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Cam and TC in!, stalling issue when tuning.

5K views 29 replies 7 participants last post by  bluegoat06 
#1 ·
im having a problem tuning my car. it keeps stalling when i come off the throttle. idle is set to 1000 and runs fine otherwise. my trims arent that bad in the lower cells still but i cant log this thing without 2 foot driving and its annoying. any ideas what could cause this? any advice or comments appreciated on my newb tune.
 

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#2 ·
Does it just free fall to nothing? No resistance like it is trying to maintain or hold an idle?

Not 100% sure how the G8 is vs the LS F-body but if I had to guess your base idle running airflow table is probably off. Look up on HPT forums for the Russ K idle config. Start the car like you would in the morning and just have it log. Should calculate your desired vs current in the histogram and spit out the avg for what you need it to be for a good idle. IIRC with it being an auto you have to do it twice, once in park and another time in gear stopped.

After that you would have to deal with the throttle cracker and follower tables.
Those will help when there is a load on the car like turning and a higher demand on the ps pump or the ac being turned on.

Don't have my laptop in front of me atm so can't look at all the tables and tell you exactly which need tweaked. :(
 
#3 ·
i appreciate any help! i never knew such a tool existed. thanks much
it just free falls to stall, doesnt even try to run.
 
#4 ·
What are the specs of the cam ?
Can you describe the issue ?
Does the engine starts fine at first try ?
once started, it doesn't hold idle ?
I'll check a couple of things in the tune, and i'll wait for your responses.
 
#5 ·
Seems easy to fix :)
Your min RAF is stock, and because of the cam, some values would have go lower or higher in the idle rpm, lower more likely, also depending on your cam, you can adjust your idle rpm lower than 900rpm, (you bumped the master idle rpm to 1000rpm, but the idle speed min is 900rpm, thus the max the idle rpm would go is 900rpm), i'm sure your cam won't be that big, so you can have her idling at 750-800rpm and driving nicely.

I'll post something for you to do next. it's going to be fun :)
 
#6 ·
im gonna play with it today and use the russ k config.
the cam is 226/234 .598 .610 114+2
 
#7 · (Edited)
I don't know what Russ K config is
But you'll need to use Histo 10 and 11 from this config.

The cam has 2* overlap, should be a piece of cake to tune.

In your idle speed RPM, leave the 1000's up to 111F, from there on, lower than to 800 rpm. The min speed rpm should also match that, so set all the values in there to 800rpm.

Then Under engine/idle/airlfow/base running airflow/Airflow Final Minimum , zero out the entire Airflow Final Minimum table. (Min RAF). This prevents the PCM from predicting any minimum airflow which would prevent you from finding the real minimum. This is table as it looks stock. Zero all this out



Flash your calibration with this changes.

Then In your driveway or garage, start the motor and and warm her up,AC off, open your VCM Scanner. and start logging, although at this point you just want to see engine coolant temp.

Once the engine is warmed (close to normal operation temp, from 170F ECT and up is fine) in VCM controls, set spark idle control to "On" which really turns idle adaptive spark off.

Command the different RPM's in the table; 600, 800, 1000, 1200, You can only command up to 1200 RPM's in the VCM Controls with the up and down arrows. For 1600...3000 (you don’t need to go that high, doing this up to 1200rpm will suffice, but you’ll know if you need to go to 1600-3000rpm), you need to type the RPM in, and un-select and re-select "On".

Using histo# 10 and using the average (A) function, log airflow against the final idle airflow minimum table. (Histo 10 already does this). The idea is to command the lowest RPM in each range so you would find the minimum airflow needed for each rpm point to keep the motor running. remember to use the average funtion (A), if she stalls at 600rpm, don't worry, start with the 800rpm up to 1200rpm for now, then later repeat for 600rpm. keep each rpm point logging for about 15-20sec or so to get a good average. once done, stop the logging

Now Paste these numbers from Histo 10 table directly into the Airflow Final Minimum table (engine/idle/airlfow/base running airflow/Airflow Final Minimum (This is what we call Min RAF) (since we have Auto Trans, we need to do this twice, once in park, paste the values in the Park and Neutral row, and once in gear (Drive) w/ the e-brake on), Paste the values in the 1st gear row, then copy the 1st gear values to all the other gears but Park and neutral.
Once you've filled the values in, Then subtract 10% from the whole table (select all and multiply by .9) and re-flash.
Also don't worry about the fields above 1200rpm, you can leave them at 0. you're doing this from 600 to 1200rpm.

