Another Lean Cruise Thread

[MaroonMonsterLS1]

Most of the lean cruise threads I've found are back from like 2004 or 2005. They prettymuch said the EPA was the roadblock and HPtuners didn't want to try and piss them off (I can't really say I blame HPT for their decision)

Have we found a good way around this yet? Can we enable this anyway now that it's 10+ years later? I'm curious if we can move over to an Aussie OS to get around the US hard block in the code? or maybe canadian?

Or has HPT stuck to their guns and still tell the users to pound sand when it comes to the lean cruise tables? If that is the case, again, I can't really blame them but I hope like hell we can start using the lean cruise.

[2xLS1]

Look for posts by Mike454SS in this thread. He says how to do it changing the platform code.
https://ls1tech.com/forums/pcm-diagn...an-cruise.html
I haven't tried it that way because I can do it by changing the code with another tuner package. Don't expect much gains in MPG as I've tried it on my 04 Silverado with a 4.8L and other than seeing the leaner commanded A/F in the scanner the MPG didn't change if at all. And you have to add the timing when in LC to get any advantage.

[Area47]

it was active on a 5.7 gto i did a while back. it shut off the o2 feedback and ran at 15.5 afr under part throttle.

[2xLS1]

it was active on a 5.7 gto i did a while back. it shut off the o2 feedback and ran at 15.5 afr under part throttle.

Because the 04 GTO was basically an imported Holden and LC apparently slipped through the crack and didn't get disabled before import. That's been pretty well known for a while.

[Fast4.7]

I had it enabled in my Express vans 0411. Ran 17:1 at 3,000 rpm with 52? of timing. 19 mpg @ 70 mph despite the 4L85E and 4.56 gears in the 9.5" 14-bolt.

[dmaxs10]

Sub to see what everyone is running for afr and timing. I changed the code running 16 or 16.5 afr and 45* gain 2 mpg in my 5.3 s10

[Jim Brown]

This is a very interesting discovery for me.
Although, I don't think it is actually related to the VE tuning problems I've been having.
My Commanded AFR does NOT change though, and yet my Wide Band shows the mixture going all the way to 18:1
(full scale), (these problems are all at highway speed/steady cruise conditions),
and the Long Term Fuel Trims are going crazy trying to go over 10-15% richer.....
But then it stops, and gradually all the LTFT numbers go back to less than 3%, (most are less than 1%).
I have also had the opposite occur 5 or 6 times now, the AFR gradually goes full scale RICH at cruise (10:1).
This was going on before I purchased HPTuners, but I didn't know what the problem was, and I was getting instant
random misfire codes..... I thought it was the ignition, which is now all brand new, including the distributor.
I know what I'm doing with Mega-Squirt, but HPTuners and the 0411 are new to me, and it didn't occur to me,
until I found this post, that I have an Ignition Advance adder Table, but no way to change commanded AFR,
other than various adders and multipliers and qualifiers.
Could this be related to the "hidden" lean tables you are referring to ??

Jim

[Jim Brown]

I think I may have finally found the solution.
There are quite a few "testing routines" that run automatically, which are sometimes controlled by the settings in
"Engine Diagnostics" -- "DTCs", that can be seriously disrupted by other tuning changes or conditions.
A likely culprit is every one of the Oxygen Sensor diagnostic routines, which take control of the injectors to run tests,
making the engine "temporarily" full lean or full rich, (10:1 to 16:1), off the scale on my wide band,
while the commanded AFR sits there at 14.7 with black smoke coming out of my tailpipes at 80 mph, and
the long and short term fuel trims are going apeshit and ruining the usefulness of my recorded scan.
This is not a verified fix yet.
I will post back in a day or 2 with results.