Tuning idle

I'm wanting to start things off by tuning idle. Where is issue lies is the engine wants to die when I let off throttle, but I can give it a little throttle and it is fine. The car idles fine otherwise. This only happens when it is warmer out.

Where do I edit these in ATR? I see the Idle Control Tables, but there are 10 of them.. where do I begin?

Using stock Cobb stage 2 OTS 91 octane map.

05 STi
fully build block
JE Pistons
Manley H beam connecting rods with rings
Clevite main and rod bearings
ARP headstuds

TGV Delete

Stage 1 Exedy clutch

Cobb TBE

Stock airbox K&N filter
Stock turbo
Stock injectors
Stock fuel pump
 

IGOTASTi

System Operator
Staff member
[MENTION=9]HolyCrapItsFast[/MENTION] [MENTION=4577]TK-421[/MENTION]
 

TK-421

New member
Sounds like you might have a vac leak to be honest.

Before going into ATR and doing adjustments, you should rule out mechanical issues first.

Idle isn't really something we adjust, the only time I usually adjust idle is when there is a aggressive camshaft profile that's being used.

You really need to do a vac leak check and a boost leak test.
 
rebuilt motor and new lines.. It only does this when it is hot outside or after I reset the ecu. It learns itself out of it, but there has to be a way to fix it.
I figured it was doing this because of the TGV Delete and forged internal weight difference..?? It also got a 3 angle valve job as well if that makes a difference.
 

TK-421

New member
rebuilt motor and new lines.. It only does this when it is hot outside or after I reset the ecu. It learns itself out of it, but there has to be a way to fix it.
I figured it was doing this because of the TGV Delete and forged internal weight difference..??

TGV deletes and the weight of internals are not going to make a difference.

It honestly seems like a gasket or vac leak somewhere in the system.

This just isn't a sole tuning issue, just check the mechanical stuff out first before going into ATR and changing settings.

Out of curiosity who did the engine build?
 

HolyCrapItsFast

Drinks beer!
I see this all the time and I have never been able to associate it with any single condition. As suggested it wouldn't hurt to check for vacuum leaks because even the slightest leak can cause this. If all else has failed the next place to look is at your MAF calibration. The closer your fuel trims are to zero at ldle on a reset, the less this happens and the less learning it needs to do. The other thing that can effect this greatly is injector latency, but that is not relevant unless you changed your injectors.

Other than that you will have to live with it but there is a way to limit the effect or eliminate it completely. Next time yor reset the ECU, Follow the below procedure and I guaranty you will almost eliminate this issue...

- Start the car and fully warm the motor first.
- Reset the ECU, shut the car off and wait 5 seconds.
- Turn the car on and wait 5 seconds
- Start the car and do not touch the accelerator peddle, Let it find idle on its own.
- Wait and let it idle for 3 minutes then give the gas a quick shot to 3000 rpm and let off the gas rapidly. It should drop to a stable idle and not fall below target. If it does it needs to idle some more till it learns its fuel trims and position.
 
Performance Machine in Hutto built the short block, I did the rest.
Thanks guys for the advise, I'll give it a go.
 

HolyCrapItsFast

Drinks beer!
I'll have a look when I get home from work. Can't view the logs from inside our firewall. :tup:
 

HolyCrapItsFast

Drinks beer!
Here are a few logs I did for MAF calibration. The first two are everyday driving and the last one I did at idle after an ecu reset.

https://drive.google.com/file/d/0B464AHZAcpy8Y3BzM0JNcmV3SGc/view?usp=sharing
https://drive.google.com/file/d/0B464AHZAcpy8Wl91OWk4RDQ1R1E/view?usp=sharing
https://drive.google.com/file/d/0B464AHZAcpy8WWxEVENtNmFjckU/view?usp=sharing

Even after reading, I'm unsure on exactly how in the software to make the adjustments..

Okay the adjustment to idle fuel is simple...

In ATR you are going to open the table for MAF Scaling. If you look in your log while at idle, you will see it is making corrections of about +7 to 8% at around 1.26 volts on the MAF scale. In ATR you simply increase the value at or around the 1.26 volt cell by multiplying it by 1.07. Then, to better smooth that with the rest of the scale, you highlight the values at 1.26 volts and the next 2 (two) higher cells and press "H" to interpolate the values. Then you highlight the values at 1.26 volts and the next 2 (two) lower cells and press "H" to interpolate the values.

Then save and flash the rom and follow my procedure above. You will see your fuel trims at idle stabilize much quicker. You might also think about raising your idle to something like 850. This keeps oil pressure up a bit more and it is a smoother transition from idle to acceleration. Don't forget to reset the ECU after a reflash always. You also need to make sure the car is fully warm before you log anything. Also please add RPM and Calculated load to any log you do.

You can also adjust this with live tuning but before I go over that you need to know how to do it this way to learn how because not every table in ATR is live tunable.
 
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THAT is what I am talking about. I knew from reading what able to change, but how to actually do it and smooth things out is not explained, or at least I couldn't find it.
 

HolyCrapItsFast

Drinks beer!
Yeah I wouldn't be going WOT anymore. There is knock everywhere.

Have you checked your injectors? Swap injector at Cyl 3 with Cyl 1 and see if the misfire follows the injector. Other causes of misfire are poorly gapped or dirty plugs or intermittent engine harness. Check your plugs and gap them to .028. Also unplug the main engine harness and spray it with some electrical contact cleaner and let it dry. Then spray it with WD40 and replug.

