I've got a 2002 5.3 Suburban that get about 15 mpg and I've been looking into lean cruise. I've got EFI live, but am still a little new at it. I had my dyno tuner help me tune it today and we picked up about 10-15ft/lbs from a tune alone, but didn't mess with lean cruise yet. What AFR's should I be at while cruising and what kind of timing should I be at. What else should be changed? Anyone have a tune they'd like to share to get me started.

 

I dont know for sure but even though the tables are there lean cruise is locked out from GM (meaning it wont do anything no matter what you do). Im guessing with EFI live you can get around that with a COS, something HPT cant do!!!!

 

Yeah, I already know I have to do a custom operating system.

 

Its not a COS but a patch, Corey made a thread about it a while back:
https://www.performancetrucks.net/fo...d.php?t=438687

EfiLive forums have a lot of info on it too, I don't know too much about it though since I use HPT.

 

I haven't look into this at all and I've got HPT, but I downloaded the Beta the other night and there are tables and options for lean cruise and transient fueling. Any idea if this is just for show or can HPT now change this stuff?

 

In HPT the tables are there but are locked out in the PCM for US cars. There is a way to do it with HPT but only with straight SD tuning...haven't looked into it much but there is info in the HPT forums.

 

I had a tuner enable it on my 03 Silverado today. He was using HP tuners.

 

So what is your wideband reading while your "lean cruising"?

 

I see 14-15.8 at times of steady throttle under 2k rpms

 

I don't have a wideband, he set it up for 16.3 when "lean cuise" is active. It comes on when fully warm,on at 35mph, and off at 30mph. If you accelerate during lean cruise it goes to a preset air fuel.