Help request for idle tuning

[afraptor22]

Having a rough time getting this combination to idle without keeping 5+ percent of APP to keep it running. This is my first experience with Gen 5 torque based tuning. I have been logging the torque spark and lowering the VTT table to reduce the amount of spark it's pulling. It seems to be getting better, I have to hold less APP, but I can't let my foot off or it dies. I have also be working on the VVE table at the same time with my wideband. I was hoping by working both at once I could at least get this to the point it will idle and I can drive it around to work on the VVE table under load. I have dual widebands installed about 6" behind the stock O2 sensors. Only the even bank is being logged though.

L86 stock long block
BTR 220 camshaft
Long Tube headers
L86 intake and throttle body
L86 MAF and MAP sensors
Manual transmission

The computer "identifies" as a 2014 Corvette so I could start with a manual transmission OS. I started with a stock L86 VTT set of data and the LT1 VVE table. I have attached the last two tune iterations and the logs that correspond to those tunes (5.2 and 5.3).

I have not touched the Driver Demand table. Just messed with some of the idle rpm and torque based tables based on other threads on this forum.

Thanks for any suggestions!

[GHuggins]

You basically have a cammed l86, so start with l86 tables and go from there. The rest of the background lt1 tables are really close so you'll be good there. Make sure you don't have any leaks anywhere and that includes holes in the tb. Just worked with one customer where his previous tuner drilled a hole in the tb because they didn't know what they were doing and no matter what I couldn't get the timing up. Replaced the tb and instantly 30+ timing at idle. Had to rework it and get if back down at that point.

You can do like Jason says to get idle timing up - make the maf 10% too rich and it will force the throttle to close then you can work things back from there. You really need the torque models balanced, however you'll have to do that after dialing in the MAF and VE. For now just get things close enough. The VVE tuning will help a lot, but you'll still have to tune in your torque model. After dialing in the torque model your fueling WILL BE different and will require readjusting. At that point the engine will start driving and running better.

Make sure you keep the same DD and torque management mapped gear settings as what's in the vette calibration.

[Alvin]

Your VVE table looks pretty rough.

Capture.PNG


I'd encourage you to purposefully fail the MAF and get the VVE dialed in pretty good before really messing with virtual torque.

[afraptor22]

Yes, half of the time when I calculate a new VVE table after changes it comes up with values in the 20,000 range for 2 areas and I end up having to redo it, but the picture you have is not what I see when I look at my VVE table, what gives? MAF is failed and shows the code in the scanner.

Im really just worried about the idle now since I can't easily drive the thing if it does every time I let off the accelerator pedal. I was hoping someone had advice about an idle table that I could modify to get it to stay running. In the idle area is 6-12% off so it's not a huge error.

Screenshot 2023-09-25 130920.jpg

Screenshot 2023-09-25 131248.jpg

[afraptor22]

You basically have a cammed l86, so start with l86 tables and go from there. The rest of the background lt1 tables are really close so you'll be good there. Make sure you don't have any leaks anywhere and that includes holes in the tb. Just worked with one customer where his previous tuner drilled a hole in the tb because they didn't know what they were doing and no matter what I couldn't get the timing up. Replaced the tb and instantly 30+ timing at idle. Had to rework it and get if back down at that point.

You can do like Jason says to get idle timing up - make the maf 10% too rich and it will force the throttle to close then you can work things back from there. You really need the torque models balanced, however you'll have to do that after dialing in the MAF and VE. For now just get things close enough. The VVE tuning will help a lot, but you'll still have to tune in your torque model. After dialing in the torque model your fueling WILL BE different and will require readjusting. At that point the engine will start driving and running better.

Make sure you keep the same DD and torque management mapped gear settings as what's in the vette calibration.

I have another L86 intake and throttle body so I'll swap them and see if it changes anything. By myself it's hard to track down leaks...maybe ill leave a brick on the pedal to keep it running so I can spray around the intake for leaks.

[GHuggins]

Alvin posted a pic from 5.3. It pulls up the same for me. Also pulls up a boosted vehicles VE table - possibly copied from the wrong base vehicle?

Change most of the tune over to the L86's and start over with your fuel tables then go from there.

[afraptor22]

Alvin posted a pic from 5.3. It pulls up the same for me. Also pulls up a boosted vehicles VE table - possibly copied from the wrong base vehicle?

Change most of the tune over to the L86's and start over with your fuel tables then go from there.

Weird, I had a company make a factory ECU for me with a corvette LT1 base tune. It matched a 2014 LT1 setup from the HP Tuners database, so I'm not sure why it looks like a boosted table. I'll copy over L86 VTT and VVE tables and go from there.

