fatratchevy

Searched and searched, but still couldn’t find my answer. . . . Sorry.

My cousin killed his 4.8 liter (LR4) in his 1999 Silverado, so now he's looking to replace it. Me being a car guy, I told him he should take the opportunity to upgrade and should swap in a 5.3 or 6.0. I figured this would be an easy swap, but before he goes and spends $1200+ on a motor, I'd like to make sure all our bases are covered. It seems simple, but I’m getting confused the more I read here.

I've been looking at complete drop out motors on eBay and 5.3's seem to be common. The questions I have are simple:

1. If I get the ECM and wiring harness from the donor car, is it simply a plug and play into his truck regardless of the year the 5.3/6.0 came out of?

2. Starting in 2002 (iirc) the Vortec's came with drive by wire, my cousins current truck is drive by cable. . . . . is it just as simple as keeping his original wiring harness and Throttle body, but swapping the ECM from the donor car? Any pinout differences between the 5.3 and the 4.8, or from year to year. Isn’t the ECM going to be looking for the throttle signal from the peddle if we used the donor ECM (2002+)?

3. What about O2 sensors from year to year, I read a thread where someone said you should keep the O2 sensor from the donor harness (assuming that is used instead of the original harness). Is this due to a connector difference, or a pinout difference?

4. If he kept his harness and ECM, just swapped in a motor (an LQ4 we'll say), can he just get his ECM reprogrammed to LQ4 software? Are there any differences in the harness/sensor location on an LQ4/LM7 that will keep the original harness from plugging right in?

Basically, we're looking for an inexpensive, yet easy way to swap out these motors and gain a little performance in the process. He's in college right now so he doesn’t have too much dough, but I told him we should be able to do this in a weekend, and my labor would be free. . . .

Anyone have any advice. . . . am I thinking about this too much and could it really be as easy as pulling his 1999 LR4 and swapping in a 2000/1/2/3/4/5 LM7 or LQ4?

Thanks guys.

LS1MCSS

iTrader: (18)

It would probably be easier to use his current pcm, harness, sensors, and just re-tune for the bigger motor. This assuming both motors have the same type reluctor wheel in them.

pj4553

iTrader: (6)

Is he looking to make his truck perform? I'd say skip the 5.3 and go straight to a LQ4 or an LQ9. The swap is very easy and very common. Do a search over a performancetrucks.net (look up at the top of this page) your user name and password both work on that site as well. I believe there is actually a write up on there how to do a LQ9 swap step by step.

hope this helps

fatratchevy

Thanks for the responce. Is there a place I can find what reluctor wheel for each modle/year?

He's not really looking for huge performance gains, he's still in college so money (i.e. gas cost) is tight. Really he's just looking to jump up a little, mostly on my recommendation. I'll check out performancetrucks.net, thanks for the tip.