Subaru WRX G4X Idle when AC is On

[Ming]

I'm having issue with idle when the AC is turned on. Whenever I give it a quick rev idle will goes up then down below idle and bounce back to normal idle.

What do I need to check ? 

[Adamw]

attach the tune and a log.

[Ming]

17 hours ago, Adamw said:

attach the tune and a log.

Ok I will get back to you once I've done logging.

[Ming]

here's the log file 

 

[Adamw]

Try this, I have changed quite a few of the idle settings as it only had a very basic open loop config.  May need another log or two yet to get it dialed in.

SubaruV43378 new idle.pclx

[Ming]

On 6/14/2020 at 3:33 PM, Adamw said:

Try this, I have changed quite a few of the idle settings as it only had a very basic open loop config.  May need another log or two yet to get it dialed in.

SubaruV43378 new idle.pclx 368.06 kB · 0 downloads

hi adam i noticed its on closed loop now but the idle stay at 1.5k when i give it a quick rev. Also when the Ac is on the rpm goes up and down.

 

[Adamw]

Let me take another look tomorrow and will get back to you.  For some reason in that config I gave you idle ignition control isnt working and I cant see why.  I think I want to take a look with fresh eyes tomorrow.

[Ming]

3 minutes ago, Adamw said:

Let me take another look tomorrow and will get back to you.  For some reason in that config I gave you idle ignition control isnt working and I cant see why.  I think I want to take a look with fresh eyes tomorrow.

yeah sure adam. ill just use open loop for the time being. thanks

[Adamw]

Yeah, just load your original map back in.

[Adamw]

The idle ign not working correctly is due to a bug.  I will PM you a new version of PCLink and firmware with this fixed.  Please install it and update the firmware to V6.16.52 that is included in this install.  After that load in the "New Idle" map that I attached earlier.  

Do us another log, include some just general idling and a couple of throttle blips and the AC switching on.

[Ming]

1 hour ago, Adamw said:

The idle ign not working correctly is due to a bug.  I will PM you a new version of PCLink and firmware with this fixed.  Please install it and update the firmware to V6.16.52 that is included in this install.  After that load in the "New Idle" map that I attached earlier.  

Do us another log, include some just general idling and a couple of throttle blips and the AC switching on.

great will be downloading. many thanks

[Ming]

On 6/15/2020 at 6:22 AM, Adamw said:

The idle ign not working correctly is due to a bug.  I will PM you a new version of PCLink and firmware with this fixed.  Please install it and update the firmware to V6.16.52 that is included in this install.  After that load in the "New Idle" map that I attached earlier.  

Do us another log, include some just general idling and a couple of throttle blips and the AC switching on.

hi adam i've done afew logs. the idle is much better but when ever i do a quick rev it bogs down abit then up. 

 

[Adamw]

Did you mess with the dashpot offset setting when you were doing any of those logs?  In one log im trying to undersatnd why we didnt get the 7% dashpot in one place?

It looks not far off to me now.  You will need to experiment with the 3 dash pot settings to get rid of the undershoot after a blip.  I suspect you will need shorter hold and decay and possibly more offset but its but just to play with it live.

[Ming]

6 minutes ago, Adamw said:

Did you mess with the dashpot offset setting when you were doing any of those logs?  In one log im trying to undersatnd why we didnt get the 7% dashpot in one place?

It looks not far off to me now.  You will need to experiment with the 3 dash pot settings to get rid of the undershoot after a blip.  I suspect you will need shorter hold and decay and possibly more offset but its but just to play with it live.

Hi adam nope i didnt touch anything yet from the file setup that you previously sent. will try out the few things that you mention here.  which offset should i adjust?

many thanks adam

[Ming]

my idle has some cutout can you check here's my log

idle cut.llgx

[Adamw]

I dont see anything caused by the ecu, The engine was still running stable at 850RPM at the point it lost comms with PC Link.  This suggests power was lost.  

[Ming]

 

15 minutes ago, Adamw said:

I dont see anything caused by the ecu, The engine was still running stable at 850RPM at the point it lost comms with PC Link.  This suggests power was lost.  

i notice that if the idle ignition control was on it will cut off intermittently causing the car to have power lost.

[Adamw]

I dont see any evidence of that.  How reproducable is this?  How long does it idle for before it will stop?

Can you set up ecu logging like below, and next time it stops then download the ecu log and give us a look at that. 

Maybe add battery voltage to that logged list too.

