LS3 into 03 Z06 - Starts and dies IMMEDIATELY - Help??

[ROBRAYMER]

Doesn't even attempt to keep running. This is a brand new crate LS3 with an LS2 TB conversion, stock 03 MAF, and approximately a .600 lift cam, LT's, etc. Did all the basic changes for typical cam'd LS engines, and changed the ETC Scaler to 0.0192 (which made no difference at all from the stock 0.0255). Actually, nothing seems to make any difference with the start-up....i.e. timing, fuel, airflow tables, etc. Only need to hold the idle up for about 10 seconds after it starts, then EASE off the pedal and it runs and idles fine. But NEVER EVER starts and runs on it's own without "helping it". Just starts and dies IMMEDIATELY.

No logs or tune files with me right now, but will have them in an hour or so. Just really wondering if there are any other "basic" things that need to be changed in the intial tuning that would be affecting the start-up?? I tune these cars every day, but this is the first LS3 into an 03 Z06 I've played with. I'm stumped!

Has anyone done tuned a similar conversion?

Thanks in advance for your help.

[JoeyJoeJoe]

Make sure you have the right cam/crank reluctors in the engine. LS1/6 use a 24x/1 and LS3 use a 56x/4. You will have hard starting if they are not correct. If you have the stock LS3 stuff, Lingenfelter used to make a conversion box. Not sure if they still do or not.

[Throttle]

idle airflow needs to be corrected.then ve at idle.

[blownbluez06]

Did you change OS's, copy anyone's tune or are you trying to do this in speed density mode?

Try going into the system tab and disabling VATS.
Then if you're doing speed density, pull your codes and make sure the P0102 and P0103 codes are set. If not, it will kill your ability to start the car.

[alextzi]

What PCM are you using, if it is an LS3 PCM that has a LS3 card style MAF data programmed into it, it wont run with an 03 older style MAF, the frequency curves are way different.

Try running in speed density mode to get up an running (disable MAF).

[kyphur]

I have an LS3 in my 01 with an 01 PCM. IIRC the pcm from mine to yours is pretty similar.