! (Just kidding I never attempted)

IMO piecing it out MAYBE if you get a set of good injectors with the LLY heads it can be done for 4/5000 worth it to put the injector issue to bed but it is no easy job IMO. I'd probably buy a new truck. :roflmao:

 

[cole30]

Lbz is more work (not plug n play like an Lly) but possible. I have a write up with PN#'s if you want to go that route.

Sure I will take them if you got them... I got to do some studying.

 

[juddski88]

Ok understandable. I hear you on the wiring reading Hawk's post he makes it sound easy but I can only imagine it is more difficult to actually do unless your real familiar with it. I look at the mass of wiring and it is no joke. I cannot even figure out how to disconnect the FICM! (Just kidding I never attempted)

IMO piecing it out MAYBE if you get a set of good injectors with the LLY heads it can be done for 4/5000 worth it to put the injector issue to bed but it is no easy job IMO. I'd probably buy a new truck. :roflmao:

The FICM Wiring was not even close to being as bad as the ECM and TCM relocation. And as I said before, and as Ben pondered while helping me with my build, an LLY FICM should work just the same. The data bus just are named differently from what we could tell, they should still carry the same type of signal.

 

[MACKIN]

Not familiar with the underhood on a LLY are you implying that a relocation of ECM and TCM is necessary or is this something you did for other reasons? The reason I ask is Hawk posted that the only wiring besides the fuel pressure sensor was at the FICM.

 

[THEFERMANATOR]

The FICM Wiring was not even close to being as bad as the ECM and TCM relocation. And as I said before, and as Ben pondered while helping me with my build, an LLY FICM should work just the same. The data bus just are named differently from what we could tell, they should still carry the same type of signal.

The origanal poster here said he tried this and the LB7 ECM would not talk to the LLY FICM, this is why he said he went back to an LB7 FICM and made the hybrid harness.

 

[THEFERMANATOR]

Not familiar with the underhood on a LLY are you implying that a relocation of ECM and TCM is necessary or is this something you did for other reasons? The reason I ask is Hawk posted that the only wiring besides the fuel pressure sensor was at the FICM.

There's 2 completely differrent kinds of swaps being discussed here, so it is causing some confusion. The thread starter talked about swapping an LLY top end to an 01-02 LB7. This involved swapping the heads and LLY fuel system over and making a hybrid wiring harness to connect the LLY injectors to the LB7 FICM to trigger them. Then there is the 03-04 LB7 swap where basically you are converting the LB7 to an LLY or LBZ. This method involves removing the LB7 controls and swapping in the later model control system and matching engine components. The LLY ECM mounts differently than the LB7, so this is where I believe they are talking about the relocation of the ECM and TCM.

 

[duratothemax]

Not familiar with the underhood on a LLY are you implying that a relocation of ECM and TCM is necessary or is this something you did for other reasons?

He did it because he likes seeing me go insane and lose even more hair when working on his truck. :

You dont have to at all, Juddski did it to clean up the underhood area

 

[MACKIN]

Got it thanks for the clarifications.

 

[juddski88]

I still used the LB7 ecm, I relocated them to make room for working under the hood, and to keep the electronics cooler

 

[juddski88]

The origanal poster here said he tried this and the LB7 ECM would not talk to the LLY FICM, this is why he said he went back to an LB7 FICM and made the hybrid harness.

I know he said he tried it, but he might've had just one little thing wrong and it wouldn't work. I had a few of those "little things" where it was mind boggling as to how simple the fix was ( swapping the ECM AND TCM connector covers by accident) (loose FICM Engine Speed Signal pin in the C1 that was causing P0374 code and no start).

A loose pin like I had could cause his issue with the LLY FICM and go totally unnoticed. It took me weeks of checking the harness, continuity testing, replacing CKP and CMP sensors, etc and Ben and Schulte's help with thinking of what it could be and testing ideas to finally find it.

And to be honest, the wiring, the fabricating, all of it doesn't hold a candle to how frustrated the MITUSA pump has made me.

 

[juddski88]

there's no way it should cost that much! Heck, you can buy complete LLY with harnesses all day long for less than that, swap it out for yours, make the wiring changes needed to run the LLY with the LB7 wiring and sell the stuff you swap out or don't use. I'd say you could do it for half of that estimate which is on par for having a shop replace the injectors in an LB7 I'd say.

Yea, like I said, it only cost me that much because my heads are Stage 2 heads, my injectors are ~34 LPM injectors, etc.

and as far as the harness goes, for my truck we deleted the fuel filter wiring, the VVT wiring, EGR wiring, pass side battery cables, spliced in the LB7 GPCM, CKP and CMP wires, oil temp and level harness, and LB7 FICM connectors. I think that was it IIRC. I now can delete the AC wiring too I guess.

 

[RPM Motorsports]

. No one has put a actual dollar amount on this swap even a DIY'er. Eventually someone will.

Only three in this thread , Hawk355,bdubu1986 and juddski88 , have done it and haven't put a number on it. None of these probably will either. Hawks not here much as bdubu isn't and he didn't even respond to Trippen's question. Judd did a bunch of work besides this so it might be difficult to put a actual on it.
.

I do the 03 LB7/LLY swap's starting around $6800, and LB7/LBZ starting at $8k. Almost done with an 01 to LBZ/HTT68, so I don't have a total yet. Prices depend on milage on the motors i supply and include fluids, 6mo. Warrantee, install ect. I deal with four yards that buy grade "A" motors for me.

 

[Maricopaagent]

So whats the ideal combo?

lbz rods
lb7 pistons
lly heads

 

[SmokeShow]

Its been a little bit since I read through the details of exactly what was done for the LLY in the 01-02 but in a nutshell it's really a complete LLY (the short block is the same as LB7 so there's no sense swapping the top ends and fuel system, just swap in a complete LLY engine) bolted in and then splice the proper connections from the LLY harness into the LB7 harness so it plugs into the LLY injectors, sensors etc., right? Still use the LB7 control modules - ECM, TCM and FICM to fully run the LLY components, right?

 

[duramax3388]

Its been a little bit since I read through the details of exactly what was done for the LLY in the 01-02 but in a nutshell it's really a complete LLY (the short block is the same as LB7 so there's no sense swapping the top ends and fuel system, just swap in a complete LLY engine) bolted in and then splice the proper connections from the LLY harness into the LB7 harness so it plugs into the LLY injectors, sensors etc., right? Still use the LB7 control modules - ECM, TCM and FICM to fully run the LLY components, right?

Yep just switch out the turbo and go for it but if your this far in might as well put a s366 or something like that no use in going back to a IHI.