Hi, and welcome to Just Answer!
I hate to be a pain, but to answer your question, I'm going to have to ask you a few first, let's see if we can come up with a solution to your problem. Some of the questions may seem strange, but answer them as best you can.
When the key is turned on, does the check engine light come on for a few seconds?
When the key is turned on, do you hear the fuel pump run for a few seconds?
Have you had the computer checked for fault codes?
Finally, have any repairs been done recently besides the PCM (trans removed, anything at all?).
Looking forward to hearing from you, sorry about all the questions!
Just to clarify a bit..
When you turn the key from off to run, the check engine light does not come on for a few seconds (with all the other indicator lights for bulb check)? Nor does the fuel pump come on for 2-3 seconds?
Not while your cranking on the engine, but just when the key is turned on.
This is a very important detail, and I just want to make sure we are understanding each other.
Just making sure we were on the same page... The computer is unresponsive.
This is caused 99% of the time by a shorted sensor. The three big culprits are;
If any of these 3 sensors get's shorted out, it will put the controller to 'sleep' for a lack of a better term. Unplug them one at a time, then cycle the key and watch for the check engine light to come on for bulb check and the fuel pump to run for a few seconds.
When you see the check engine come on for bulb check / hear the fuel pump run you will know you've found the shorted sensor, replace it.
It's possible you have a power or ground issue to the PCM, but 99% of the time it's one of the three sensors above shorted out. Depending on how the truck was built it may or may not have the vehicle speed sensor, I believe yours will though.
The reason I asked about a recent transmission replacement is that often times the crank sensor wire gets pinched between the bellhousing and block, then 200 miles later when it finally wears through the insualtion the truck quits + acts just as you describe.
Check it out, let me know what you find. It's most commonly the crank sensor. If this information helps you out please click accept, if it doesn't reply back and we'll move on to the next step.
With the sensors unplugged could your scan tool communicate with the PCM? It will generally be immediately obvious as to what sensor is at fault as you'll hear the pump kick on along with all the relays when the key is cycled on.
It looks like we are moving into the 1% side of the operation.. Give me a few minutes to put together some info on you, the next step is checking powers + grounds to the PCM.
If you've got a second while I'm compiling it and the scanner / code reader hand, see if it can access the pcm with them unplugged.
I'll reply back in a few minutes,
Does your PCM have one connector, or three?
I thought it would. My service info keeps showing a newer style (3 connector) PCM, and that's not going to help you a bit. I'm going to keep searching for the correct pinout, and if I can find it I'll post it.
In the meantime I'm going to opt out in case another expert has the info you need and they are just waiting for me to get out of the way.
Please don't click the accept button as I haven't been much help to you and I'm sorry about that.. At this point they haven't charged you for the question and you can get your deposit back if nobody can come up with the info you need.
As a parting though I've seen the ground wire come loose / break that's hidden behind the power steering pump on the drivers cylinder head.. The large ground goes to the battery and the small ground goes to the PCM, if it's bad you will have a no response. That's a bit of poke and hope though without checking at the PCM.
Hello Buzz and welcome, Super mechanic here. I was wondering if you had ever checked the fuse links and fuses. You want to have power to the ignition coil as well as the injectors when the key is on.
They are powered through the ASD relay, you can test it with a 12v test light, here is what it looks like,
You may want to switch it with another good relay with the same numbers on it, just to see.
Here is a wiring diagram that may help in pinpointing the power loss, thanks