Gen4 tuning help
Gen4 tuning help I just finished up doing my swap into my 70 monte carlo a month back and I'm running into some tuning issue's that's I'm having trouble ironing out. Specs on my setup is L96 2014 motor, 08 4L80, E38 pcm/T42 tcm with a 08 2500 van file as my base file. Running the stock #50 injectors that came with the motor and vvt is disabled.
Issue's I'm running into is high idle when you let of the gas and coast, plus when you come to a stop it holds the idle and slowly comes down. And if you let off the brake and coast the idle goes right back up again. I'm a little new to the gen4 stuff so not sure what tables control that (I have no throttle cracker tables)
Second issue is when warming up the engine, when cruising steady will surge up and done a little. Can hear it in the exhaust and feel it. Once fully warmed up the issue mostly disappears but you can faintly notice it still on the expressway.
Third issue is the trans. I'm having issue's still getting the trans to do what I set in the tables for pressure. Most of the time the trans shifts ok, not great or solid like I would like to see. But every once in a while when I start it and drive down the start the trans will go full pressure slamming every gear. Only way it stops is if you cycle the engine on/off and then drive again, then things return to normal. Torque management is mostly off and shift times are at .2 with shift pressure raised a decent amount.
Any help or direction would be great, I'd love to finish up to the tune so I can take it to the track once before the snow flies this year
Issue's I'm running into is high idle when you let of the gas and coast, plus when you come to a stop it holds the idle and slowly comes down. And if you let off the brake and coast the idle goes right back up again. I'm a little new to the gen4 stuff so not sure what tables control that (I have no throttle cracker tables)
Second issue is when warming up the engine, when cruising steady will surge up and done a little. Can hear it in the exhaust and feel it. Once fully warmed up the issue mostly disappears but you can faintly notice it still on the expressway.
Third issue is the trans. I'm having issue's still getting the trans to do what I set in the tables for pressure. Most of the time the trans shifts ok, not great or solid like I would like to see. But every once in a while when I start it and drive down the start the trans will go full pressure slamming every gear. Only way it stops is if you cycle the engine on/off and then drive again, then things return to normal. Torque management is mostly off and shift times are at .2 with shift pressure raised a decent amount.
Any help or direction would be great, I'd love to finish up to the tune so I can take it to the track once before the snow flies this year
TECH Regular
Joined: Jun 2012
Posts: 414
Likes: 5
From: SV, AZ
Both problems you describe could be either air/fuel or timing related or a combo of both. My bet for the idle issue would be timing. The surging is harder to nail down. Are you running open or closed loop?
Or he could calibrate it for what the car actually wants instead of just guessing.... dunno.
Both problems you describe could be either air/fuel or timing related or a combo of both. My bet for the idle issue would be timing. The surging is harder to nail down. Are you running open or closed loop?
Both problems you describe could be either air/fuel or timing related or a combo of both. My bet for the idle issue would be timing. The surging is harder to nail down. Are you running open or closed loop?
no, he meant VVE. VVE are virtual volumetric efficiency equations and are used in e38 operating systems. You need to change your OS thats why you see those issues. You can try messing with the throttle follower tables, but you need a different OS. Had this happen countless number of times.
Well I'm very limited on what OS's I can use with my combo. e38/t42 combos need matching hardware to run my 4l80 and think 08 was the first year. What OS would you suggest? And what's the difference a new OS would help me with?
Trending Topics
who told you that lie? The TCM has its own OS. If you attempt to read a e38 with the TCM disconnected, the downloaded file won't have any trans parameters. The same happens if you have ANY e38 and hook up a T42 with an 80e segment, then proceed to download the file, you'll end up with the e38 OS and the 80e segment combined in the final downloaded file. I've done it in at least 20 vehicles.
You can also modify the harness for control the 80e with a 60e segmented T42.
So no, you're not limited on the OS. Just trying to give you a heads up. 1st rule if you want help is post the HPL and HPT file.
Is it cammed? is it stock? need more information. Seems like its stock, if it is, then i can assure you its an OS issue, you could find some alleviation by manipulating the idle timing tables and the area effective size of the throttle body. But it is just a bandaid.
You can also modify the harness for control the 80e with a 60e segmented T42.
