Well..... That was quite the journey....
This all started with the LB7 #7 injector sticking open. That in turn took out the valves & piston in cylinder #7. Since this was the tow vehicle for our racing team we didn't have the luxury of stopping... as a matter of a fact I drove that baby for another 3000kms all over the province of Alberta before it finally said ENOUGH! Even though I changed that injector after the first trip, it was too late, the damage had been done. I changed the the oil after every drive because it was full of fuel. On the last part of the last race trip coming up our back alley the LB7 bottom end gave up. A rod bearing spun as I was pulling up my back ally coming home from the LAST race... I LOVE that truck!!!.
By that point I had already studied the conversion from LB7 to LLY extensively & there was a couple very informative threads & videos out there at that point showing how others had done it so I was off. I was lucky and found an 04.5 LLY with a blown head gasket in storage locally that came with wiring & ECM & FICM, nearly everything I needed to do the 03 to 05 Duramax swap. I had all the info from many others and the pieces I needed. I got the engine gasket set, a head stud set, new up & down pipes and too many other little trinkets to list. I decided I wanted to stick with the mechanical wastegate turbo but I had already sold the IHI turbo from my original LB7... so Kijiji here I come, I tracked down an other IHI turbo that ended up being cracked beyond repair but that put me onto a local shop that deals only in Duramax repairs he sold me another IHI that was in good shape. I had a new cartridge installed and had it bored out to 64mm and ordered in a Banks Big Head and put that on along with a PPE boost increase valve just for good measure.
Here's where SH*T went south. After talking to the tech at the Duramax shop, he convinced me to go with all LB7 electronics since I was going with the LB7 turbo system. He told me he had tuned a previous customers truck who had done a similar swap. So after a long conversation and since I was having him do the tune with his EFI live... I chose that path even though all the research I had done suggested that being that I had a 2003 the best way was to go with the LLY electronics. So on I went. There was a couple videos & threads on line at the time that showed people that had done it in LB7 and said they were successful, so away I went. I hacked up my LLY engine harness and modified my LB7 harness to go with the injector connectors for the LLY, I did an AMAZING job, it looks factory. I swapped the crank & cam sensors as mentioned in the threads. I modified the LLY fuel lines to work on the LB7 FICM. I installed the glow plug system that comes with the LB7 harness. It was a work of art, y'all would have been SO impressed! I also took all the injectors to be tested & replaced four of them since they were questionable & the others had recently been replaced before the LLY had been removed. A buddy had come into some bad luck & his LLY FICM had failed so I sold him mine for a song since I didn't need it.
Since I had already removed my LB7 engine from the truck to use needed parts I was sure to replace the torque convertor housing bolts on the Alison 1000 tranny to the updated bolts & washers, input seal, etc. and retorqued as described in the bulletins, replaced the torque convertor with a billet unit to be sure there was no future issues that way. New engine mounts, radiator, starter, intercooler hot pipe, Banks intake with scoop, all new transmission cooler and power steering lines. I spent a FORTUNE on this thing. Next, I installed the redone engine. That went pretty much as expected. LOTS of work, LOTS of time, but after a number of hours(days) It was finally in & ready to turn the key....
The 1st night... nothing, it would NOT start, I quit for the night and did NOT sleep. The next morning I went out, turned the key and it sputtered, next try it burped & then it STARTED... ran like SH*t, but it started. For the next two days I smoked out my neighborhood trying to get it smoothed out. It was DUMPING fuel into the cylinders, It would NOT rev above 1500 RPM willingly. I finally disconnected the ECT sensor and threw it into limp mode & it actually smoothed out & idled well, but still wouldn't run over 2200rpm. After studying the numbers & much deep thinking I connected the Barometric sensor to a vacuum pump telling the computer that atmospheric pressure was 10hg lower than it actually was so it would lean out the fuel. That worked, I was able to run it.... at operating temp. The turbo would work, it would run... not great but at least I could drive it.
The 1st thing I did was drive it straight out to the Duramax shop to get it tuned in hopes that would smarten everything up. The owner called me up the next day saying he couldn't get it to start even though I had given him all the info on what to do to get it going. That was when he told me he was farming out the actual tune to "Mark" in Indianapolis and he would send all the truck info to him and he would load that tune later that day.... well... He did as he said... but, it fixed NOTHING, and "Mark" told him that the only way this would work properly is if I used a LLY FICM.
which meant.... rewiring EVERTHING! Re-acquiring an LLY FICM(Next to impossible) getting another LLY engine harness since I hacked up mine to go the LB7 route. So he charged me $600 for his extra F'ing around and loading Marks tune into the LB7 ECM and watched me drive away in a cloud of smoke.
I spent the entire next day going through all my auto wrecker connections trying to find an 05 Duramax that still had all the wiring for the engine & ECM harness and a FICM since I had sold my original many months previous. I ended up finding a couple but they were hesitant to sell what I needed & they priced it accordingly. The "last chance" was in a nearby satellite city. The staff were confused by my needs & really didn't understand what I was after so I ended up driving out & showing them EVERYTHING I needed MANY times to be sure they knew exactly what I needed. I asked/offered several times to extract the harnesses myself so I knew It would be done right but they assured me they could do it for me. So, two days later I get a text picture of the engine harness saying "Harness is ready" but, the ECM harness wasn't in the picture so I mentioned that. The next message was a picture of a harness CHOPPED on the transmission tail saying "This one?"
Well I snapped, I lost it!!! Once I was done venting, I just asked them the include the transmission end of the harness & I would splice it back together. They did.... & I did. But, while I was splicing it back together I couldn't help but notice that the cuts on the wire ends didn't match but I carried on and finished it up. After 3 hours of soldering I pulled the truck in & removed the ECM harness from the truck and compared them only to find that the one I had been working on all morning was 18" too short. They had cut the harness TWICE and left a foot & a half of it in the truck!
SO.... after venting my frustration to an empty shop for a few minutes I collected my thoughts & decided to splice the tranny tail piece from my LB7 harness onto the LLY ECM harness. This actually solved the Park-neutral switch change up issue between the 03 & the 05 but I found there is one extra wire in the connection to the transmission valve body that I also had to transfer over to the LB7 tail piece. So after another 4 hours of wire swapping & splicing I finally had EVERYTHING I needed. I installed the ECM & engine harness, the FICM and the original ECM I got with the LLY engine.
After completing the "emergency security relearn" I turned the key.... and she lit up like nothing had ever happened, it was FINNALLY running and running well. Today I took it back out to the Duramax shop to have him install the tune to get rid of the variable vane turbo & EGR codes, fix the fuel gauge polarity and add some bottom end torque. He did it & gave me a "deal". I have been playing with it ever since & it is AMAAAAAZING!!!!!!
Moral to this excruciatingly long story....
Do your homework & ALWAYS trust yourself more than you trust others if you've done your homework.
If I had followed that advice this story would have been MUCH shorter!!!!
oh ya.... AND LB7 ECMs and FICMs do NOT like LLY injectors!!!!
Thank you everyone for your help!
Farr OUT!!
