Engine won't fire

Hello,

This sounds like the crankshaft position sensor (hall effect) when out they do out all the time in these trucks but to be sure run down this guide and check out the diagrams below.

https://www.2carpros.com/articles/car-cranks-but-wont-start

Check out the diagrams (Below). Please let us know what you find. We are interested to see what it is.

All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.

Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.

2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.

3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.

4) If all of these things check good, then you would need to do a complete compression test.

Once you have determined which of these functions has dropped out,
you will know which system is having the problem.

The rest of the tests.

How do you know it's not the alternator if the engine doesn't run? What are the symptoms?

Jumping it the wrong way could blow a fusible link/s

Yes, you do need to complete the rest of the testing for me to give you any kind of conclusion as to what might be the problem. Many functions share common components.

No, it doesn't

Fusible links are off the positive cable of the battery by the fuse box.

The asd relay has 2 powers, one key on and one battery. The 3rd terminal is the load and the other is the pcm grounding the relay. Verify the powers first.

Roy

IT sounds like the lever isn't moving the ignition switch far enough. Have you checked it?