To tune and diagnose WOT issues you need to have a wide band AFR gauge and you also need to be able to log with it. You can get rid of most of those parameters in the log because the less you have, the more data will be recorded. It might help to add injector duty cycle for now just to make sure your injectors are adequate.
 
I appreciate the advise. How long have you been tuning or turning a wrench? I've been working on cars for some time, but I'm no pro. As far as tuning, I understand the basics, but I learn by watching and doing rather than reading.

I have an innovative wideband, but I need to hook a serial cable up to it. I'm going to get new plugs and start there. I still think it is a coil, I'll swap that first and see if it follows.. Those have been the culprit in the past. It only happens on load though.
what is the best way to clean injectors? If I need new ones, I'm getting larger ones and a new fuel pump.. thoughts?
 

HolyCrapItsFast

Drinks beer!
I appreciate the advise. How long have you been tuning or turning a wrench? I've been working on cars for some time, but I'm no pro. As far as tuning, I understand the basics, but I learn by watching and doing rather than reading.

I have an innovative wideband, but I need to hook a serial cable up to it. I'm going to get new plugs and start there. I still think it is a coil, I'll swap that first and see if it follows.. Those have been the culprit in the past. It only happens on load though.
what is the best way to clean injectors? If I need new ones, I'm getting larger ones and a new fuel pump.. thoughts?

Oh I have been tuning on a professional level since 3 years now but I have been doing it on an amateur level since I was 18. I started out on muscle cars and my first computer/turbo car was an 89 Dodge Daytona Shelby. From that point forward it was 4 cylinders all the way. Subaru are my passion though. I dedicated much of the last three years on Subaru tuning exclusively. I pride my self on creating some of the best street/daily driving tunes one can have. Regardless I am still learning new things every day and I will never stop improving myself or my work.

To clean injectors the best thing to do is soak them in carburetor cleaner and then WD40. That is about all you can do with out professional equipment. SeaFoam is another good cleaner. Another option would be to have them sent out for professional cleaning and flow testing.

Also it is always a good idea to replace your fuel pump no matter what. Especially if you are still using the stock unit. It begins to fall short on a Stage 2 tunes with stock injectors. If you have an 08 and above you can probably get away with the stock unit because the 08 and above flows more. But if you are replacing injectors on either the GR or GD, then I recommend a fuel pump regardless. If you are going to be using E85 then I recommend a large pump like a Deatschwerks 300 or an Aeromotive 340. For very high horse power like 500 or more, then I might even suggest dual pumps.
 

TK-421

New member
I've been tuning on the professional level for going on 6 years now. And just like [MENTION=9]HolyCrapItsFast[/MENTION] started tuning around 17 to 18 years old, only difference was I started out on 4 cylinders, and I started with things like Honda's using Hondata S300 management system. I really got my tuning in gear though when I started tuning Evo's. I learned to tune Evos to the point where I could almost do it in my sleep. Then I started to venture into Subaru's. After learning about the Cobb AccessPORT options, mainly because it was a rare thing to see on a CT9A Evo 8 or 9. But I started playing around with the beta version of ATR and eventually went to a certified instruction program that taught me the fine details of it, which in return certified me as a Cobb ProTuner. Over the past 6 years I've been tuning systems such as AEM, Hydra, Cobb, Opensource, Hondata, Chrome, LS Edit, GReddy EManage. Tuning isn't really some sort of witchcraft or magic, it's all about knowing the Limits of the engine. And the software your using.

As far as wrenching, I've been doing that for 15 to 16 years now, ever since I was 12. The difference now a days is im a ASE Certified Master Technician, along with having a Factory Technician training from Toyota and BMW. When it comes to actually turning the nuts and bolts I've been doing it forever.

I've also dabbed into things like Chassis Fab as well. Nothing too major, most of my fab work comes from making custom exhausts and Intercooler piping.

As far as fueling is concerned, I fully and 100% support what [MENTION=9]HolyCrapItsFast[/MENTION] has to say, I pretty much do most of the time. Smart man heed his words, and if your smart yourself, Id honestly let one of us take care of the tuning for you. Sometimes chasing your tail like this can lead to nowhere. The definition of insanity is doing the same thing over and over again and expecting different results.

I still think that you should also be checking the mechanical side of things. The small little things that are overlooked are usually what cause the big issues in the long run.

I would do a full work up on it honestly. Compression test, Leak Down, Vac Leak Test and Boost Leak test. Just to rule out mechanical issues with the vehicle, before pointing the finger at the ECU calibration. With subarus it can be something small and relatively insignificant that throws everything into a domino cascading effect when it comes to sensor calibration or even a fueling issue. Like stated above, check the main harness.
 
thanks again. I started working on cars when I was 17 but started on a 78 Chevy pickup.. I really started getting into wreching when I got my 99 Civic back in 02. I did a TON of research on tuning for those cars, but never had the funds to turbo my own car. I had a plan laid out and everything, but life happened and I ended up getting married bought a house and had a kid.. Now divorced and engaged and about to have 4 more step-kids.. lol.. I sold the civic back in 2010 and bought an 02 wrx and wanted more immediately.. We had a baby on the way and I had the money, so I bought an 05 STi from a Cobb Engineer. It was already stage 2 with Cobb everything.. I lost a lower rad hose last summer and never knew it since water temp sensors do not sense air temp... I pulled the motor and let a machine shop do their work on it and the heads.. I decided to go ahead and build it since it was apart and ordered a kit from AMS performance with JE pistons and Manley Rods. I let the machine shop build the short block and I did the rest.. 8000 miles later here I am and wanting to get a good tune under this thing.

Ive been working on computers for over 15 years and work in IT currently.. :)
 
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