I have swapped a 2005 4.3 into my 2001. I replaced the transmission and transfer case as well. Upon trying to start, I get a brief start but won't continue to run. I have good fuel pressure. I swapped all of the engine/trans wiring as well as the ECM. Does anyone have any advice as to where to look.
Thanks.

 

Do a security relearn search. Jamaroon had to do this a couple of times on his Sonoma.

 

I moved this so second gen tech since this is not really a build thread.

 

I did the relearn and the security light went out. It still won't run. The fuel gauge only works in the start position, seems to cut out in the run position. I switched the BCM to the one from the 2005 but it didn't make any difference. Any ideas what I should try next?