No start after steering column swap

[MONMIX]

Okay, this is not on an Explorer, but a GMC 1500 we have at my shop.
Hopefully the mods will go easy on me and let this stay here and see if any one has any bright ideas.
I think I will be fine because the mods here are the nicest and coolest in the world


Any way this GMC was in a front collision and apparenty the drivers knee took out the shifter on the collumn.
We started it up, had one guy daringly crawl underneath and manually click it into gear. Pulled it into the shop no problem. Put in a junkyard steering collumn. Totally identical. Every wire, every connector matched up perfectly.
We swaped the ignition so the customer can keep the same key.

Upon start up the vehicle starts right up runs for three seconds and then dies.

It fires up, so it IS getting fuel and spark. You CAN NOT keep it running by giving it gas. It has NO aftermarket security.
All wires and connections have been double checked.

Every time you start it, same thing. Three seconds of run time and then it dies.

My self and the other tech working on the job are stumped.

And educated guesses ?

 

[falls guy]

What year? There should be a switch down lower on the column no? Take the one off the old column and put it in. Thats the only thing I can think of. Hope this helps?? Good luck.

 

[section525]

Maybe theres a chip in the key and it doesn't match the receiver deal in the column? Or is this an older cheby?

 

[MONMIX]

Nah late 90's at least. Maybe into 2000

 

[MONMIX]

cant be the key-chip cause we switched the ignition, and we did try the old one too.
the only thing left on the origonal collumn is shift linkage and harness stuff.