2013 Tacoma cranks won't start

Nice, yea when so much stuff has been swapped around diagnostics become tricky.

They will idle different after a battery disconnect, idle learn begins once coolant temp reaches 174F

 

Amazing! Way to go!

 

Just tested my theory, if there's enough residual fuel pressure in the line the truck will start and run with a 4 pin relay installed since the PCM commands low speed after the engines starts.
However if there's no residual fuel pressure it will not start with a 4 pin relay installed since there is no way for the high speed to work, also if you accelerate hard enough that the PCM commands the pump to high speed it will fall on it's face.

 

If figured it would fail if you have it enough gas. But wasn’t sure if it would start.

 

So, thanks to you guys I'm having a celebratory glass of brown water! The truck ran perfectly normal to and from work today. Started right up both times, no issues. I don't know what happened to start the problem, don't know how it ran on the 4 pin relay, but I owe ya'll .

 

I just read your explanation, yeah makes sense.

 

Glad to have helped.
Somewhere along the line that problem got built in, what the original problem may have been who knows.

That's why I like to do testing like that when I have time, seeing what known good is and creating a problem and seeing how things react can be a huge help in diagnosing things when there is an actual problem.