There's been some interest in the Highway Lean Cruise for the 1227747 ECM so I figured I do a how to.
From the factory the 1227747 ECM had a highway lean cruise option but GM had to turn it off because it was not in line with EPA regulations at the time. I had read some archives at DIY-EFI about this subject and I don't know who or which group of EFI pioneers to give credit to.But way back when Robert Rauscher aka RBob 10/30/2000 wrote a DOS version to make the needed changes to a 7747 bin file, then rewrote the application file for windows. I had to make a few changes so it would work up to Windows 7 through Command Prompt. RBob gets all the credit for this. I am just writing up a how to use the program he wrote.
At the end of this thread I will include the Zip file with all that is needed in it. There is a Read Me First, Read Me HIWAY747 and a Read Me ESC Done file that you should read and has information on what these patches do. There is also a XDF with all parameters needed.
Note: Use at your own risk. I am not responsible if you melt your engine. Go slow when tuning!!!
That said when this patch is installed most settings are done on the conservative side except Highway Spark is untouched.
This patch piggy-backs onto the hi-way spark advance code that is already present in the '747 ECM. In order for hi-way SA to be enabled, the ESC test must have already been successfully completed. If the timer @ 0x025 is set to greater then zero, the ESC test is also required for hi-way fuel to be enabled.
I think the easiest way for people today is to first find the command prompt on your computer. Windows 7 go to Start, All Programs, Accessories then command prompt and click on it to see where you are. Usually users/your name. If you know DOS ship next few steps and make a folder anywhere you want.
Go to that folder. In this case it would be C:\ Users\EagleMark and make a folder called "HiWay" or whatever you want. Then type chdir HiWay and click enter. Poof your in that folder.
Download the Zip folder at bottom of this post, right click save target as and put it in that folder, then unzip it there.
Next copy your bin file from a 1227747 ECM and paste it in that folder, rename it to something simple like asdu.bin. Always save an origanal copy of your bin.
Here's what I used.
ASDU-$42-5.7L-Auto.bin was my origanal.
asdu.bin was the copy I used in the HiWay enable program.
ASDU-$42-5.7L-Auto-Hiway.bin was what I saved the file to.
You'll notice in command prompt the "0" in command prompt has a dot in center or a slash through it, this is a zero. If you typed "O" the letter it would not have a dot or slash through it.
Here is the command: s19_pat_ HIWAY747.s19 0xD000 file2bepatched.bin
Must be exact including underscores, spaces, zeros, small letter x capital D and the exact name of your bin file to replace file2bepatched.bin
Now you have everything you need in the same folder so type in the command in the picture below and hit enter.
That has made the changes needed to the bin file. Rename it to asdu-hiway.bin Open TunerPro and click on Tools, then Difference tool and find the original bin file and the one you changed and renamed asdu-hiway.bin or whatever in the compare box and hit OK. The Difference window will open, make sure you have the original in one side and the hiway in the other and click search. You should see 48 bytes difference.
Your bin is now highway cruise enabled.
Next open the modified bin in TunerPro and see the differences made, although some are there to begin with they are not enabled. You can see a couple differences made in this picture with the compare bin. One thing to notice is there was no Highway Spark added! This was probably done as a safety factor so people don't just do this without testing on a untuned, low fuel pressure, over timed or just plain bad running rig.
I know my Suburban is well maintained and the tune is spot on. So far I have added 3 degrees across the board on this table and have no knock. This was tested on flat land which runs into mountain passes and I can watch the MAP kpa go above what's listed and it will go closed loop for a bit until parameters are met and go back into Highway Cruise. No knock. I'd like to find an F body bin that had this feature enabled from the factory and see how much timing they add? Although I don't think my Suburbans weight and wind Resistance could handle as much as a Camaro...
This next patch sets the status bit as though the ESC test for knock has already been run. This allows PE SA and Hiway SA to occur without having the knock test run.
This patch also bypasses the temperature and time delay window for PE mode.
That's it for me tonight. Stay tuned and we will go over the next patch in this Zip folder.
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