carfreak06

I'm planning on swapping my brand new ls3 into my 05 ls6 cts-v, but unlike Mallet Hammer's swap, I have the harness, ecm, and sensor package for the ls3. My question is whether the ls3 ecm will work with the vehicle. Is the programming for the vehicle (stability control, gauges, cruise control, mpg metering, warning lights, etc.) on a separate computer, or would I have to get someone to copy the programming from the ls6 ecm to the ls3 ecm? Also, after I get the swap done, hopefully in the next month or so, I'll have an 50,000 mile ls6 with clutch, ecm, harness, sensors, and a brand new pedal for sale. What would be a fair amount to sell the package for?

rocket2ya

iTrader: (1)

sounds like an awesome project!

My buddy just picked up a ls6 for his 240sx project with 25k on it with the t56, pcm, harness, all accessories, pretty much a full pull out for $5,000 just to give you an idea

DMM

Might want to post this over in the "Tuning" section. I think the newer PCM/VCM's communicate on the serial data buss differently then they used to. I know the 04 would not work, but I think the 05 and later models are CAN systems so you may luck out with one of those.

Good luck!

icemanrd19

Ship your ls3 to dallas and let me use it on my 67

X715453

I would go to speartech.com and contact them. They seem to know alot about the Gen IV swaps.

yooperLS6

Give Brian a call at http://www.thomsonautomotive.com/?page=ads.cfm

aurora40

iTrader: (1)

Here's a thread you may want to read. Doesn't answer your question, but if it turns out you can't use the ECM, then it may be helpful:

https://ls1tech.com/forums/generatio...ls6-cts-v.html

scatillac

iTrader: (12)

IMHO, a more sanitary route would be to swap the LS3's 58X reluctor for a 24X reluctor since you'll have the pan off anyway and it's not too much more at that point to remove the crank. This will allow use of the LS6 ECM.

Your won't have to butcher your car's harness and the LS6 ECM will work just fine. Any competent tuner can put you right in business!

You'll have to retap the knock sensor holes to M10-1.5 and use LS1/6 knock sensors.

There are adapter harnesses available from several vendors on here that are cost effective and quick, but you can also fab them up yourself for a bit more time. I'll list the Katech part numbers since I have them handy.

- LS1/6 knock sensor and LS2/3/7 cam sensor adapter harness (KAT 4750)

- LS2/3/7 MAP sensor adapter harness (KAT-4751).

- 90mm TB adapter harness (KAT-4752) Do you have the gold blade throttle body? If so, ask about compatibility as these adapters were made for the LS2/7 silver blade versions and I'm not sure about the pinout on the newer (gold blade) version.

- You'll also need to buy or fab up some USCAR adapters for the LS3 injectors. The USCAR stubs, properly installed look much better than any the adapter harness.

- You'll be able to buy this stuff (and some ) and sell your LS3 harness for a substantial profit margin.

lollygagger8

iTrader: (7)

Did carfreak ever end up doing this??

family-man

do all LS motors share the same motor mounts locations on the engine?

07CTS-V

iTrader: (6)

Yes they do.

CGMLS3

iTrader: (4)

This is what I want to do in the near future. Let us know how it goes!

lollygagger8

iTrader: (7)

Did he??

I'm leaning towards going this route and want to hear about the probs/fixes and results!

veee8

iTrader: (40)

I ran the LS3 in my 04 for a while. Couple of notes...

The Gen IV computer and harness will not work with the caddy. You have to either swap the reluctor wheel or get a ligenfelter box for the crank signal. Then the LS6 computer can run it.
The gold blade LS3-LS7 throttle body can be used, but it is not right. All the fail safe drive by wire codes have to be turned off. The silver blade LS2 works better. The electronics are different.
The LS3 map sensor wont work with the LS6 computer. Doesnt matter if you get the adapter harness, it is scaled differently.
Injector adapters are required.
A complete tune is necassary.

BTW. I have sold the LS3 402, and am putting together a 427 LS7 with a 2.9L whipple on my V1.

lollygagger8

iTrader: (7)

Ok, so you need the reluctor wheel, LS2 TB, did you reuse the MAP from the LS6? Injector adapters, I've read something about retapping the block for misc sensors? What else am I missing? The LS6 flywheel and headers will bolt up to the LS3, right?

veee8

iTrader: (40)

Yes flywheel and everything will carry over.
I used the LS6 MAP. LS2 TB makes thinks easier. Injector adapters, and tapped the block for the knock sensors, with the appropriate wiring adapters.