mheath31806

I've been reading forums in here for a while and finally subscribed so I can learn more. I've searched for an answer to my question but can't find one pertaining to what I'm trying to do. I have a 2000 GMC Sierra 1500 with the LR4 4.8. I am looking at swapping it out for a 5.3 or a 6.0. My question involves the computer. I know if I keep the factory computer then I need a custom tune to make everything run properly. However if I find a stock engine with a computer do I still need a custom tune or can you literally take out the factory computer and replace it with the one that comes with the engine with no tuning required. Thanks in advance for any help or guidance.

ChopperDoc

Depends on if the transmission and gears also match. In many cases, they should. If everything matches you can drop a stock engine in with stock tune and be good to go. If there are differences like a cable throttle body vs a electronic one, then that’s an issue. Most of the 0411 cable computers may not have the card for DBW throttle bodies. The more details you can post the better with these things. I know a good bit about swaps, but the devil is in the details. For example a 4L60 computer will need some modifications to run a 4L80, and you have to swap some pins and do some mild tuning for the segment, etc.

To your question, if you get a donor engine, trans, harness and PCM, then no, you don’t really need a tune unless the gears are different. The only issues there would be BCM related depending on computer type. So in some cases you’ll have data issues, and things like TCS won’t work, or it will cause gauges not to report properly, etc. I’m trying to stay general, since there are about a million possibilities.

Also, this should be in the tuning section.

mheath31806

Thanks for the reply. I will try to get it into the other category. Sorry for that. Also the truck is stock. It has the 4L60 and I am planning on a new transmission but sticking with the same. I know gearing wise it would need to be tuned to run correct on a gear change. I was just curious on the computer specifically for the engine. So If i read what you said correctly. If I found a stock 5.3 with a computer I should be able to drop them in without a custom tune?

ChopperDoc

Yes, you would be able to drop a stock 5.3 in with no issues, provided the tune on that computer matches your trans. There are manual tunes out there, and so forth, so that's about the only consideration really. The engine should run fine on it's own computer. If you want a slightly cheaper way, verify the computer type, and if compatible, you can just flash your existing computer with a stock 5.3 tune. I got an LS3 to run on a 98 PCM with a stock flash in it, technically.... The numbers were just carried over since the calibrations don't match up. It's still pretty easy when dealing with OEM hardware in any case.

bbond105

What about VATs, wouldn't they have to be disabled?

ChopperDoc

Yes, probably. Good point, forgot about that.