Gen4 idle tuning guide

[Michael_D]

Which version of the tune? With your test settings?

Don't know if you're interested, but I built a spreadsheet that uses OEM min air multipliers. I didn't know what to set all the other min air flow tables to, after dialing in the 650 - 1200 rpm, neutral cells. It basically just uses the multiplier in the OEM table to populate the rest of the table.

Probably would have helped to post my layout too...

IDLE AIR.xlsx

6-11-16_idle cal tune-03.hpt

Idle cal layout.Layout.xml

[BigMike42]

Which version of the tune? With your test settings?

Don't know if you're interested, but I built a spreadsheet that uses OEM min air multipliers. I didn't know what to set all the other min air flow tables to, after dialing in the 650 - 1200 rpm, neutral cells. It basically just uses the multiplier in the OEM table to populate the rest of the table.

Probably would have helped to post my layout too...

IDLE AIR.xlsx

6-11-16_idle cal tune-03.hpt

Idle cal layout.Layout.xml

Cool tool, I never know what to set them to either, i just arbitrarily go up .5-1g at a time. Seems to work fine. I will give your spread sheet a shot.

[GHuggins]

Beware running too low of idle airflow. It will completely kill reserve torque. You don't want to do that.

Don't want to sidetrack this which is why I haven't posted anything about this - really liking this thread by the way - thank you for all your hard work on this - but you might want to hear Dave out... I typically will lower or leave idle spark the same as factory... If you raise it too much and adversely lower idle air too much, it will make things like heavy loads kicking in kill the motor - I've seen something as simple as hitting the bump stops on the steering kill an engine with too high of idle timing... I try to tune them to where I can "with automatics" pull the shifter into drive from a neutral position with the brake applied while simultaneously hitting the bump stop on the steering with the AC on - this "best" assures most torque reserve possible with idle...

This is why for timing "I" try to "power tune" the idle - lower main base idle timing to something from 10 to 22 degrees - yes this will make it more lopey, put main idle timing areas in the main spark tables in the low to mid 40's "this raises the roof so to speak on the spark reserve ability" then increase the over and under speed spark corrections to where the bigger error areas peak around 22 degrees - you can leave the smaller errors low if you wish for main idle reasons... Then you if need be you can play with throttle settings that effect all idle airflow tables at once so the throttle will react better to changing loads and not over react to loss of loads...

I personally have spent over a full day tuning just the idle messing with all of the tables your listing - just never really had an "exact" science to it like this - again thank you and I will be trying this out as you've described I don't like doing the throttle brakes like how it's said to do on EFI's write-up - always seems to put the settings WAY too low - instead I set min air to what I'm seeing in the MAF g/s during a hot idle, leave proportional and integral airflow all where it's at then raise or lower the brake settings to where when I use the bi-directional controls in the scanner, I can only force the idle rpm 100 less than what I'm commanding in the tune... Doing it the other way I wind up with unnecessarily induced hot or cold starting problems and loosing some of the idle torque reserve...

Just some thoughts... Again thanks for your hard work...

[GHuggins]

Which version of the tune? With your test settings?

Don't know if you're interested, but I built a spreadsheet that uses OEM min air multipliers. I didn't know what to set all the other min air flow tables to, after dialing in the 650 - 1200 rpm, neutral cells. It basically just uses the multiplier in the OEM table to populate the rest of the table.

Probably would have helped to post my layout too...

IDLE AIR.xlsx

6-11-16_idle cal tune-03.hpt

Idle cal layout.Layout.xml

This is another good point - not sure if anyone else has noticed or not, but it seems like you can only gain anything from raising the min air up to a point - usually right around 12 g/s...

If I'm possibly getting anywhere near this there are a couple of things to correct it - first you can raise the %brakes - another reason why I tune these the way I do...

Or simply raise the ect multiplier small amounts at a time "more or less the way the OE does it", until you get your min air table back below 10's...

Going to have to look into your spreadsheets too Michael Is there a guide for dummies on how to best utilize or use this? OR do we just post the Values straight out of the tune and it alters the table to show the "actual" min air??? Thank You...

