Well, a lot of water under the bridge since I last wrote. I finished up the bed mat and got everything back in place. Looks a lot nicer than seeing the butt ugly access panel. Plus it's much more anti-skid than the spray in liner.
I also repaired the starter circuit wiring and ran a dummy wire for use with an ECU controlled fan relay in the event the PWM fan controller takes a dump. Having the wire there will probably mean I'll never need it, but just in case.
I wired a new MIL in parallel with the one in the dash and it didn't work initially. Finally figured out I'd piggybacked it onto the wrong wire where it came out of the loom. When I test fired the engine, it went out completely as did the MIL on the dash. I tried several configurations, but the dash MIL looks to be working correctly now. Not sure what happened, but I left the new MIL wired in parallel with the old anyway.
Pulled some much needed maintenance (oil change, fluid checks, etc.) Also removed all the plugs to have a look. They looked pretty crappy, but I figure they're like that due to all the past fuel issues. They should clean up after some highway miles. While all this was going on, I removed the ignition switch and put the fuses back in the Advanced Keys pushbutton start only to find the truck would crank but not start. I put the stock ignition switch back in and it started just fine. Put the fuses to the AKPBS back in and it started with no problems. So I just left the stock switch plugged in and cable tied it up under the dash for the time being.
It was finally time for a test drive. Ryan and Rachel (twins from Houston) are visiting, so Ryan and I hit the road. Drove less than a block before deciding something wasn't right. Popping and banging like it did the time I had a vacuum leak. Pulled over and checked but that wasn't the problem so we limped back home.
When I originally installed the vacuum referenced regulator, it was set at 60psi out of the box. But when you attach the vacuum hose, it pulls about 5 or 6psi off at idle. According to the documentation that came with the LS3, it needs a vacuum referenced regulator set at 60 psi. So I adjusted the pressure up to that amount at idle and it seems to be running better although not 100%. It still has an intermittent low speed surge and is harder to start than it should be. It will start on the first try as long as you don't even rest your foot on the accelerator pedal. I have a bad habit of driving with two feet and if I come up to a stoplight with my left foot on the brake and the right still resting on the gas pedal, it will want to stall out. So I'm going to have to retrain myself to either use my right foot for everything or move it well away from the gas if I need to stop.
I've read that poor idle quality, hard starting, stumbling and etc. are fixable via the tune. However, I'm reluctant to take it back to the guy that did the work on it back before we went on our trip. His communication skills left a lot to be desired. I don't know whether I could take the truck in to my local Chevy dealer who sells the GMPP crate engines and have them return it to the original tune to see if that improves it or not. It's drive-able but it doesn't instill confidence when it displays these little quirks.
I have an Innova 3160g code reader / scan tool due to arrive tomorrow. Jason7121 recommended that I connect a scanner and drive around to capture some live data. It should also allow me to see if the ECU toggles between open and closed loop like it's supposed to. I don't know if the permanent emission codes that were set are interfering with the operation or not. Will post more when I know more.