Restart the engine, this time do not set the idle spark control to "on". Log idle adapt advance against the final idle airflow minimum table with histo# 11 using the average (A). Command the RPM's again, just like before. Copy and paste these numbers (paste special, multiply by %) into the appropriate cells. (again, we auto guys will need to do this twice) Rinse, repeat until the adaptive spark numbers are +-1 degree.

Piece of cake, just time consuming, but she should behave a lot better after this :)

Let me know if you have any questions.
 

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#13 ·
I don't know what Russ K config is
But you'll need to use Histo 10 and 11 from this config.

The cam has 2* overlap, should be a piece of cake to tune.

In your idle speed RPM, leave the 1000's up to 111F, from there on, lower than to 800 rpm. The min speed rpm should also match that, so set all the values in there to 800rpm.

Then Under engine/idle/airlfow/base running airflow/Airflow Final Minimum , zero out the entire Airflow Final Minimum table. (Min RAF). This prevents the PCM from predicting any minimum airflow which would prevent you from finding the real minimum. This is table as it looks stock. Zero all this out



Flash your calibration with this changes.

Then In your driveway or garage, start the motor and and warm her up,AC off, open your VCM Scanner. and start logging, although at this point you just want to see engine coolant temp.

Once the engine is warmed (close to normal operation temp, from 170F ECT and up is fine) in VCM controls, set spark idle control to "On" which really turns idle adaptive spark off.

Command the different RPM's in the table; 600, 800, 1000, 1200, You can only command up to 1200 RPM's in the VCM Controls with the up and down arrows. For 1600...3000 (you don’t need to go that high, doing this up to 1200rpm will suffice, but you’ll know if you need to go to 1600-3000rpm), you need to type the RPM in, and un-select and re-select "On".

Using histo# 10 and using the average (A) function, log airflow against the final idle airflow minimum table. (Histo 10 already does this). The idea is to command the lowest RPM in each range so you would find the minimum airflow needed for each rpm point to keep the motor running. remember to use the average funtion (A), if she stalls at 600rpm, don't worry, start with the 800rpm up to 1200rpm for now, then later repeat for 600rpm. keep each rpm point logging for about 15-20sec or so to get a good average. once done, stop the logging

Now Paste these numbers from Histo 10 table directly into the Airflow Final Minimum table (engine/idle/airlfow/base running airflow/Airflow Final Minimum (This is what we call Min RAF) (since we have Auto Trans, we need to do this twice, once in park, paste the values in the Park and Neutral row, and once in gear (Drive) w/ the e-brake on), Paste the values in the 1st gear row, then copy the 1st gear values to all the other gears but Park and neutral.
Once you've filled the values in, Then subtract 10% from the whole table (select all and multiply by .9) and re-flash.
Also don't worry about the fields above 1200rpm, you can leave them at 0. you're doing this from 600 to 1200rpm.

Restart the engine, this time do not set the idle spark control to "on". Log idle adapt advance against the final idle airflow minimum table with histo# 11 using the average (A). Command the RPM's again, just like before. Copy and paste these numbers (paste special, multiply by %) into the appropriate cells. (again, we auto guys will need to do this twice) Rinse, repeat until the adaptive spark numbers are +-1 degree.

Piece of cake, just time consuming, but she should behave a lot better after this :)

Let me know if you have any questions.
this is awesome. im learning alot. now my only problem is the break points are in your config are different than the breakpoints in the editor. how do i change these to be the same?
 
#8 ·
hmm, it says #11 is unsupported, why would this be?
 
#9 ·
Check the config setup for the histo, a pid needed is probably missing from the main table. you need to be logging idle adapt advance for histo 11
 
#10 ·
ok, im reading 15 g/sec at running ect's on my log and my tune raf in my tune is at stock, should i change my raf to be 15 at 800 rpm and scale the rest of the raf accordingly?
 