[BigMike42]

Don't want to sidetrack this which is why I haven't posted anything about this - really liking this thread by the way - thank you for all your hard work on this - but you might want to hear Dave out... I typically will lower or leave idle spark the same as factory... If you raise it too much and adversely lower idle air too much, it will make things like heavy loads kicking in kill the motor - I've seen something as simple as hitting the bump stops on the steering kill an engine with too high of idle timing... I try to tune them to where I can "with automatics" pull the shifter into drive from a neutral position with the brake applied while simultaneously hitting the bump stop on the steering with the AC on - this "best" assures most torque reserve possible with idle...

This is why for timing "I" try to "power tune" the idle - lower main base idle timing to something from 10 to 22 degrees - yes this will make it more lopey, put main idle timing areas in the main spark tables in the low to mid 40's "this raises the roof so to speak on the spark reserve ability" then increase the over and under speed spark corrections to where the bigger error areas peak around 22 degrees - you can leave the smaller errors low if you wish for main idle reasons... Then you if need be you can play with throttle settings that effect all idle airflow tables at once so the throttle will react better to changing loads and not over react to loss of loads...

I personally have spent over a full day tuning just the idle messing with all of the tables your listing - just never really had an "exact" science to it like this - again thank you and I will be trying this out as you've described I don't like doing the throttle brakes like how it's said to do on EFI's write-up - always seems to put the settings WAY too low - instead I set min air to what I'm seeing in the MAF g/s during a hot idle, leave proportional and integral airflow all where it's at then raise or lower the brake settings to where when I use the bi-directional controls in the scanner, I can only force the idle rpm 100 less than what I'm commanding in the tune... Doing it the other way I wind up with unnecessarily induced hot or cold starting problems and loosing some of the idle torque reserve...

Just some thoughts... Again thanks for your hard work...

Yep, this is why I didn't go into too much detail on optimal spark or rpm. I just wanted to talk mostly about how to isolate the base airflow table and setup a strategy in order to find the optimal settings.

I have personally tried spark between 10 and 22 degrees on my own car. 10 had the best driveability (good downshift and coast behavior) but I couldn't stand the car shake with my baby in the back seat, so I settled on 20.

I did exactly what you did before with the maf airflow mapping it to grams. I also did the one way by leaving the max idle area low, so the trimming could only be within about .8% tps or so. But like you said, cold starts don't work. I loved that Efi live thread, but didn't like the idea of drilling the TB to help cold starts, so I wanted to find a different way. Maybe with others trying it in this thread, we can refine the process even more.

I have probably flashed over 1000 tunes trying to figure all this stuff out. Does 3.0 flash a lot faster than 2.24? I may have to get on that if so to save time lol.

[DSteck]

3.0 flashes slower because apparently it actually follows the rules of speed on the CAN bus whereas 2.24 didn't.

[BigMike42]

3.0 flashes slower because apparently it actually follows the rules of speed on the CAN bus whereas 2.24 didn't.

But it can flash just the engine side, so maybe I'll save time there. I forgot I did use the beta for a while, I assume it's the same speed as that? If so, it's pretty slow...

[Michael_D]

When you say "above 10 gs", where on the table? My car won't run at all under 10, even at idle. I'm around 11 now, and it seems happy. Maybe I have something mechanical going on??

Well back with 2.24, all I could command with the scanner controls was 650 - 1200. I was using the 'adaptive idle spark' method to cal min air, and I just raised idle spark 4 deg over stock, based on some input I got from Dan Maslic. So....after getting the neutral row, 650-1200 happy, that's all I could do. Some people say to just carry that value out to the end of the row, but that just doesn't seem right to me. The engineers who figured this table out didn't do that.... So, I just built the spreadsheet to look at the 1200 rpm cell value and populate the rest of that row with the multiplied value in the OEM calibration off of the 1200 rpm cell. Then I just use the same multiplier from the neutral row to the remaining rows.

Once you get the neutral min air set between 650 and 1200, drop those values into the spreadsheet and it should populate the rest of the table. This is all off my 08 Z06 of course. Hardly scientific, but the best idea I could come up with at the time....

