Rough idle, Timing randomly adjusts

[tayto]

Well timing was okay but I don’t know how to explain it haha. The mark was so far retar*ed when the 5.0 stuff was hooked up. But anyways, ran, but then I unplugged the map sensor and it shut the truck off as it should. Put all the original sensors back on…. And now she cranks but no start hahaha. This engine is a nightmare. My money is on the ECU. I was able to get power to my obd port… just kept flashing 12. I know that means no issues, but it wouldn’t change. Stayed flashing 12 and the service light is on still as well.

flashing 12 is normal, that code is always there. what sort of shape is the harmonic balancer in? possible your TDC mark has moved. you set timing to 0* with the ESC wire unplugged right?

 

[ChevPasmore]

flashing 12 is normal, that code is always there. what sort of shape is the harmonic balancer in? possible your TDC mark has moved. you set timing to 0* with the ESC wire unplugged right?

Harmonic balancer is good. Yes timing was set to 0 with wire unplugged at operating temp. But after putting the other parts on it, it through everything out of whack. So haven’t been able to reset it again after going back to the other stuff as it is now not running

 

[tayto]

Harmonic balancer is good. Yes timing was set to 0 with wire unplugged at operating temp. But after putting the other parts on it, it through everything out of whack. So haven’t been able to reset it again after going back to the other stuff as it is now not running

it's best to replace one thing at a time. i know it's tempting but resist the urge. Let's identify the injectors, ECU, what calibration is in the ECU first. Were you able to get any of that?

 

[ChevPasmore]

it's best to replace one thing at a time. i know it's tempting but resist the urge. Let's identify the injectors, ECU, what calibration is in the ECU first. Were you able to get any of that?

it's best to replace one thing at a time. i know it's tempting but resist the urge. Let's identify the injectors, ECU, what calibration is in the ECU first. Were you able to get any of that?

Unfortunately numbers were worn off on the injectors, but I’m positive they were the 350 injectors after every other part on the top was from the 350. ECU I’ll be doing this weekend as I unfortunately ran out of time today due to family stuff while trying to figure out everything else. But I’m pretty sure the ecu is still the stock 1990 with the 305 parameters. I’ll verify 100% this weekend if not sooner if I can get the time after work.

 

[ChevPasmore]

I appreciate everyone's help.
I am an idiot, when I swapped out the throttle position sensor, I put it on wrong, I put the tab behind the bar on the throttle body and not in front of it. Timing is okay, now it just surges on start up until it somewhat levels out.
Next up is IACv and I believe that will sort everything out. Just been busy to verify the ECU part but everything is good when shes running. Will report back later tomorrow after the IAC is swapped out.