I haven't touched a factory ECM since I went aftermarket in 1992. I don't know if your harness would plug in, you would have to call, the sensors would work. I only use the Fast stuff, there are other brands out there. And as Dustin said, it's not for the beginner, but there are shops out there that can set up the ECU so the boat starts and runs. Then like I said before, you can link up your laptop to their computer and they can tune your boat from anywhere there is an internet signal. You drive the boat, they tune in real time, you can actually see and feel the changes as they're made. They can run data logs, run closed loop to keep from melting the motor down during the process. It's not for everyone, it's just an option.

While it may not be for everyone, you can successfully self tune with a little research. NA applications are obviously easier.

I have the Holley Comander 950 with wideband O2, tune mine on the fly. You can run datalogs and make changes later.

All that is fine and good, yes I tune my own mefi4 system now on the water too and most guys capable of building their own motors probably could too if they just educated themselves a little BUT:
THIS GUY HAS A MERC 555 ecu, he has a harness with it that has more crap plugged into it than the older ones ever dreamed of, there are no plug and play ecu's that fit his harness to convert to that I have heard of . He could convert it but it would be a significant expense and a step backward. He needs to get on the phone to his tuner (or one of the other 2 of 3 that can do it) and give them detailed afr's and map settings/fuel press etc and they can start tuning AFTER he finishes changing things/finishes making modifications (there was mention of going to a different intake later), Smitty

Just curious, what ecu does GM use on the 2011 Camaro 6.2

Thank you everyone for all the input. I am going to make a few phone calls tomorrow and I will keep everyone posted of the progress if they are interested. I did find someone with a Merc Scan tool but I haven't had chance to it use it yet.

Good luck, hope you get it straightened out.

I remember reading a thread and there was a A/F meter that did data logging. So, couldn't a person use that datalogging to help get a mail-order tune much closer?

It would have to be better, it may only log RPM and A/F ratios, load changes and acceleration would still be a guess. It's hard to imagine 3 people have cornered such a market.

Correct, he should have the original programer get it right. I was just stating what I had, not that he should convert his over.

I was just trying to get thread back on track, Smitty

Winter is over and we are finally getting our engine project wrapped up hopefully! We have been in New Orleans for a week with our boat and hopefully today we will be taking her out on Lake Pontchartain for a short test ride.

After talking to a few people in the industry it was made clear to me who should be doing the work on our engine. My limited engine and ECM knowledge was also telling me there IS NO WAY ANYONE CAN PROPERLY TUNE THE 555 ECM WITHOUT IT BEING ON THE ENGINE! This shop is able to turn the ECM while it is on the dyno or in the water.

The Mark of Precision Marine has been fantastic, he calls every evening to ask how our day was, what we did in the city and more importantly to give updates of the progress and troubles. I know we are finally in good hands! It took them 3 hours just to get the idle under control, the engine was under a 40% load at idle and they were amazed how I was able to keep it running while shifting. I told them it wasn't easy! They had the boat on the water twice to make sure everything is doing what it should. I am confident in these guys! I just wish I had learned about them sooner. And from this day moving forward I will be using them for all may engine's needs. Besides, I cannot think of a better city to hangout in while they work on our boat.

Knowing what I know now, I would have done things completely different!

I would send the bill to Tyler Crockett and tell him if he didn't know how to program the ecm he shouldn't have taken on the build .