Lean Cruise

[Pulse_GTO]

Wish there was a way to add it with hp tuners. My dad drives an 04 DBW 5.3. I turned LC on for it, but had to change it back. No cruise was not an option for him. Lol. Getting ready to do a 2000 mile trip in that truck, would be awesome to have LC and CC.

I would download the bin with PCMHammer, apply the patch with TunerPro, then do a write full flash with PCMHammer. Afterwards read the file in HP Tuners and the parameters you need to fine tune Lean Cruise are there in HPT. Just make sure that your dad's truck uses OS 12587603.

[ralmo94]

I would download the bin with PCMHammer, apply the patch with TunerPro, then do a write full flash with PCMHammer. Afterwards read the file in HP Tuners and the parameters you need to fine tune Lean Cruise are there in HPT. Just make sure that your dad's truck uses OS 12587603.

Thought about that but unfortunately I don't have any pcm hammer combat able equipment.

[Pulse_GTO]

Thought about that but unfortunately I don't have any pcm hammer combat able equipment.

I use an OBDX Pro VT. It shows in stock on the website and along with a micro usb cable I'm able to read an write at 4X with PCMHammer.

[brandongarnold02]

My 2 cents on Lean Cruise,
Take all this as not absolute fact, majority is not from my own personal experiance, but from hours and hours of reading things on the internet over the several years.

Lambda 1 stoichiometric 14.7 : 1 100% gas is the mixture that produces the most heat. Less fuel, less heat, More fuel, the fuel has a cooling effect to some degree.

Usually when people talk about running lean and doing damage, as far as I understand, it is mostly during a load that would require power enrichment and the cooling effect from the extra fuel, and possibly detonation. This is where the Cruise part of Lean Cruise comes in. During cruise conditions, there shouldn't be enough load to cause any damage to anything, assuming you have no knock.

People who talk about setting up carburetors for lean cruise, usually say lean it out until you get a little lean stubble, then either add a degree or two of timing, or go just a bit richer to eliminate the stumble. Every combination of vehicle and engine will want something a little different. Most LS engines I have read about, people seem to say that to lean negates any MPG benefit, and actuality uses more than leaving it stock. They usually don't say at what KPA they go from rich to lean though.

On flat ground, maintaining speed what KPA do you cruise at. What KPA does it idle at. If you are at 80 kpa most of the time, you probably wont see much improvement.
But you should be able to go fairly lean until about 70 or 75 kpa. If you look at a stock $OD bin on the Open loop AFR table, you can see that they have low load areas lean until around there. Of course it would never use that stock in closed loop, but gives you an idea of what GM thought was safe in the 90's. I think they have it set to around 16, or 16.5, or so. On your LS, I would take advantage of the spark adder table that adds or subtracts timing for deviations from stoich.
Be careful as I think most bins are set up for vacuum kpa, and not Manifold Absolute pressure. Big difference

Stock on a truck tune, I think it would be debatable how much damage you could cause running lean at high load, with the theory of less fuel is less heat, being that a stock truck tune usually doesn't take full advantage of Power enrichment. It is usually on a delayed timer and ramped in at a slow rate. I had a 2006 Dodge 1500, after looking at the tune in it, I seen it was set up to never engage PE unless It was floored TPS 100%. I pulled trailers to heavy for a half ton lots and lots of miles. It has close to 300K miles on it and it never melted anything. If the most heat is at stoich, this should have killed that engine if running lean would.

As far as how lean is safe, from what I know, leaner is safer, as long as there is no heat, or knock, detonation.

I've look at the holden stock lean cruise bits before, and thought they were a little conservative, I'm surprised you were getting 17:1 commanded with it, but its been a while since I looked at it. Did you notice any MPG improvement? Leaner doesn't always mean better mpg, because you loose a little power, and that increases load.
googling shows best Fuel economy at 15.8 - 17, depending on what chart you find.

If anyone wants to correct me on any of that, please do. I remember how hard it was to find anything on lean cruise when I would look the last couple of years.
I have gained so much from this forum I would like to be able to give some back. Hope that helps

I checked my data logs and on a steady 68 mph and my MAP sensor reading is sitting at around 55kpa at 16.9:1commanded afr. MAP kpa is around 30-35 at idle.

[brandongarnold02]

I use an OBDX Pro VT. It shows in stock on the website and along with a micro usb cable I'm able to read an write at 4X with PCMHammer.