[Alvin]

The picture I posted was from the tune file you posted. Even if the idle areas ok.. when it returns to idle it will go though those spikes which will cause other issues.

[afraptor22]

I kept the base OS, because it's a manual and copied over most of the tables from the stock 2014 L86 that I found in the tune repository. The VVE table and scale is different now but I'd like someone else to look at it since it didn't display the weird spikes to be before, I probably don't see them now.

[GHuggins]

Weird, I had a company make a factory ECU for me with a corvette LT1 base tune. It matched a 2014 LT1 setup from the HP Tuners database, so I'm not sure why it looks like a boosted table. I'll copy over L86 VTT and VVE tables and go from there.

Well, guess I've never really paid attention as I plug my own premade tables into boosted setups, but it looks like most 5th gens are "somewhat" setup for boost from factory with obvious bad areas, but otherwise...

Here are some examples. I just have my editor set up to show higher than atmospheric right now because I've been working on boosted gen V's, so that's how these will appear.

This one is from yours

Current VE.jpg

This is a stock LT1

stock lt1 VE.jpg

This is a stock L86 just to give you an idea to the differences.

stock l86.jpg

I should also note that if your fueling is WAY off after starting with the right tables then you might want to try changing your injector flow rate setting to a different one. They had 3 different injectors flow wise that they ran in these. The L86's almost always had the bigger ones due to ethanol compatibility. The LT1's were hit and miss.

[afraptor22]

The picture I posted was from the tune file you posted. Even if the idle areas ok.. when it returns to idle it will go though those spikes which will cause other issues.

Thank you. Makes sense, but I wonder why I didn't see the spikes when I look at the VVE table. I have created a new file to try as GHuggins suggested and used 90% of the L86 tables.

[afraptor22]

Well, guess I've never really paid attention as I plug my own premade tables into boosted setups, but it looks like most 5th gens are "somewhat" setup for boost from factory with obvious bad areas, but otherwise...

Here are some examples. I just have my editor set up to show higher than atmospheric right now because I've been working on boosted gen V's, so that's how these will appear.

This one is from yours

Current VE.jpg

This is a stock LT1

stock lt1 VE.jpg

This is a stock L86 just to give you an idea to the differences.

stock l86.jpg

I should also note that if your fueling is WAY off after starting with the right tables then you might want to try changing your injector flow rate setting to a different one. They had 3 different injectors flow wise that they ran in these. The L86's almost always had the bigger ones due to ethanol compatibility. The LT1's were hit and miss.

Well it did idle on its own, but very poorly. Second iteration of VVE tuning it idled around 500rpm (930 commanded) at 92kpa. All iterations of VVE tuning after that it wouldn't idle on its own. Still pulling so much timing it's a bear to work with.

1986 C10 2014 LT1-L86 V1.2.hpt

C10 Idle LT1-L86 v1.2.hpl

Screenshot 2023-09-25 185826.jpg

[GHuggins]

You've actually got several issues going on in that log whether you're aware of it or not. First, it's firing up lean - most likely does this at all times and not just when it's cold from the looks of it. This on it's own is a combo of the density and open loop tables not to mention your torque tables not being dialed in. Idle timing's really negative and I do mean really negative and as you said is what's killing your motor. This is what's also causing your throttle to hang open more than it needs to be causing your engine load to go through the roof.

I addressed several issues in this one or at least hopefully got you something to get you close. It will hopefully allow you to dial in the VE and MAF. Make sure to do a throttle clean/reset after loading and firing. Don't know if it'll idle right or not as I didn't change any of your idle settings and those usually require calming down with cams. Either way you can load and try this one. Make sure to let if idle for awhile to let it recalibrate itself and for the timing to ease back up.

[afraptor22]

You've actually got several issues going on in that log whether you're aware of it or not. First, it's firing up lean - most likely does this at all times and not just when it's cold from the looks of it. This on it's own is a combo of the density and open loop tables not to mention your torque tables not being dialed in. Idle timing's really negative and I do mean really negative and as you said is what's killing your motor. This is what's also causing your throttle to hang open more than it needs to be causing your engine load to go through the roof.

I addressed several issues in this one or at least hopefully got you something to get you close. It will hopefully allow you to dial in the VE and MAF. Make sure to do a throttle clean/reset after loading and firing. Don't know if it'll idle right or not as I didn't change any of your idle settings and those usually require calming down with cams. Either way you can load and try this one. Make sure to let if idle for awhile to let it recalibrate itself and for the timing to ease back up.

Thank you, I'll try it tonight. I hadn't been letting it idle very long with the negative timing so I doubt it was able to "learn" any settings. Just so I understand the why, the changes to the O2 sensor settings do what, and which ones that you changed am I resetting after tuning to re-enable the closed loop? The injector changes are to help with the lean start up? The changes to the Open Loop fueling and the torque model make sense to me. Thanks.

