After it sits for a while/overnight and before turning the key, push in the schrader valve and see if there is good pressure in the fuel rail. Obviously take care not to spray fuel everywhere. Mine ran fine once started, no misfires, but took a few seconds to build up the lost pressure from the leaking injectors. I second getting that cam code resolved.

 

You could even leave a gauge on the fuel pressure schrader valve when you shut it down and watch it over the next few minutes, hours and then overnight. At the very least, like suggested above, just confirm fuel pressure is there at all, that's at least a start. If there's even SOME pressure then the fuel is present at the injector and that mostly rules that issue out, if there's no pressure then take my suggestion to see how long before it's falling off and why.

 

HOPE EVERYONE READS THAT LAST PART, easy way to get messed up if you don't know better. I wouldn't have known this.

 

Thank you for all the suggestions, everyone! I'll make sure to report back when I have more results. Currently working with ACE and Speartech to figure out the speed sensor issue.
The cam code hasn't come back recently so going to put that one on the back-burner for now and confirm fuel pressure first.

For those interested, here's the cam that I went with: BTR GEN III & IV TRUCK CAM - STAGE 1 - V2 - BTR30612120

 

How much Transmission Fluid have you guys used when putting everything back together?
Getting ready to pull the torque converter & replace the bell housing, getting my fluids together...wondering if I need to fill the whole system up again or just a top up?

thanks

 

If you can find a local tuner that has HPTuners, EFI Live, etc. they might be able to take a look and help narrow down or sort out some of the idle / starting issues. I also found this LS Droid app, which is supposed to be a free option to read GM PCM tunes with an Android device and certain OBD readers. I haven’t tried it, but might be worth buying a junkyard PCM and seeing if it works. I would, but I don’t have any Android devices.

Ls Droid

https://ls1tech.com/forums/pcm-diagn...-released.html
I would just do a full drain and refill. Probably a good idea to drop the transmission pan and change the transmission filter while you're in there. You have to disconnect and reroute the trans cooler lines, which will make a big mess if it's not drained.

 

Thanks Cap!

 

Some updates!
Swapped out my cam sensor and the engine fires up within 1-2 seconds now which feels just like it should. Ironically the cam sensor that I pulled the engine with from the junkyard is the one that I put back into the engine. The new one I bought and installed while rebuilding the engine is the one that was causing my issues. For some reason I'm getting flashing M&S lights more frequently as of late. Need to read more about what could possible cause this, I have a feeling it might be my old battery that came with the car.

As far as the vehicle speed sensor reading on the GM side, I'm still troubleshooting. Got familiar with a multi-meter this weekend and confirmed all my grounds are showing proper resistance measurements. Cleaned up as many of them as possible and reconnected. Next on the list is to try a different grounding point for the GM ECU. I did lengthen the ground wire on the GM harness to have it reach the drivers side ground strap and that could apparently cause some issues with my wiring and the ECB box. Going to move the ground to one of the holes on the valve cover that gave me a good reading when testing.

My idle seems to have improved as well. I'm not sure if it's due to me cleaning up some of my grounding points but I'll take it!

 

For those that have a whistle from the flex plate, this is what I am using to plug some of the holes. I'd suggest a minimum of 6. I found these at Lowes but you can also order from Lowe's online.

 

Good option to fix that whiling sound. My wife heard it the moment she drove it. ....... naturally.