I have seen the impossible!

Pure Diesel

Active member
Apr 22, 2008
871
129
43
Ventura County
The LLY swap is not going to be cheap either.
Yea, but think about this for the long run. Even if this costs the same as a complete injector replacement, the ease of repairs in the future. O.K. an injector happens to go bad. You can diagnose which one it is and replace it easier. You can't do this this easy on the lb7. I hope I don't have to do this conversion to soon, but you never know when, but I'm looking forward to seeing the details about this.:D
 

Pure Diesel

Active member
Apr 22, 2008
871
129
43
Ventura County
Ok, this is my truck we are talking about here.

For starters I would like everyone to know that this thread should NOT be about weather or not it can be done, or why one would want to do it, but more "how it was done".

I’ll try to answer some of the simple question now but I don’t have time to go into details at the moment. I will look for the procedures that I wrote up (over a year ago) later this week. Along with posting a few pictures.

I have 35,000 miles currently on this dyno proven 600rwhp daily driver to back up all of my statements.

For those that WONDER WHY: My injectors failed at 160,000 miles and they replaced all of the fuel lines on top of the engine including the fuel rails due to corrosion. This time was under warrenty and it would have cost me over $3,800 if it hadn't been. So if I had put another 160,000 miles or so on the engine they would probably have failed again. But the engine didn’t make it that far, long story short it locked up 25,000 miles later. The block and pistons were scared really badly and I wanted to get the injectors out from under my valve covers for ease of access and safety. The LLY has dry injector cups witch means there is no coolant surrounding the injectors that can leak into the cylinders (this was the cause of my LB7s failure).

1. This LLY is setup like a LB7, NO EGR OR EGR COOLER!!! AND NO VVT

2. I’m using the stock LB7 ECM and FICM

3. The voltage and wire location between the two computers are identical from 2001 to at least 2005

4. The voltage to the Injectors may be different. This is why I’m using the FICM from a LLY (A Bosch engineer told me that all of the injectors that they supply to GM run off of a 12v supply line. He also told me that this engine would never run in my truck! 5 minutes after I got off of the phone with him the truck was running!!)

5. I spent more time studying the wire diagrams on the LB7 and LLY then the time it actually took me to install the engine.

Again I will post the detail later this week when I have time.

The Diesel shop, that I buy from and have work done to my truck, had the same theory of the cooling around the injectors as the cause for failure. He doesn't believe the voltage is the problem. Its the cooling and heating cycles.
 
Last edited by a moderator:

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,341
1,623
113
Mid Michigan
Yea, but think about this for the long run. Even if this costs the same as a complete injector replacement, the ease of repairs in the future. O.K. an injector happens to go bad. You can diagnose which one it is and replace it easier. You can't do this this easy on the lb7. I hope I don't have to do this conversion to soon, but you never know when, but I'm looking forward to seeing the details about this.:D

Thankyou....you understood where I was coming from! Neat part is, you shouldnt have the O/H issues that are typical LLY fare, either
 

05smoker

I'm officially done!
Mar 30, 2007
2,379
0
36
Lebanon, OH
Yea, but think about this for the long run. Even if this costs the same as a complete injector replacement, the ease of repairs in the future. O.K. an injector happens to go bad. You can diagnose which one it is and replace it easier. You can't do this this easy on the lb7. I hope I don't have to do this conversion to soon, but you never know when, but I'm looking forward to seeing the details about this.:D

I understand all your points about the advantages of the LLY and the exposed injectors and I agree. My point was the cost and work would be significantly more. If you are paying someone to do it, price a head gasket job to start with and see where that puts you. Then get the heads, injectors, FICM, etc off a donor LLY and see where you are at. Pulling the heads off an LB7 is not a fun job.

I have to replace the heads on my pulling motor and this thread has caught my eye. My motor will already be out and I have some other parts to do some trading with so I am interested in more details, plus I'm tired of injectors cups, head gaskets and bad LB7 injectors just like all of you. I just don't think this is as easy and affordable as some of you guys are looking at IMO.
 

Hawk355

New member
Feb 26, 2008
14
0
0
I made a mistake on my previous post; I'll try to edit it to prevent confution for future viewers.

I'm using the LB7 ECM and FICM. I tried using the LLY FICM at first but I was unable to get the computers to comunicate using EFI Live. This is when I called Bosch and talked to an engineer to confirm that I would not burn up the injectors by using the LB7 FICM.

As for the different injector voltage numbers for the LB7, LLY, LBZ and LMM I've seen these numbers talked about in many different places, but only on message boards. Can we trace this information back to an original source, maybe a GM approved document?

I've found the procedure that I had written up last year, but its missing some part numbers, so please be patient while I look for this information.
 
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Mike

hmmm....
Feb 17, 2007
2,184
0
36
San Angelo, TX
Ok, this is my truck we are talking about here.

For starters I would like everyone to know that this thread should NOT be about weather or not it can be done, or why one would want to do it, but more "how it was done".

I’ll try to answer some of the simple question now but I don’t have time to go into details at the moment. I will look for the procedures that I wrote up (over a year ago) later this week. Along with posting a few pictures.

I have 35,000 miles currently on this dyno proven 600rwhp daily driver to back up all of my statements.