[GHuggins]

Re-activated closed loop just because you're better off tuning with what the engine will be using. I put some general settings in for long tube headers.

Density changes is for the different airflow taking place through the motor. Most believe these are injector specific. If that was truly the case then why do different injectors in the same motor use the same density table from GM? Also why can you take the same injectors and put them into two slightly different motors from GM and they have different tables - has to be engine specific - right? That's how I approached it and found to hold true. I tune in the density table for engine changes.

Open loop is used for several seconds after engine fire. Seems to be used till after the initial O2 test take place, so lean or rich fueling during this time is "usually" VE, MAF, Open Loop and density associated. You address the open loop primarily after having the MAF, VE and density dialed in for all temps while prioritizing their dial in after the engine has run for several seconds and logged consistently the same each time.

Torque model should be close for now, but will require correcting after all of your fueling is dialed in.

Gen V's "learn" bad things. Can take up to 2hrs of drive time for them to settle out especially if they've been run on a bad tune long enough. Had a customer last week - idling constantly on -3ish to -10 and had been that way for months. I worked it and worked it. Couldn't get timing up. Told him to drive it and send me logs. Went from (-) to 3 to 8 and then the next log was nearly 40 at idle... At that point I had to counter shift everything. This is also why Alvin is saying to dial in the VE and see where it lands. There is an offset that takes place with changing the VE tables from stock that plays into the torque model, but I haven't had one completely go back to normal yet...

The one I posted may not even run, but it should...

[afraptor22]

Re-activated closed loop just because you're better off tuning with what the engine will be using. I put some general settings in for long tube headers.

Density changes is for the different airflow taking place through the motor. Most believe these are injector specific. If that was truly the case then why do different injectors in the same motor use the same density table from GM? Also why can you take the same injectors and put them into two slightly different motors from GM and they have different tables - has to be engine specific - right? That's how I approached it and found to hold true. I tune in the density table for engine changes.

Open loop is used for several seconds after engine fire. Seems to be used till after the initial O2 test take place, so lean or rich fueling during this time is "usually" VE, MAF, Open Loop and density associated. You address the open loop primarily after having the MAF, VE and density dialed in for all temps while prioritizing their dial in after the engine has run for several seconds and logged consistently the same each time.

Torque model should be close for now, but will require correcting after all of your fueling is dialed in.

Gen V's "learn" bad things. Can take up to 2hrs of drive time for them to settle out especially if they've been run on a bad tune long enough. Had a customer last week - idling constantly on -3ish to -10 and had been that way for months. I worked it and worked it. Couldn't get timing up. Told him to drive it and send me logs. Went from (-) to 3 to 8 and then the next log was nearly 40 at idle... At that point I had to counter shift everything. This is also why Alvin is saying to dial in the VE and see where it lands. There is an offset that takes place with changing the VE tables from stock that plays into the torque model, but I haven't had one completely go back to normal yet...

The one I posted may not even run, but it should...

It ran, after the second start it stayed running. Let it go for 4 minutes till the headers started to glow a bit to see if it would smooth out but it's still pulling timing. I took the wideband data and edited the VVE table and I'll see how that does before I mess with the VTT table, but I'm thinking it still may have to come down some. Very encouraging though. Here's the log and the VVE table I created for the next iteration. Feel free to comment if I'm on the right track with the changes. Do you think the idle airflow table needs to be reduced some to limit the high low roving?

[GHuggins]

Yes, once fueling corrections are made you'll most likely have to shift the torque model a little, but you will have to shift that VE a lot so it may pull it back in now.

If you have user defined parameters there is another background table that will get timing and torque both to come up on it's own at idle. You need to add some to idle airflow minimum - that's under cranking airflow - last column

Fueling is the same now from cold start to warm idle, so big improvement there.

Everything looks better. I do recommend using these attached channels - to use - download - right click - show in folder - right click - copy - open scanner - open recent channel config - open channel config - paste here and then click on. Should help you out to dial things in and then you can add whatever to them from there. These work on about every year model for the DI motors.

[afraptor22]

Well it's running and idling now. I got busy with work and this sat for a bit, but back at it. I am not getting any speed signal from the manual transmission. I thought I could pick up VSS signal from X2 pins 6 and 7, but after watching the Swap Time video it looks like I need a 3-wire and X2 pins 5, 8 and 21. I can drive the truck but with no speed data I don't think I'm going to get anywhere with the torque request table since it's always in the 0 VSS column. I ordered a 3-wire sensor for my TKX so I'll wire that in and see if I get speed and can start working on the drivability.