I just ordered one of those yesterday. I’ve been using the obdlink sx. Kinda slow but gets the job done. I log with the PCM Hammer logger and create histograms with Megalogviewerhd. I also use the Universal Patcher because you can take the histograms and copy and past special into the tables on it. It’s just a little more difficult to maneuver through.

[joukoy]

I just ordered one of those yesterday. I’ve been using the obdlink sx. Kinda slow but gets the job done. I log with the PCM Hammer logger and create histograms with Megalogviewerhd. I also use the Universal Patcher because you can take the histograms and copy and past special into the tables on it. It’s just a little more difficult to maneuver through.

Good to know someone is actually using paste special :)
There is also histograms in UniversalPatcher:
Tuner -> right click table -> Show histogram
And logging is possible, too.

I hope you can test both features and give feedback.

[ralmo94]

Sounds like low enough load to possibly benefit from LC. What map does go back to stoich?
I don't think I would go any leaner, at least without a wideband to verify it's mixing fuel as desired.
I wouldn't make any changes until you verify the improvement for a whole fill up.
What was your baseline mpg?

[brandongarnold02]

Good to know someone is actually using paste special :)
There is also histograms in UniversalPatcher:
Tuner -> right click table -> Show histogram
And logging is possible, too.

I hope you can test both features and give feedback.

I have actually used Universal Patcher logger quite a bit the 3 weeks I was getting some irregular jumps in rpm readings sometimes. Let’s say I’m running a constant 1500rpm I would get quick spikes up to 8000rpm in the log. I am thinking it’s because I’m using the obdlink sx and it can’t keep up because when I'm using the PCM Hammer logger the data all freezes under acceration. When the obdx pro vt I ordered come in hopefully it will prevent these logging issues. I knew there was some kind of histogram stuff on there but wasn’t sure how to use it plus I got the Megalogviewerhd before I started looking at universal patcher so it’s been my go to plus I have the math set up for all my tables already. I will definitely be checking out the historgram creator on there. Actually Universal Patcher has quite a bit more capabilities than TunerPro.

[joukoy]

I have actually used Universal Patcher logger quite a bit the 3 weeks I was getting some irregular jumps in rpm readings sometimes. Let’s say I’m running a constant 1500rpm I would get quick spikes up to 8000rpm in the log. I am thinking it’s because I’m using the obdlink sx and it can’t keep up because when I'm using the PCM Hammer logger the data all freezes under acceration. When the obdx pro vt I ordered come in hopefully it will prevent these logging issues. I knew there was some kind of histogram stuff on there but wasn’t sure how to use it plus I got the Megalogviewerhd before I started looking at universal patcher so it’s been my go to plus I have the math set up for all my tables already. I will definitely be checking out the historgram creator on there. Actually Universal Patcher has quite a bit more capabilities than TunerPro.

Sounds like a bug: There should be no spikes even if there is communication problems.
If you want to help fixing this, enable debug log on patcher window, run log until you get this spike and send both: debug log & data log by email.
joukoy at gmail.com

[brandongarnold02]

Sounds like a bug: There should be no spikes even if there is communication problems.
If you want to help fixing this, enable debug log on patcher window, run log until you get this spike and send both: debug log & data log by email.
joukoy at gmail.com

I just sent you a debug log and a data log.

[joukoy]

I just sent you a debug log and a data log.

Thank you!

[joukoy]

I just sent you a debug log and a data log.

I can see from logfiles, you are using old version. Please download latest zip from github and try again, bug should be fixed already.

[ralmo94]

Brandongarnold02,
Where you ever able to verify fuel economy improvement with lean cruise?

[brandongarnold02]

Brandongarnold02,
Where you ever able to verify fuel economy improvement with lean cruise?

It actually seemed to decrease my in town fuel economy by about 3/4 of a gallon per mile. Went from 10.5 to 9.75. That’s with is leaning out to 16.5 to 1. Leaning out to a bit over 17 got me only 9.25 mpg. I turned off lean cruise and going to retest then may advance timing some after that and see if that increases fuel economy.

[ralmo94]

It actually seemed to decrease my in town fuel economy by about 3/4 of a gallon per mile. Went from 10.5 to 9.75. That’s with is leaning out to 16.5 to 1. Leaning out to a bit over 17 got me only 9.25 mpg. I turned off lean cruise and going to retest then may advance timing some after that and see if that increases fuel economy.

Is your tune spot on? Lt &St fuel trim within -5 to 0?
If so, I would try going a little richer about 15.8 and see what it does.
Spark definitely, there should be a segment to add or subtract acourding to fuel mixture.
Leaner mix needs more time to combust. If that's not already on I would definitely do that.