#11 ·
just went for a drive and it didnt stall once... good start. im gonna keep working on these tables. what would cause surging? the stall is a 2800 triple disc PI
 
#12 · (Edited)
The Min RAF is your main idle source, you won’t get a stable idle with a cam and a stock table, or a table that has been screwed up with random values. This table lets the PCM know how much air is entering the engine, the airflow is directly affected by the cam overlap, you’re bringing more air with the cam, and should be adjusted accordingly. Smaller cam with large lsa’s would require less air than larger cams with narrower lsa’s. This is one of those items where remote tunes fail miserably, to much airflow in the Min RAF and the rpm will hang, too little, and the rpm would surge, then the tuner would tell you "It is just the nature of the cam" IF they know about the Min RAF, some tuners play with the wrong tables or don't even know what they do, and when is remote tuning, well, i won't even go there.... , but even your local dyno tooner can do the same, so it really comes to, "should i trust", or "let me see if i can trust", it takes some times, but as you'll learn, tuning is not complicated, and it let you understand for yourself :)

Have fun.
 
#14 ·
break points ?
 
#15 ·
I think i know what you're talking about, try this config, same name, but i modified Histo 9 10 and 11 so the rpm in the x axis, match what we have in the G8 calibration. i use the same procedure for LS2 GTO's and Ls2/Ls3 Vettes, so the x axis are different :)
 

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#16 ·
Been busy with the newborn. im back to getting this POS running properly. where is the idle adapt advance against the final idle airflow minimum table?
 
#17 ·
Congrats on the newborn, i know the fun starts during their first 4 months, wife is so tired, dad has to feed and clean poo every 2 hours during the entire night :) i have 3 little ones, but they're now 6 5 and 3.

That table is actually a custom histogram, basically, when you're done with the first portion of the idle-airflow procedure where you're trying to find the min airflow to build your Min-RAF table (remember you zeroed out the min-raf, to start finding what the engine actually wants), then you'll use Hist#11 to add or substract airflow from the min-raf table, based on the logs youre getting from Histo#11, Histo11 at this point doesn't use Spark control, like you did when you were logging the needed data for histo 10.

Have fun.
 
#18 ·
i see, that makes sense. and once i get the min raf done, how do i optimize my timing for idle?
 
#19 ·
You can leave the idle timing along, lots of the stuff people did back in the days of the LS1 or most recently with LS2 and radical cams are not needed with our engines because L92 heads doesn't seem to like a lot of reversion, and cam overlap is minimal, so idle tuning is a piece of cake. your cam only have 2* overlap, there is only minimal things to adjust for a stable idle, now try the same with a cam that gives 16* overlap, and things are different, but the min-raf concept is still the same.
 
#20 · (Edited by Moderator)
bluegoat i sent you a pm, also i cant get a higher commanded rpm than 1200, there seems to be no way i can enter any numbers in the field.
 
#22 ·
Yep, that's normal, it behaves the same in the E40 PCM :)
What you can do do, is set the idle rpm manually typing the rpm value you want in the rpm field (1600 in this case), and then click RPM on, however, you won't need to do this procedure past 1200rpm because your cam won't requiere it. You can leave the tables populated up to 1200, the rest can be all zeros if you wanted, or you can paste the stock values past 1200rpm, and do little interpolation in the 1600 rpm field. You'll have to the interpolation for the 400 and 200 rpm since it'd would impossible to keep the engine idling that low for test purposes, i normally keep the 200-400rpm at about 0.5 to 1g/sec lower than what i have in the 600rpm field. but you can play with this after you have completed the procedure, not a problem
 
#21 ·
If you have a triple-disk converter, you will most likely have to command 0 rpm in all the TCC slip tables or it will surge at a cruise.
 
#24 ·
My car has been stalling occasionally since the mild cam install. So I searched and came up with this informative thread. Thanks again BlueGoat! However, I encountered two issues:
1.) The VCM controls only work with the car in park. Maybe a feature of a newer version of HPT?

2.) I don't quite understand what the destination table is here. It seems like you are talking degrees but later in the thread said to not mess with the advance tables....
Restart the engine, this time do not set the idle spark control to "on". Log idle adapt advance against the final idle airflow minimum table with histo# 11 using the average (A). Command the RPM's again, just like before. Copy and paste these numbers (paste special, multiply by %) into the appropriate cells. (again, we auto guys will need to do this twice) Rinse, repeat until the adaptive spark numbers are +-1 degree.
 
#25 ·
Do the work in Park or Neutral, then use the same values for drive and the other gears.

The adaptive spark numbers come from Histo#11, it's kind of adaptive spark error% against airflow, apply to the Min RAF until the error is +-1 %.
 
#27 ·
I have a new config i posted here somewhere cause i didn't realize i was posting a config from a GTO.

Let me find it.
 
#28 ·
#30 ·
Np.
 
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