FFS 9 psi?

I've done some research before on this and never really figured it out. Im on Cobb stage 2 93 oct OTS map. 05 Sti. When I use the Flat Foot Shifting, after I shift my peak boost is only 9 psi. I think I have it set to 5000 rpms. I hardly ever use the FFS any ways, I was only curious what could be causing it to boost so low. When I shift normally everything is fine and boost stays between 17.5 and 18 psi. Any one else ever had this problem?

Curious to hear what people have to say. I've never FFS before and have only "2-stepped" once when I first got the car. (Not my thing...)

boostCreep said:

I've done some research before on this and never really figured it out. Im on Cobb stage 2 93 oct OTS map. 05 Sti. When I use the Flat Foot Shifting, after I shift my peak boost is only 9 psi. I think I have it set to 5000 rpms. I hardly ever use the FFS any ways, I was only curious what could be causing it to boost so low. When I shift normally everything is fine and boost stays between 17.5 and 18 psi. Any one else ever had this problem?

Click to expand...

Is your car tuned or is this an off the shelf map? When FFS is active, it is a fuel cut limiter. What is happenning is you are knocking... or the ECU thinks it is knocking and the ECU is evoking fail safe and is cutting waste gate duty cycle forcing waste gate pressure only. If you monitor the parameter "DAM" or Dynamic Advance Multiplier on the AccessPort and you will likely observe it to be well below "1". 1 is ideal and that is were it should be all of the time unless you have bad gas or other mechanical issues.

Can you post a log of when you FFS?

I'm on cobbs off the shelf stage 2 91 oct map. I was on 93 oct but went back to 91 because I am unsure of the gas quality around me but I still put 93 in it. I can do a log with FFS active and post it up in the next few days.

As others have mentioned... 9 PSI is close to waste-gate pressure. I'd be concerned that your IAM (DAM) is under 0.5 and the ECU is pulling boost.

How can this be fixed? Get a protune or go open source ?

My first suggestion would be to have a boost leak test done and it probably might be a good idea to get a compression test done as well just to rule out any issues and give you a good base to refer to in the future. Then you should probably have a pro-tune. Since you have the Cobb already there is no need to go open source. Cobb and Open Source are just the methods used to get a tune on the car. The pro-tune is what you need.

It would be helpful for us to see a log and since you have the AccessPort you might want to try your hand at logging with it. Below is a link to a guide to logging that should help you out

http://igotasti.com/vBforum/showthread.php?213-Newbies-Guide-to-Logging

I've got plenty of logs I just don't have any while FFS is active. I did a compression test a couple weeks ago when I changed plugs and everything was good. Like I said it only boosts to 9 psi after I shift when using FFS. If I don't use FFS and shift normally everything is fine. Not throwing a cel either.

I will get a log while using FFS sometime this week and post it up. Thanks for the link on logging too by the way.

So I got some logs finally. I took a couple the other day because I flashed it to the stage 2 93 oct map just because I never have. Since ive had the AP if always ran the 91 oct map because I am unsure of the gas quality around me. So I reflashed it back to the 91 oct map and did some logs.

This is the first one I did. 4th gear pull.
https://docs.google.com/spreadsheet...N1Yqsw1ZTUnrhHeaottny73B4U/edit#gid=339375066

Everything appears normal, except for the little knock at high rpm

This is the 2nd log, 1-4 pull. Something is going on...
https://docs.google.com/spreadsheet...FZ6kBRKkAd9Zh9pmnQgMiURpU/edit#gid=1648450054

Then I realized im not reaching target boost, so did another one yesterday.
https://docs.google.com/spreadsheet...tD9F4qrWfIgiwbHOnZn7pbhdU/edit#gid=1828655573

Something is up and im not sure. And these logs are not using FFS. This is shifting normally.

[MENTION=9]HolyCrapItsFast[/MENTION]

Dynamic advance dropped to .5 . This is a bad thing and indicates a significant knock event at some point prior to this log. You have some other things going on and we can figure it out for you if you take a few more logs for us...

Please do not go WOT any more until we can figure this out. I fear you are close to damaging your motor if you do.

What I would like for you to do is to take another log of normal around town driving. You can go into light boost but not to offten. Do about 15 minutes worth of driving.

Please log the following only...

• A/F Sensor 1 Ratio
• Air Intake Temp
• Boost
• Calculated Load
• Closed Loop Fuel switch
• Dynamic Advance Multiplier (DAM)
• Engine Speed (RPM)
• A/F Correction 1
• A/F Learning 1
• Ignition timing
• Injector Duty Cycle
• Dynamic Advance
• Feedback Knock
• Fine Knock Learned
• MAF Voltage
• Throttle Position

Alright I'll do that. And my dam is reading 0.5 in the third log because I reflashed the tune and did the log shortly after.

