This script is the one I came up with to give the later model OS the lower 600 idle like the 01-early 02's had.
LB7: 600 idle speed
- Thread starter THEFERMANATOR
- Start date
This script wouldn't run on my OS (15189044). But, I was able to do what you said and hand-copy the idle tables from a 2001 OS to my 2003 OS, and it worked great. Thanks for telling me how to get it to work right!
Also, I attached the script for anyone who has a late-LB7 OS and doesn't want to do it by hand.
Also, I attached the script for anyone who has a late-LB7 OS and doesn't want to do it by hand.
Thats wierd, this script is off of a late 02(6006). I just ran it over an 044 that I have and it worked fine. I also tryed it on an LLY and it worked fine. I know it won't work correctly on an early 02 or older though.
Oh, LOL, I just figured it out!
Your EFI is set to American units, I do all my tuning in metric. I didn't think about the coolant temperature axis being in the wrong units.
So, for the record, your script is Imperial and mine is Metric.
Now I feel dumb
Your EFI is set to American units, I do all my tuning in metric. I didn't think about the coolant temperature axis being in the wrong units.
So, for the record, your script is Imperial and mine is Metric.
Now I feel dumb
Low Idle Surge Fix!
Well, after lowering my idle, my truck would surge badly if I gave it a little gas then hit the brakes (like pulling forward a few feet at a drive-through). It would push through the brakes if I wasn't careful. Not good. Since I was using a 2003 OS and 2001 values, I figured they made some changes to the way the OS interprets the tables. But, rather than be defeated and return my idle to 680, I found a solution!
This solution is probably only needed on the later (2003) operating systems (or if your vehicle is surging with a lower idle). The plus side of this is it appears you can now set the idle to any speed you want (although my truck lopes below ~550 RPM) without worrying about the surge/glitch.
First, set your idle table {B0701} to where you want the truck to idle. I leave the idle alone until the coolant hits ~110°F since it seems to warm up faster that way, but it's up to you. Personally, I prefer the very early 2001 values (from OS 15063376).
Next, adjust the idle/run mode table {B1201} to compensate for the new idle speeds. I had good luck setting the idle/run mode cells to about 30-50 RPM lower than the idle speed cells. You might have to make some slight fine-tuning here. If you copied an early stock tune for the idle speed, just copy this table too, they should be pre-adjusted.
Finally, alter your "{B0756} Idle Mode Fuel Quantity (Moving)" so it goes 7, 8, 8, 8, 6, then all 5's for the rest. This was the source of the surge in my truck. When I would give it a little gas, then hit the brake, the truck would look in this table to see how much fuel to give the engine while it returns to idle. The factory 3 mm3 was not enough with the lower idle, and would cause the engine to stumble then surge. However, 8 mm3 is enough to make it return smoothly to idle, just like stock. You may have to play with this value a little bit depending on how loose/tight your torque converter is.
To simplify the process, I created a script that sets your idle to stock early-2001 LB7 values, and fixes the surge. The script will run on either Metric or Imperial units just fine due to clever hand-editing! So, it should work on all the late-LB7 operating systems.
If you try this, please let me know the results. It seems to work great on my truck, and I believe it should work on other LB7's.
Well, after lowering my idle, my truck would surge badly if I gave it a little gas then hit the brakes (like pulling forward a few feet at a drive-through). It would push through the brakes if I wasn't careful. Not good. Since I was using a 2003 OS and 2001 values, I figured they made some changes to the way the OS interprets the tables. But, rather than be defeated and return my idle to 680, I found a solution!
This solution is probably only needed on the later (2003) operating systems (or if your vehicle is surging with a lower idle). The plus side of this is it appears you can now set the idle to any speed you want (although my truck lopes below ~550 RPM) without worrying about the surge/glitch.
First, set your idle table {B0701} to where you want the truck to idle. I leave the idle alone until the coolant hits ~110°F since it seems to warm up faster that way, but it's up to you. Personally, I prefer the very early 2001 values (from OS 15063376).
Next, adjust the idle/run mode table {B1201} to compensate for the new idle speeds. I had good luck setting the idle/run mode cells to about 30-50 RPM lower than the idle speed cells. You might have to make some slight fine-tuning here. If you copied an early stock tune for the idle speed, just copy this table too, they should be pre-adjusted.
