2004 silverado 4.3 to 5.3 swap, starts and dies

[lxfox]

I just completed my 4.3l to 5.3l swap and cant get the truck to start. it will crank and start for a second and then die. I disabled vats in the system tab, set the dtcs for vats to no error reported. I have also did "write entire" when i flashed it with no luck. i am using the original pcm from the v6 to run the v8 but im pretty sure i swapped everything over. the truck was originally a v6 5spd and now is a v8 5spd. everything is stock on motor, all stock sensors, no cam, just a cold air and shorty headers. motor and harness was out of a 2005 silverado any help or suggestions would be appreciated. attached is the tune file.

2004 tonys 1500 v8 tune vats dtc.hpt

2004 tonys 1500 stock file v6.hpt

[5FDP]

Did you write a 5.3 tune file to the computer??

The vehicle info page still says the file/VIN is for a 4.3. Starting with a V8 file is what you want.

[lxfox]

Did you write a 5.3 tune file to the computer??

The vehicle info page still says the file/VIN is for a 4.3. Starting with a V8 file is what you want.

i copied everything over from a v8 tune file. couldnt find a v8 file with the same os so couldnt segment swap it.

[5FDP]

Pretty sure you still need a full flash with a V8 file, even if you found the segment swap that wouldn't be enough because the base file on the computer is still made for the V6.

If you kept all the wiring for that other engine and used the drive by wire throttle body and pedal assembly it won't work on a V6 base file. If you kept the cable throttle body and added an IAC/TPS you could go into the computer and turn that stuff on afterwards.

[lxfox]

Well I finally found a v8 file with the same os as the v6. found a 2004 2500hd 6.0 uses the same os. I segmented the engine, engine diag, and system onto the v6 pcm then changed the airflow tables and such to match a 5.3l and motor fired right up and runs great drove it around that block a couple times. also I am using a DBW throttle body and harness. only problem I have now is that the tach is way off, like doubling the rpm but on the scanner its correct. but at least it runs and drive lol