basically just need to copy LLY main and pilot pulse width tables into the LB7 tune. LLY injectors are a fair bit smaller than LB7 injectors, so more pulse width is required to allow it to run smoothly at lower RPM's.
I have seen the impossible!
- Thread starter Sandracer799
- Start date
I understand the LLy injectors are smaller than LB7 but how do the other injectors stack up in comparison?
hey hawk, saw your how to. just a quick question. im guessing i have to have efi live to tune the motor in after the swap? im kinda newer to the dmax life. i have a '03 gmc with a lb7, but i just picked up a lly out of a 04.5 chevy for $600 and only had about 90k miles. i know i might as well of stole it. lol but i want to do the swap, but dont want to run into problems. i see i got to switch the sensors you have listed and switch the injector plugs one by one like you have shown in the diagram. but is it just that easy? thanks alot and cant wait to hear from you. --joe
Last edited:
Good Questions...
My reason for swapping out the cam and crank sensors was that since I was moving the needed wires from the LLY harness to the LB7 harness it was two less wires to move. The sensors use different style connectors and are easier to swap than the wires.
As for just plugging the LB7 FICM into the LLY harness, I didn’t touch the wire harness on the truck, only the engine side and I believe the cam lock connectors for the LB7 and LLY are different. I don’t have both connectors in front of me at the moment and I can’t find the schematics to confirm it. So I had to move the necessary LLY wires over to the LB7 harness. Unfortunately this swap was a little more involved than just “Plug and Play”. But I do feel that this way was easier then messing with the wires under the dash.
I won’t argue that there aren’t easier ways to go about this swap. It’s just that in my mind this was the easiest way for me to make sense out of my goal, “to run a LLY on all LB7 electronics”.
The only necessary changes I made were to the Injection Timing (C) and Injection Timing After Pilot (C,D) tables.
I raised the lowest numbers on the chart up to 12.5 degrees and smoothed up the surrounding cells to tie it all together. I would start out by trying to keep the timing as low to stock as possible. All you want to do is raise the timing enough to smooth out the idle.
For performance reasons the tables were already modified with the higher RPM’s and mm3 Per Stroke cells around 25 degrees. I’m reluctant to post a screen shot of the tables because they are based off of someone else’s work.
I tried this approach with a stock LLY tune but had poor results. I would love to hear what method a “Pro EFILive Tuner” would take to address the issue of the rough idle that I experienced.
If you have access to the proper tools, then yes, it is relatively easy. Just make sure you only remove one wire at a time from the FICM connectors so you can keep track of which wire goes where.
WOW! i will be really lookin into this in the future when my injectors go out next. My only draw back from it is how the LLY injectors will handle the supposed "96v" the LB7 FCIM puts out but i guess there is only one way to find out!
Hawk, i think its awesome you were able to do this swap as easily as you said and that you show it can be done (not sayin it was impossible).
Should the time arrise and i do this ill hopefully be jsut be puttin heads and such on and no more but hell i may jsut do a whole motor build lol
Hawk, i think its awesome you were able to do this swap as easily as you said and that you show it can be done (not sayin it was impossible).
Should the time arrise and i do this ill hopefully be jsut be puttin heads and such on and no more but hell i may jsut do a whole motor build lol
These rates were taken in Drive
1= -2.19
2= 2.75
3= -1.38
4= -1.52
5= 0.95
6= 2.73
7= 0.11
8= -0.89
Last edited:
Bringing this back up to ask a question or two.
If you swap to LLY or LBZ heads and use LLY injectors/harnesses, do you need to run the LLY fuel lines/rails too?
What is different on the LLY top side that would preclude a person from running the LB7 intake manifolds/turbo?
If the LLY injectors were opened up to flow the same as the LB7s, would the idle tuning issues be allevated?
If you swap to LLY or LBZ heads and use LLY injectors/harnesses, do you need to run the LLY fuel lines/rails too?
What is different on the LLY top side that would preclude a person from running the LB7 intake manifolds/turbo?
If the LLY injectors were opened up to flow the same as the LB7s, would the idle tuning issues be allevated?
Tom,
you need to run the lly fuel rails and lines but you use your lb7 turbo and intake manifolds and turbo...
the tuning issues with opening the injectors(or non opened)I have no clue about... but that is a good idea about maybe matching the injectors as close as possible to lb7 ones...
Since you have a truck with the newer wiring harness have you considered just making it an lly completely and then just tuning for an lly?
I've been wrestling with putting lly heads on for some time now...
if you still have my number from my trip up to michigan, give me a call sometime...we are in the same shoes brainstorming where to go next with a budget build...
Last edited: