Tylluc20

Ok so recently purchased Gm's Ls3 crate motor with its plug and play harness and accessory drive kit, the previous ls1 was blown up and far beyond a rebuild. So the mechanical part of the swap has been great, mounted right up to the tranny and k member. But I am running into electrical problems at my point in the build, the harness is hooked up great but I have no idea how the standalone computer system that came with the ls3 will communicate with my 99 dash gauges, Tach, Oil pressure, Coolent temp, ect. From the research i have done i am assuming that i just have to buy Aftermarket gauges to read oil pressure, which i am most concerned about because of start up. Also i have not connected the old battery harness to a fresh battery, but i am assuming that it will just crank the starter over with no modifications to the ignition system. Any help/advice is greatly appreciated as i am at a stand still in my build atm.

AgFormula02

iTrader: (13)

Use stock pcm and harness, a lingenfelter 52 to 24 converter, and some small changes and you should be up and running.

Trying to run the new pcm and integrating it into the car will be very time consuming.

Tylluc20

The problem is that my step dad ending up selling the old harness( Dont ask me why) so im stuck with what i have right now

Need4Camaro

iTrader: (1)

I'd contact Speartech in that case, either way at this point you're going to pay $$$ to integrate the LS3 stuff into the 99 - far from compatible without serious reworking. Actually there was a place I saw that still sells our stock harness brand new, its like $800 but for peace of mind its well worth it IMHO. I'll try to locate it for you.

Dirty Vegas

iTrader: (12)

You might want to repost this in the conversion/swap section of the forum. You'll get better visability and replies to this kind of problem. Hopefully they can get you pointed in the right direction on the cheap!