For those that WONDER WHY: My injectors failed at 160,000 miles and they replaced all of the fuel lines on top of the engine including the fuel rails due to corrosion. This time was under warrenty and it would have cost me over $3,800 if it hadn't been. So if I had put another 160,000 miles or so on the engine they would probably have failed again. But the engine didn’t make it that far, long story short it locked up 25,000 miles later. The block and pistons were scared really badly and I wanted to get the injectors out from under my valve covers for ease of access and safety. The LLY has dry injector cups witch means there is no coolant surrounding the injectors that can leak into the cylinders (this was the cause of my LB7s failure).

1. This LLY is setup like a LB7, NO EGR OR EGR COOLER!!! AND NO VVT

2. I’m using the stock LB7 ECM and a LLY FICM

3. The voltage and wire location between the two computers are identical from 2001 to at least 2005

4. The voltage to the Injectors may be different. This is why I’m using the FICM from a LLY (A Bosch engineer told me that all of the injectors that they supply to GM run off of a 12v supply line. He also told me that this engine would never run in my truck! 5 minutes after I got off of the phone with him the truck was running!!)

5. I spent more time studying the wire diagrams on the LB7 and LLY then the time it actually took me to install the engine.

Again I will post the detail later this week when I have time.

I made a mistake on my previous post; I'll try to edit it to prevent confution for future viewers.

I'm using the LB7 ECM and FICM.
I tried using the LLY FICM at first but I was unable to get the computers to comunicate using EFI Live. This is when I called Bosch and talked to an engineer to confirm that I would not burn up the injectors by using the LB7 FICM.

As for the different injector voltage numbers for the LB7, LLY, LBZ and LMM I've seen these numbers talked about in many different places, but only on message boards. Can we trace this information back to an original source, maybe a GM approved document?

I've found the procedure that I had written up last year, but its missing some part numbers, so please be patient while I look for this information.

The first one?
 

Hawk355

New member
Feb 26, 2008
14
0
0
The post where I said that I had made a mistake contains the correct information.

Yes, I used the stock LB7 ECM and FICM
 

Kat

Wicked Witch of the West
Aug 2, 2006
17,899
13
38
59
Norco, CA
I edited all the post to make the correction except for Mike's last one.
 

WolfLMM

Making Chips
Nov 21, 2006
4,005
25
48
38
AL
Dumbing down an LLY with an LB7 as someone wouldnt work due to VVT stuff IMO.

This is a cool deal!

Why wouldn't it work Matt? You would ditch the VVT at the same time. If you havent owned a LLY with fueling problems then you wouldnt understand the point of my post.:D
 

Hawk355

New member
Feb 26, 2008
14
0
0
This is for everyone who has asked about or has ever wanted to swap a LLY in place of a LB7, or has wanted to replace the heads to use the newer injectors.

First of all my goal was to have a LLY run with LB7 electronics. This means I’m using the ECM, FICM and TCM that originally came on my 2001 GMC.

I found the LLY at a local junk yard. It came out of a wrecked 2005 2500HD. They gave me the VIN of the truck that the LLY came out of and I took it to my service manager at my dealer to see what kind of work had been done to it.

I removed the EGR and EGR cooler.

I swapped the intake manifold and the passenger side exhaust up-pipe from the manifold to the new Aurora turbo. This does away with the useless holes that were used for emissions.

I made my own crank case ventilation lines out of rubber fuel line, tied the two sides together, using a T fitting, and ran one line down the front passenger side of the engine and out just below the oil pan. I installed an inline metal fuel filter in the vertical hose below the exhaust manifold to keep anything from finding its way back into the engine.

I swapped the crankshaft sensor, camshaft sensor, oil pressure sensor, the glow plug control box and all eight glow plugs from the LB7 into the LLY.

To reach the fuel pressure sensor on the passenger side LLY fuel rail I purchased a new fuel pressure sensor plug for a LLY witch comes with 15 inch tails. I cut the wires right at the original plug and attached the new one using the provided crimp and seal butt connectors.

Then I cut open both engine wiring harnesses and swapped in the LLY injector wires wire for wire into the LB7 harness at the FICM connectors (Diagrams Below). To do this I used Weather Pack Terminal tools, the tool has two metal rods that slide into holes on the front of the connector to compress the metal clips on the end of the wires and then gently pull them out of the back. Then they just snap back into the LB7 FICM connector. There is also a piece of plastic on the back of the FICM connector under the black cover that needs to be removed to allow the wires to be pulled out, I believe it slides out horizontally from one side of the connector.

After hooking everything up I wrapped up the wires to make a custom engine wiring harness, grouping wires together were I could but making sure not to pull on any of them.

When you are ready to start the engine for the first time, make sure you have EFI Live ready to make adjustments. I can’t assume every engine will need the same adjustments but I will tell you that with my stock tune the idle was extremely rough, it bellowed blue/white smoke and would not accelerate quickly. I was able to correct this by adding a considerable amount of timing. I was able to tune the engine to suit my needs and it’s currently making over 600 rwhp with no issues since the swap 35,000 miles ago.

Ok, please ask me any questions you may have about this swap, or let me know if you need more details.
 

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Dozerboy

Well-known member
Jun 23, 2009
4,826
401
83
TX of course
Cool hawk good luck with your truck. I guess this might prove weather or not its the FICM that causes the injector problems as some have speculated.