Time for dinner and a cocktail... I have an ECM to swap out tomorrow. Thanks Dave!

[BigMike42]

When you say "above 10 gs", where on the table? My car won't run at all under 10, even at idle. I'm around 11 now, and it seems happy. Maybe I have something mechanical going on??

Well back with 2.24, all I could command with the scanner controls was 650 - 1200. I was using the 'adaptive idle spark' method to cal min air, and I just raised idle spark 4 deg over stock, based on some input I got from Dan Maslic. So....after getting the neutral row, 650-1200 happy, that's all I could do. Some people say to just carry that value out to the end of the row, but that just doesn't seem right to me. The engineers who figured this table out didn't do that.... So, I just built the spreadsheet to look at the 1200 rpm cell value and populate the rest of that row with the multiplied value in the OEM calibration off of the 1200 rpm cell. Then I just use the same multiplier from the neutral row to the remaining rows.

Once you get the neutral min air set between 650 and 1200, drop those values into the spreadsheet and it should populate the rest of the table. This is all off my 08 Z06 of course. Hardly scientific, but the best idea I could come up with at the time....

Time for dinner and a cocktail... I have an ECM to swap out tomorrow. Thanks Dave!

I think he was referring to the max idle % that I referenced a few posts back. Meaning, in stock tunes you see large numbers like 25 g/s, but these actually don't do anything because they were well past the max allowed TPS % anyway.

[schpenxel]

But it can flash just the engine side, so maybe I'll save time there. I forgot I did use the beta for a while, I assume it's the same speed as that? If so, it's pretty slow...

Yeah, not having to flash transmission is nice. Should be same speed as 2.25

Though when you DO flash both computers in one go there's a pretty long pause between ECM flash and TCM flash which I don't love, but not that big a deal either.

[BigMike42]

Yeah, not having to flash transmission is nice. Should be same speed as 2.25

Though when you DO flash both computers in one go there's a pretty long pause between ECM flash and TCM flash which I don't love, but not that big a deal either.

Yeah not a huge deal, but adds up when you're flashing every 5 mins or so lol.

I was tuning my Dad's '02 z the other day and the ecm flashed in roughly 8 seconds. I want that!

[BigMike42]

Played with my 2-1 today a bit. I raised 2-1 shift mph to 8.6mph and set my idle MPH to 8.3 and delay to 900 msec. It's pretty much good, maybe could make the coast down integral slightly more aggressive so it doesn't hover above target idle, but I don't even feel the shift now so I don't really care. Note the spark on all the shifts, stuck at 8 degrees so no flares.

stop 2-1.png

stop.hpl

gen4idle.cfg

[akruzz]

**Step 1 continued**

Find your best idle

1. With the car fully warmed up, start her up.
2. Gently depress the throttle so the RPMS go up a bit, to say 1500 or so. This is going to knock you out of idle correction and bump you into the main spark tables. You have 409 seconds before adaptive idle comes back after every blip.
3. Let the idle stabilize, you may have to have some finesse with the pedal to keep her running. If it's wanting to die on you right off the bat, increase idle airflow.


What if I followed exactly whats been outlined, but when I get to step #3, I can't get it to idle by increasing airflow? I started at 9 and went all the way to 16. How much is too much? I have to keep my foot touching the pedal to keep it running. I've also tried raising all of my idle setting up to 1000. Still wants to die unless I keep a tad bit of pedal pressure. It runs good above 1300 rpms.

Three days of trouble shooting this idle problem.
Started with a 2008 LY6 6.0L
Added the following:
PSI harness, ECU and corvette pedal
VVT delete package from summit
EPS cam (not crazy big, a 7 on scale of 1-10, I can list the spec if it would help)
LS3 intake with stock injectors

[BigMike42]

**Step 1 continued**

Find your best idle

1. With the car fully warmed up, start her up.
2. Gently depress the throttle so the RPMS go up a bit, to say 1500 or so. This is going to knock you out of idle correction and bump you into the main spark tables. You have 409 seconds before adaptive idle comes back after every blip.
3. Let the idle stabilize, you may have to have some finesse with the pedal to keep her running. If it's wanting to die on you right off the bat, increase idle airflow.


