in need of advice thanks in advance..4.8 to 5.3

[miltonbradley]

just put a 2007 5.3 in my o5 Tahoe which had a wore out 4.8.. ecm from 5.3 didn't plug in right so Iam trying to use the 4.8 and flash a stock 5.3 tune butt... when I scanned it it came back 4.3 ecm and doesn't try to turn over or anything dash lights and everything comes on but nothing from motor also this is my first time trying to tune anything.. would the car atleast turn over before I flashed ecm...advice.. suggestions.. anything would be highly appreciated I also have a log from scan I could post if need be thanks..

[5FDP]

Slow down when reading stuff. All the P59 computer will say exactly what the computer can be used for. If you read it closer you will notice it says P59, GM GEN 3 V8 , 4.3. Notice the "comma" it means it can be used to run both engines, it all just depends on the calibration installed.

If you are using the same computer from your 4.8 Tahoe, it's still a 4.8 tune and not a 4.3 V6. It wouldn't have run if it was a V6 computer before hand.


I don't know what you did still. If you tried to write somebody elses 5.3 tune into your computer this could have caused you a problem. Never ever license or write someone else's file into your computer. That only costs you money and possible problems.

What should be done here is that you take your 4.8 tune and then find a 5.3 tune from the same year truck to make it easier. Then copy over the 5.3 tune information that you need and save it as a new tune. Then you can write your file with the new changes back into your computer.

[miltonbradley]

thanks for ur help I been doin non stop research and the ecm comes back as 4.8 which is what was in there.. motor came back as 02-05 5.3 lm7 so either my ecm might be messed up or something isn't plugged in .I haven't even got to the tune but I was gonna just go off what I red about comparing files and dragging the tables kinda leaning in the direction now of just ordering a pre flashed one then taking my time on learning this program..didn't know I was gonna have to just jump in..but yea that's good to know about the comma I started to think I was bamboozled by the ppl who sold me the Tahoe..soon as I get it to run ill post the scan or tune cause im sure ill need some help hopefully not but I do have headers and intake hoping to get a cam to but id like it to be running first

[badco]

I recently did a 4.8-5.3 swap in a 2002 with a 5spd. Simple deal as far as stock to stock. Used the 4.8 pcm and pretty much coppied a 5.3 on fuel, timing, and ve. Also looked where a manual and auto were different between 4.8s and made the same % change on the 5.3. Im very new to this but so far only one thats been a lil tough is the p10 4.2