About to throw in the towel nailing down idle

[kj217]

It doesn't contain what I need. Here is another config that uses MAF instead of dynamic airflow. You should be able to run through the procedure with it, at least histo 10 will work, I don't see why 11 wouldn't.

how to edit rpm scaling in the scan config file?

[kj217]

the two histograms are not supported in latest vcm scanner,, car is 09 ctsv,,
any newer versions of this config available?

[5_Liter_Eater]

No plans for it no.

[2004gtols1]

Tried using this config without the maf since the car is sd tuned. The airflow histo created numbers from 9-12 or maybe even 13 and it wint even copy paste special into the airflow minimum table.

Wonder what I'm doing wrong or need to change?

I have a log on my computer I'll post when I'm home from work.

[daniel76309]

Thanks to Bill for submitting this technique.

I am hoping that someone can suggest what I am missing here...

No matter what I do, I cannot get it to idle below ~875 RPM, which is the original factory setting.

Right now the target idle speed and minimal idle speed are both 800, but if I set them at 600 it wouldn't make any difference--it would still idle at ~875.

I have zeroed the airflow final minimum table as specified and idle spark is set to 20 degrees.

With VCM controls I can command a HIGHER idle speed, i.e. if I set it at 1200 it will go to 1200, but going lower has no effect below ~875. I would like to be able to go to a lower idle speed in order to use this technique for dialing in the idle, but as it is I cannot.

It is an LS376-480 engine with GMPP controller package (E67).

Suggestions?

[5_Liter_Eater]

The histo is plotting in g/sec. Check the units in the editor for the table in question and make sure they match.

Tried using this config without the maf since the car is sd tuned. The airflow histo created numbers from 9-12 or maybe even 13 and it wint even copy paste special into the airflow minimum table.

Wonder what I'm doing wrong or need to change?

I have a log on my computer I'll post when I'm home from work.

[5_Liter_Eater]

Post a log of this behavior with the config from this thread.

Thanks to Bill for submitting this technique.

I am hoping that someone can suggest what I am missing here...

No matter what I do, I cannot get it to idle below ~875 RPM, which is the original factory setting.

Right now the target idle speed and minimal idle speed are both 800, but if I set them at 600 it wouldn't make any difference--it would still idle at ~875.

I have zeroed the airflow final minimum table as specified and idle spark is set to 20 degrees.

With VCM controls I can command a HIGHER idle speed, i.e. if I set it at 1200 it will go to 1200, but going lower has no effect below ~875. I would like to be able to go to a lower idle speed in order to use this technique for dialing in the idle, but as it is I cannot.

It is an LS376-480 engine with GMPP controller package (E67).

Suggestions?

[DrkPhx]

Does HPT have access to Max Idle Area 1 and 2? Reducing these values will allow the E38 and E67 ECM's will control idle speed rpms.

[daniel76309]

Post a log of this behavior with the config from this thread.

Well, that brings me to something else, I was trying not to ask too many questions at once...

I was not able to open the config file from this thread, and I am thinking it may be because I have a newer version of HPT.

I did set up my own config which may not be quite "it", perhaps you could let me know. I used histogram #3 in my config to plot "dynamic air" v. RPM on one axis, and MAF hz on the other axis. Then I tried making a log with the engine idling, and tried controlling engine speed with VCM controller. The histogram shows about 1.4 lb/min at 800 RPM increasing to about 1.9 lb/min at 1200 RPM. So I may have overstated the 875, it apparently does vary down to 800 (enough to get data anyway), but that is as low as it would go.

Thoughts? Am I on the right track, and any ideas why it won't idle down any slower?

Thanks!

[5_Liter_Eater]

When you guys say you're not able to open the config in 2.24 do you mean when you connect it to the car and try to start scanning? Because I'm able to open it with 2.24.x and I was able to take a log from earrlier in this thread and open it and histos 10 and 11 work.

[daniel76309]

I wasn't connected to the car when I tried opening it. (I will try that though and see if it makes a difference--will let you know.)

I get an error pop up that says "unable to parse log", and "2461 of 2466 bytes read".

OK, I tried it when connected to the car, I get the same thing. I tried it in different combinations, all plugged into the interface, but with ignition off, ignition on, not connected to scanner, and connected to scanner, and no go with any of them. Apparently something is not compatible.

Thanks!

[MikeOD]

Does HPT have access to Max Idle Area 1 and 2? Reducing these values will allow the E38 and E67 ECM's will control idle speed rpms.

What do you mean?

[DrkPhx]

What do you mean?

Sorry. I included some info below. I don't know if this will help or not, but it's worth a try imo.

No matter what I do, I cannot get it to idle below ~875 RPM, which is the original factory setting.

Max Idle Area 1 - Maximum throttle effective area that can be commanded during idle control.
In this particular case, lowering the value would drop the max area "ceiling" allowing for a lower idle rpm.

Max Idle Area 2 - Maximum throttle effective area that can be commanded during idle control, this is used to prevent the vehicle creeping forward with the brake pressed.
Same as above for auto cars.

[daniel76309]

Thank you. If I can find that I will give that a try!

[MikeOD]

Thank you. If I can find that I will give that a try!

Engine - Idle - Airflow - (on the right under Effective Area), you're looking at "Percent Max" and "Percent Max - Brake"

[5_Liter_Eater]

I'm able to open it with 2.24.322.

I wasn't connected to the car when I tried opening it. (I will try that though and see if it makes a difference--will let you know.)

I get an error pop up that says "unable to parse log", and "2461 of 2466 bytes read".

OK, I tried it when connected to the car, I get the same thing. I tried it in different combinations, all plugged into the interface, but with ignition off, ignition on, not connected to scanner, and connected to scanner, and no go with any of them. Apparently something is not compatible.

Thanks!

[daniel76309]

I'm able to open it with 2.24.322.

OK, thanks. I had to check--I have version 2.24.57 (purchased a little over a year ago).

[daniel76309]

Engine - Idle - Airflow - (on the right under Effective Area), you're looking at "Percent Max" and "Percent Max - Brake"

Thanks. I tried changing the value from (8149?) to 4000 and no effect, so went all the way to 200 and still no effect.

These things don't always seem to make sense to me, but I would THINK that I would be looking for a min value of something, rather than a max. Still, it was worth trying and I appreciate the suggestion.

[DrkPhx]

Thanks. I tried changing the value from (8149?) to 4000 and no effect, so went all the way to 200 and still no effect.

These things don't always seem to make sense to me, but I would THINK that I would be looking for a min value of something, rather than a max. Still, it was worth trying and I appreciate the suggestion.

Sounds like you changed Airflow Area Conversion Max and Min. I was referring to Max Idle Area which typically has a default value of 2.46 %. Reducing it to 1.46 will usually help.

[daniel76309]

OK, thanks, you are correct. I found the values you are referring to now...on mine they are both 2.51%. I will give that a try also.