So no, you're not limited on the OS. Just trying to give you a heads up. 1st rule if you want help is post the HPL and HPT file.
Is it cammed? is it stock? need more information. Seems like its stock, if it is, then i can assure you its an OS issue, you could find some alleviation by manipulating the idle timing tables and the area effective size of the throttle body. But it is just a bandaid.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
If he didnt setup the fuel tables properly i agree with you. Bad IFR will cause a hanging idle because the torque calculations would be off. But ive had the instance of different throttle bodies having different maps and ultimately having a hanging idle. Could be, or not. Im sure though, if he uses a l96 e38 oem OS from that year along with the proper IFR, the issues would be fixed (if its stock). If not then that goes out the window and just needs a plain tune. Lol.
who told you that lie? The TCM has its own OS. If you attempt to read a e38 with the TCM disconnected, the downloaded file won't have any trans parameters. The same happens if you have ANY e38 and hook up a T42 with an 80e segment, then proceed to download the file, you'll end up with the e38 OS and the 80e segment combined in the final downloaded file. I've done it in at least 20 vehicles.
You can also modify the harness for control the 80e with a 60e segmented T42.
So no, you're not limited on the OS. Just trying to give you a heads up. 1st rule if you want help is post the HPL and HPT file.
Is it cammed? is it stock? need more information. Seems like its stock, if it is, then i can assure you its an OS issue, you could find some alleviation by manipulating the idle timing tables and the area effective size of the throttle body. But it is just a bandaid.
You can also modify the harness for control the 80e with a 60e segmented T42.
So no, you're not limited on the OS. Just trying to give you a heads up. 1st rule if you want help is post the HPL and HPT file.
Is it cammed? is it stock? need more information. Seems like its stock, if it is, then i can assure you its an OS issue, you could find some alleviation by manipulating the idle timing tables and the area effective size of the throttle body. But it is just a bandaid.
Good to know info though, I'm new to the ls gen4 stuff so learning as I go.
I'd post the file but I use tunercats so I don't have a .hpt file to post. I might be able to convert it to a .bin but that's it. Motor is completely stock except headers, maf is a ls7 and gas pedal is a C6.
So by what your saying I could use my stock e38 pcm from my 2014 l96? The t42 will function correctly as long as I match the vins right?
who told you that lie? The TCM has its own OS. If you attempt to read a e38 with the TCM disconnected, the downloaded file won't have any trans parameters. The same happens if you have ANY e38 and hook up a T42 with an 80e segment, then proceed to download the file, you'll end up with the e38 OS and the 80e segment combined in the final downloaded file. I've done it in at least 20 vehicles.
You can also modify the harness for control the 80e with a 60e segmented T42.
So no, you're not limited on the OS. Just trying to give you a heads up. 1st rule if you want help is post the HPL and HPT file.
Is it cammed? is it stock? need more information. Seems like its stock, if it is, then i can assure you its an OS issue, you could find some alleviation by manipulating the idle timing tables and the area effective size of the throttle body. But it is just a bandaid.
You can also modify the harness for control the 80e with a 60e segmented T42.
So no, you're not limited on the OS. Just trying to give you a heads up. 1st rule if you want help is post the HPL and HPT file.
Is it cammed? is it stock? need more information. Seems like its stock, if it is, then i can assure you its an OS issue, you could find some alleviation by manipulating the idle timing tables and the area effective size of the throttle body. But it is just a bandaid.
If he didnt setup the fuel tables properly i agree with you. Bad IFR will cause a hanging idle because the torque calculations would be off. But ive had the instance of different throttle bodies having different maps and ultimately having a hanging idle. Could be, or not. Im sure though, if he uses a l96 e38 oem OS from that year along with the proper IFR, the issues would be fixed (if its stock). If not then that goes out the window and just needs a plain tune. Lol.
IFR seems good. I scaled it for the #50 injectors. I'm betting your correct though since all the sensors are 2014 and tables are 2008. I did keep the oem 2014 l96 e38, I could swap that in the vehicle and get a base tune with IFR's set and see.
You can't use the 2014 e38, in order to make all the swaps work you have to use ecm/Tcm combo that was in a factory vehicle. Far as I know there are no 2014 E38/T42 combos so it won't work. You can't just flash a E38 to any year.