What if I followed exactly whats been outlined, but when I get to step #3, I can't get it to idle by increasing airflow? I started at 9 and went all the way to 16. How much is too much? I have to keep my foot touching the pedal to keep it running. I've also tried raising all of my idle setting up to 1000. Still wants to die unless I keep a tad bit of pedal pressure. It runs good above 1300 rpms.

Three days of trouble shooting this idle problem.
Started with a 2008 LY6 6.0L
Added the following:
PSI harness, ECU and corvette pedal
VVT delete package from summit
EPS cam (not crazy big, a 7 on scale of 1-10, I can list the spec if it would help)
LS3 intake with stock injectors

I'll take a look later, can't see tunes at work. I never tried it with a car that had it's ECU guts and pedal swapped over. Does the car idle with the adaptives on? Do you see the TPS% going up when you add base airflow?

Cam specs would help.

[BigMike42]

I'll take a look later, can't see tunes at work. I never tried it with a car that had it's ECU guts and pedal swapped over. Does the car idle with the adaptives on? Do you see the TPS% going up when you add base airflow?

Cam specs would help.

Also, check the posts and look at the max idle area method, it's a bit easier to use. Actually, come to think of that, make sure you have high values populated for that. It could be set too low and changes to base airflow will not reflect.

[GHuggins]

Mike would have seen it if he were able to look at your tune, but believe your ect multiplier is your problem... Here's a 6l ect multiplier table and a min air table that should be close to what you need...

Hope this helps you out.

[BigMike42]

Got a chance to play with the idle guide steps a bit at lunch. There IS one more step I have to add. With my smaller cam, it didn't come into play, but with your guys bigger cams it's going to skew the results.

Since we are kicking it out of idle mode, the throttle follower airflow correction is going to come into play. These tables also have to be zero'd out. Now, you may just be able to get away with zeroing out the airflow->torque follower->max airflow table, but I am not 100% sure, so I just zero'd out every table on both the idle->rpm->follower side and idle->airflow->torque follower side.

Now TPS does not budge. With my smaller cam, it was fluttering ever so slightly, but I thought it was just a glitch in the PCM, but it was actually the very slight correction from the follower tables.

I will update the guide when I get home

[akruzz]

Wow! Thanks GHuggins and BigMike42 for leading me to my the fix. My multipliers were the issue. Now I've got it to idle. I spent hours searching this forum and trying several things before I asked for help. And then BAM, you guys helped me chase the problem out. Now back to Step 1 to get it dialed in. Thanks again.

[BigMike42]

Wow! Thanks GHuggins and BigMike42 for leading me to my the fix. My multipliers were the issue. Now I've got it to idle. I spent hours searching this forum and trying several things before I asked for help. And then BAM, you guys helped me chase the problem out. Now back to Step 1 to get it dialed in. Thanks again.

Awesome, thanks GHugg's for the assist.

Don't forget the step I just added a few moments ago . Gotta zero out the followers too. Then it will be easy to dial in and find dead nuts base airflow.

[GHuggins]

Wow! Thanks GHuggins and BigMike42 for leading me to my the fix. My multipliers were the issue. Now I've got it to idle. I spent hours searching this forum and trying several things before I asked for help. And then BAM, you guys helped me chase the problem out. Now back to Step 1 to get it dialed in. Thanks again.

You can also use this table by increasing or decreasing it to get your min air idle area below that 12g/s target area too... I look at the min air table as a window and the multipliers roughly moving the target to that window if that makes sense You'll have to do this on some of the really large TB's because they move right out of that factory designed window - no matter how much you play with the brake or min air settings they'll never idle right

Awesome, thanks GHugg's for the assist.

Don't forget the step I just added a few moments ago . Gotta zero out the followers too. Then it will be easy to dial in and find dead nuts base airflow.

Now Mike, when you say to (0) these out, your referring to "all" the rpm follower tables and just the air max torque follower table - correct? I assume you don't leave them like this when your done either - right?
Thanks