Need help setting idle on ls3

[Kqrouth]

I have an 2001 extended cab gmc with a high output ls3. I have a truck intake and 92 mm throttle body and I need help finding a tune because on a cold start it will die over and over. I think the throttle body isn't giving enough air on idle but if anybody has a good solution please let me know and thanks.

[joecar]

Hi Kqrouth,

Do you have the ECM that came with the LS3...?

This thread may help: http://forum.efilive.com/showthread....38-idle-tuning

[Kqrouth]

No I'm running a ls1 ECM, could that be a problem??

[WeathermanShawn]

If you have not read through the LS1 Idle Tutorial this might be a good time to do it..http://forum.efilive.com/showthread....ips-amp-Tricks

I don't have a lot of advice on differing TB sizes, but you might find some hints in the Tutorial or Thread.

Check it out..

[Kqrouth]

Alright I'll look I to that. And we are about to put a dyno in our shop could that help with making the overall tuning easier?

[WeathermanShawn]

Alright I'll look I to that. And we are about to put a dyno in our shop could that help with making the overall tuning easier?

Absolutely!

[5.7ute]

Electronic or cable TB?
Using the earlier pcm will not be an issue as long as the necessary hardware changes have been made.(either the convertor box or reluctor etc)

[eficalibrator]

First things first... Do you have good air-fuel ratio control? The LS3 is VERY intolerant of lean conditions at idle and will misfire significantly with as little as 5% lean of stoich. Poor AFR control would be a symptom of either improper injector characterization or airflow mapping.

[Kqrouth]

Okay good cause I've just started with the tune and I've heard that the idle is the hardest thing to get right so mabe after that it will be easier.

[Kqrouth]

Cable TB and yes I've made all the changes.