[MENTION=9]HolyCrapItsFast[/MENTION] you're awesome.

I will post up the new log next time I drive the car. It's not my daily and has been spending its time in the garage due to the dumpy rain.

boostCreep said:

Alright I'll do that. And my dam is reading 0.5 in the third log because I reflashed the tune and did the log shortly after.

Click to expand...

Okay do me a favor... Don't reset the ECU anymore until we observe DAM to increase. If it increases that is a good thing and the higher it goes the better. Ideally when it does change it should go right to 1 unless something holds it back.

got two more logs here is the first one. It was only about 10 mins long.
https://docs.google.com/spreadsheet...M9_KtbymXzF11cjOCSAqnttLE/edit#gid=2111310302

Did another one for a full 15 mins. My DAM dropped...
https://docs.google.com/spreadsheet..._x3s8p8xzg8I4M93XoNPii050/edit#gid=1769177649

In the future, it is a good idea to log only the parameters necessary to diagnose the issue. Logging excess parameters only serves to cut down logging resolution. /PSA

Took a look at your logs. The second log is only cruise, so not a very useful log in my book if only to look at the LTFTs and STFTs. Both fuel trims look reasonable at cruise (unlikely you have a gross vac leak). Your DAM (IAM) drops immediately after ramping up the load during throttle on. Firstly, no forum warrior truly knows the way Subaru ECM strategy splits FBKC, FLKC, and IAM. The fact that IAM pulls timing without registering FBKC and FLKC may be due to the load cells in which the knock is present. Since you are at low load, FBKC and FLKC are disabled. I pulled open a stock 2005 STi map to demonstrate:



Admittedly, I don't know what the load cells Cobb's map is set to register FBKC/FLKC, but I would assume it's similar to stock. Excessive knock sensor chatter at low loads is usually due to rattles in the engine bay, not necessarily detonation. A useful parameter to log in the future would be the Knock Sum parameter. I don't know if this parameter is available in pre-CAN 32 bit ECUs (it wasn't available in the 16 bit ECUs). So, a couple thoughts:

1. I would check your engine bay (particularly the heat shields) for rattle that may contribute to false knock
2. Next log should include Knock Sum if available
3. When was the last time the Spark Plugs were replaced? Bad spark can contribute to a non-repeatable flame front as can carbon buildup in the valves in pistons. Have you ever sea-foamed the car?
4. Without a WBO2 sensor, it's difficult to diagnose this, but throttle-on knock is often caused by poor tip-in tuning. Tip-in changes based on injectors and modification to the intake system. Can you confirm that you are not running an aftermarket intake, post-MAF hose, or turbo inlet?

Spark plugs were replaced last spring. About 8k ago. Did a compression test at that time and all cylinders were good. I have never sea foamed the car. I am running a spt short ram intake. It came with the car when I bought it so I do not have the stock intake. The turbo inlet and everything else all appears to be stock to my knowledge. The only mods I have are a turbo back catless exhaust and the spt intake. I did have the turbo rebuilt last spring as well by six star speed. I think I'm just do for a protune to get everything back in line and ditch the cobb ots.

boostCreep said:

Spark plugs were replaced last spring. About 8k ago. Did a compression test at that time and all cylinders were good. I have never sea foamed the car. I am running a spt short ram intake. It came with the car when I bought it so I do not have the stock intake. The turbo inlet and everything else all appears to be stock to my knowledge. The only mods I have are a turbo back catless exhaust and the spt intake. I did have the turbo rebuilt last spring as well by six star speed. I think I'm just do for a protune to get everything back in line and ditch the cobb ots.

Click to expand...

However, at this point, if you have a mechanical problem a pro-tune will not resolve the issue. I would first check the engine for rattles. This might be a good time for you to invest in a WBO2 sensor. With the WBO2, we can really look at the tip-in and make adjustments.

Interestingly I've never been impressed with the stock MAFv calibration and the IAT MAF compensation, but I've never seen it cause that much havoc on the IAM. I suspect something else.

EDIT:
Just to clarify once more, the first thing I'd suggest you check is the heat shield on the turbo. Since it's stage 2, you had four options:
1. Modify the stock heat shield
2. Remove heat shield entirely (not recommended)
3. Run aftermarket heat-shield
4. Run turbo blanket

Which option did you take? As you can see here, the knock sensor is very close to the turbo heat shield (the brown connector in the middle):

I am running a cobb turbo heat shield. I do have a aem uego wideband as well. Readings are normal at idle but goes full rich (10.0) at wot.