New guy needing help.

[Sean.d.murphy86]

Goodmorning group,
I'm about to undertake my first attempt at tuning my own vehicle and need some help on where to start. I have watched all the seemingly legit videos on YouTube from Goat Rope and HP.
With that said I'm not sure where to begin with my current project. My vehicle is a 2000 Jeep TJ that I LS swapped 7 years ago. Original LS engine was an LM7 from a 2003 silverado backed with a 4L65E. Recently, I for some unknown reason decided to change the engine to a L33 (LS6 clone) I had rebuilt for another project that I went a different direction with.

Vehicle: 2000 Jeep TJ
Engine: L33 bored to 5.7.
LS6 factory pistons.
243 heads
Stock Gen 3 truck intake.
Stock Gen 3 factory truck injectors.
BTR stage 2 truck cam.
Camshaft position sensor harness
extension.
Single pole cam gear (half moon)
PCM from 2003 silverado.
Knock sensors from gen 4 engine
relocated to the side with
extension harness. (Harness was
intended for gen 3 engine)
Cam sensor relocated to timing cover.
58T crank trigger wheel changed to 24T
All sensors other then knock and
camshaft position are factory gen 3.
Harness: PSI (brand new)
Transmission: 4L65E

So essentially I stuck a Gen 4 engine in a vehicle set-up for a Gen 3. When I initially installed the first engine I had a local guy tune the PCM and build the harness for me. I was not satisfied with either and had to make extensive modifications to the harness to fix what was done. In the end I never felt it was tuned correctly but ran it for almost 7 years with no real issues that impacted driveabilty. I had finally had enough of the thought of my half-assed harness and decided to replace it with brand new one from PSI. That then spun out of control and down the proverbial rabbit hole I went which is how the engine ended up getting swapped out for this LS6 clone.

After performing the swap I have a few issues to deal with.

Issue one.
Engine would not start without extensive cranking and then did not stay running. Computer had a code for camshaft postion sensor circuit voltage high. After researching converting from a rear mounted cam sensor to front mounted cam sensor I found I may need to switch wires one and three in the pigtail. I did that and the jeep starts and runs however now I have a code for Cam position circuit voltage low. I will post the exact code later as I don't have my notes in front of me and cannot remember the code number. I believe the current code is P0342 but will confirm and update my post. Engine will also backfire occasionally when starting but once running idles fine and revs up like it should. I have not found any issue with the wiring or sensor. Sensor is for a LS2 in a 05 GTO which is what BTR told me use.

Question for the group. Is it possible this issue could be resolved by tuning?



Issue 2.
P0107. I have not diagnosed this issue yet so it's possible it's dirty or needs to be replaced and may be nothing more then that. This is number one in the repair cue before attempting to tune anything.

Once I diagnose the MAP sensor situation I am somewhat confused as to where to start tuning. Knowing that my current ECM is "custom" tuned and set up for a gen 3 5.3 with the current engine being essentially a Gen 4 5.7 where do I begin?

Do I start with the tune already on the PCM or do I copy a factory tune and begin from scratch?

Do I need to copy a tune for an engine dimensionally similar to my current set-up?

Do I need to start with a tune that uses the same instrumentation that my current set-up (knock sensor location/type) has?

Please assume I know absolutely nothing about tuning a vehicle. Thanks in advance.