Finally, alter your "{B0756} Idle Mode Fuel Quantity (Moving)" so it goes 7, 8, 8, 8, 6, then all 5's for the rest. This was the source of the surge in my truck. When I would give it a little gas, then hit the brake, the truck would look in this table to see how much fuel to give the engine while it returns to idle. The factory 3 mm3 was not enough with the lower idle, and would cause the engine to stumble then surge. However, 8 mm3 is enough to make it return smoothly to idle, just like stock. You may have to play with this value a little bit depending on how loose/tight your torque converter is.
To simplify the process, I created a script that sets your idle to stock early-2001 LB7 values, and fixes the surge. The script will run on either Metric or Imperial units just fine due to clever hand-editing! So, it should work on all the late-LB7 operating systems.
If you try this, please let me know the results. It seems to work great on my truck, and I believe it should work on other LB7's.
I'll have to try this out. Mine will do this on my DSP2 only when cold, but the regular side never does it.
If you like your idle speeds, then you might want to just alter the {B0756} table manually, since my script will overwrite the idle speed with 2001 values. It looked like you used 2002 idle speeds on yours.
Mine was set to a 600 idle speed which was only used in 01 and a few 02's. The 680 idle didn't agree with my brakes trying to stop.
I'm new to diesels and I know that this will sound really stupid, but what is the benefit of lowering the idle RPMs (other than less fuel consumption)?
Actually the 680 idle is quieter and a bit smoother I found. I did it because my BURB has anemic brakes compared to the GMT-800 platform, and I got tired of having to stand on the brakes so hard to slow down the last 20 MPH or so. At a 680 idle she would push through the brakes if you didn't plant your foot on em, but at 600 she stops easily.
Just FYI, for some that are having trouble with scripts....
We are talking like 2 tables here...And only a couple parameters within those tables...Why a script? lol.
Seems like much when you can just go to your tables and make 2 quick adjustments in the ECT area you want it to idle at desired...lol.
We are talking like 2 tables here...And only a couple parameters within those tables...Why a script? lol.
Seems like much when you can just go to your tables and make 2 quick adjustments in the ECT area you want it to idle at desired...lol.
That's weird, mine idles what seems like 25% quieter at 600 than at 680... And after altering the moving fuel quantity, 600 is just as smooth for me. But I know what you mean about the brakes, my 1982 is the same way.
That is quite true, which is why I explained what tables to change and how.
However, I put the script up for convenience. The way I wrote my script, it works on Metric or Imperial units
It takes only a minute or two to change your idle speed, but only a few seconds to download and apply the script.I was just trying to help, lol :hug:
It was easier for me to just compare the 2 and make a script as that only took me about 30 seconds to do.Just FYI, for some that are having trouble with scripts....
We are talking like 2 tables here...And only a couple parameters within those tables...Why a script? lol.
Seems like much when you can just go to your tables and make 2 quick adjustments in the ECT area you want it to idle at desired...lol.
Fully understand, the last thing I wanted is to make it sound like it wasnt a good idea lol You did help.That's weird, mine idles what seems like 25% quieter at 600 than at 680... And after altering the moving fuel quantity, 600 is just as smooth for me. But I know what you mean about the brakes, my 1982 is the same way.
That is quite true, which is why I explained what tables to change and how.
However, I put the script up for convenience. The way I wrote my script, it works on Metric or Imperial units
I was just trying to help, lol :hug:
I was only pointing out some people have difficult using a script and that the changes were so simple, that for some guys having issues they could make the changes without the script. Hope you guys weren't taking offense to my post, just trying to help too.
Yeah, no offense taken. I totally see how scripts are overkill for this, but I need all the practice I can get with them :spit:Fully understand, the last thing I wanted is to make it sound like it wasnt a good idea lol You did help.
I was only pointing out some people have difficult using a script and that the changes were so simple, that for some guys having issues they could make the changes without the script. Hope you guys weren't taking offense to my post, just trying to help too.
That is odd, I have only ever had it get quieter as the idle speed is decreased. I noticed it and started implementing it in my tunes When I noticed that my parents '02 was substantially quieter than my '04 or buddies '03. But then again, every truck is different.
That is odd, I have only ever had it get quieter as the idle speed is decreased. I noticed it and started implementing it in my tunes When I noticed that my parents '02 was substantially quieter than my '04 or buddies '03. But then again, every truck is different.
Probably has something to do with the sound deadining pads that mine doesn't have. The newer trucks had quite a few things in them that blocked out extra engine noise VS my BURB.
This sounds great, as my brakes are like yours fermanator they suck at low speeds. Does anyone think this will have any long term effects on the motor? Like will it be harder for the balance rates to keep the engine running smooth or anything like that?