Staging Lane
Joined: Oct 2012
Posts: 54
Likes: 1
From: Calgary Alberta Canada
When did I mention guessing there genius? I suggested trying adjusting minimum air (which probably causes 80% of the idle issues on gen 4's) to see if it helps. He doesn't sound experienced so I gave him a value to try first.
Did some more checking and found my surging issue. I noticed when the car came to a stop and idled for a few minutes,the trans would engage something quick while sitting. (Felt like the car got pushed from the rear) Had a gut feeling it was the TCC so disabled any engagement completely and the surging disappeared.
Drives much better and rpms are steady now.
So I noticed in my tables a setting for max TCC limit torque was set to 0 stock. From what I can make sense of this 0 means no torque is allowed to TCC. When I compared to one of my other 4l80 files the setting was maxed out to 6042. I'm guessing the maxed out setting means its disabled and 0 means it's not letting the TCC engage. Any thoughts?
Also on a side note separate from the TCC is the maf readings while driving. I'm using a LS7 card style maf and have a diverter screen in front of it. I've noticed up to 200-300 hz fluctuation of the maf while driving steady. I have read on other sites of people having similar issue's and having to put a second diverter screen after the maf too to keep turbulence down. Any thoughts on this too?
Drives much better and rpms are steady now.
So I noticed in my tables a setting for max TCC limit torque was set to 0 stock. From what I can make sense of this 0 means no torque is allowed to TCC. When I compared to one of my other 4l80 files the setting was maxed out to 6042. I'm guessing the maxed out setting means its disabled and 0 means it's not letting the TCC engage. Any thoughts?
Also on a side note separate from the TCC is the maf readings while driving. I'm using a LS7 card style maf and have a diverter screen in front of it. I've noticed up to 200-300 hz fluctuation of the maf while driving steady. I have read on other sites of people having similar issue's and having to put a second diverter screen after the maf too to keep turbulence down. Any thoughts on this too?
TECH Regular
Joined: Jun 2012
Posts: 414
Likes: 5
From: SV, AZ
When you randomly pulled 10-15% out of your butt, genius. Sure glad you're here to make up random statistics and suggest random values to use.
I narrowed it down the idle issue to my adaptive idle control. THe speed for it is set to 1.2mph and that's exactly when the motor rpm picks up. What tables are related to the adaptive idle enable?
Also like I mentioned in my last post, anyone have any ideas on this?
"Did some more checking and found my surging issue. I noticed when the car came to a stop and idled for a few minutes,the trans would engage something quick while sitting. (Felt like the car got pushed from the rear) Had a gut feeling it was the TCC so disabled any engagement completely and the surging disappeared.
Drives much better and rpms are steady now.
So I noticed in my tables a setting for max TCC limit torque was set to 0 stock. From what I can make sense of this 0 means no torque is allowed to TCC. When I compared to one of my other 4l80 files the setting was maxed out to 6042. I'm guessing the maxed out setting means its disabled and 0 means it's not letting the TCC engage. Any thoughts?
Also on a side note separate from the TCC is the maf readings while driving. I'm using a LS7 card style maf and have a diverter screen in front of it. I've noticed up to 200-300 hz fluctuation of the maf while driving steady. I have read on other sites of people having similar issue's and having to put a second diverter screen after the maf too to keep turbulence down. Any thoughts on this too?"
Also like I mentioned in my last post, anyone have any ideas on this?
"Did some more checking and found my surging issue. I noticed when the car came to a stop and idled for a few minutes,the trans would engage something quick while sitting. (Felt like the car got pushed from the rear) Had a gut feeling it was the TCC so disabled any engagement completely and the surging disappeared.
Drives much better and rpms are steady now.
So I noticed in my tables a setting for max TCC limit torque was set to 0 stock. From what I can make sense of this 0 means no torque is allowed to TCC. When I compared to one of my other 4l80 files the setting was maxed out to 6042. I'm guessing the maxed out setting means its disabled and 0 means it's not letting the TCC engage. Any thoughts?
Also on a side note separate from the TCC is the maf readings while driving. I'm using a LS7 card style maf and have a diverter screen in front of it. I've noticed up to 200-300 hz fluctuation of the maf while driving steady. I have read on other sites of people having similar issue's and having to put a second diverter screen after the maf too to keep turbulence down. Any thoughts on this too?"