[Ming]

On 6/15/2020 at 6:29 PM, Adamw said:

I dont see any evidence of that.  How reproducable is this?  How long does it idle for before it will stop?

Can you set up ecu logging like below, and next time it stops then download the ecu log and give us a look at that. 

Maybe add battery voltage to that logged list too.

here are my ecu log files and data logging

 

[Adamw]

Can you do a triggerscope at idle please.  Save it and attach the file here.

Can you explain the "cut out" in a bit more detail too.  Does the engine completely stop or is it just a short stumble and it recovers?  Does the laptop disconnect when it "cuts out"?

And are you saying with idle ignition turned off, it will idle forever, not cut out?  

[Ming]

24 minutes ago, Adamw said:

Can you do a triggerscope at idle please.  Save it and attach the file here.

Can you explain the "cut out" in a bit more detail too.  Does the engine completely stop or is it just a short stumble and it recovers?  Does the laptop disconnect when it "cuts out"?

And are you saying with idle ignition turned off, it will idle forever, not cut out?  

Hi how do you setup a triggerscope? 

The engine just stumble and recover and my laptop just freeze for few seconds everyone it stumble.

At first I tried to turn off idle ignition just to see if it still stumble down or not. But after awhile it's the same issue.

Now I've switched back to open loop it idles normally.

 

[Adamw]

Here's a video showing how to use the triggerscope with a G4+ ecu, you will find G4X is a little different but I think you will work it out with this:  https://1drv.ms/v/s!AiYbYlZQuRHPmidU5V2CmTcv6t2y?e=FIxeSC

 

34 minutes ago, Adison said:

At first I tried to turn off idle ignition just to see if it still stumble down or not. But after awhile it's the same issue.

Now I've switched back to open loop it idles normally.

So with idle speed control mode set to closed loop you get this stumble whether or not idle ignition control is on or not?

But with idle speed control mode set to open loop, you dont get this stumble?

[Ming]

On 6/16/2020 at 6:33 AM, Adamw said:

Here's a video showing how to use the triggerscope with a G4+ ecu, you will find G4X is a little different but I think you will work it out with this:  https://1drv.ms/v/s!AiYbYlZQuRHPmidU5V2CmTcv6t2y?e=FIxeSC

 

So with idle speed control mode set to closed loop you get this stumble whether or not idle ignition control is on or not? 

But with idle speed control mode set to open loop, you dont get this stumble?

1. Yes correct

2. Yes

there's no stumble on open loop.

 

[Adamw]

Ok, this is a tough one.  The stumble you have is caused by a trigger error, the ECU loses engine position for one revolution.  PC Link freezes while it does higher priority stuff when it sees the motor is still turning a split second later.  

But the problem is we cant see any obvious cause of the trigger error.  Your triggerscope looks good.  I can run your tune in an ecu on the bench with a simulated engine with closed loop idle enabled and it runs forever with no stumble. 

From your statements you only get this trigger error when closed loop idle is enabled but we cant find any reason in the software.  The feeling here at the moment is there is possibly something else involved like flyback voltage or inductive noise when the idle valve is working harder due to closed loop.  We dont have any engines in-house with a 3 wire idle valve to test.  One test that would be interesting if you are willing is to see if the engine will idle with the idle valve unplugged (might have to open the throttle a little to get enough air in), then turn on closed loop and see if it still stumbles with that potential noise source disconnected.

[Ming]

 

On 6/16/2020 at 4:05 PM, Adamw said:

Ok, this is a tough one.  The stumble you have is caused by a trigger error, the ECU loses engine position for one revolution.  PC Link freezes while it does higher priority stuff when it sees the motor is still turning a split second later.  

But the problem is we cant see any obvious cause of the trigger error.  Your triggerscope looks good.  I can run your tune in an ecu on the bench with a simulated engine with closed loop idle enabled and it runs forever with no stumble. 

From your statements you only get this trigger error when closed loop idle is enabled but we cant find any reason in the software.  The feeling here at the moment is there is possibly something else involved like flyback voltage or inductive noise when the idle valve is working harder due to closed loop.  We dont have any engines in-house with a 3 wire idle valve to test.  One test that would be interesting if you are willing is to see if the engine will idle with the idle valve unplugged (might have to open the throttle a little to get enough air in), then turn on closed loop and see if it still stumbles with that potential noise source disconnected.

Ok let me try disconnecting my Idle valve and see how its goes. Also i did try play around with the integral gain setting to 0.3 seems to be working better. But im not sure i still need to test it out.

I've attached my map and logged for you to check.