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Old 11-27-2018, 07:30 PM   #1
alexmartynyuk
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Join Date: Oct 2008
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2005 EVO VIII
Apex silver

Default 05 sti IAM drops to ZERO

05 sti
Pacific North West(rainy and 50 degrees)
92 octane pump gas
dom 2.0xt
process west tmic
perrin big maf
tgv delete
AEM 320 fuel pump
FIC top feed fuel rail conversion
FIC top feed injectors (i believe they are 1000cc)
Tial EWG 38mm
Grimmspeed 3 port
Catless downpipe
3in exhaust
Supposedly upgraded pistons and rods

Hey guys and gals. I mostly tune evos but occasionally help out my friends that own subarus and need any tuning done. One of my close friends recently acquired an 05 sti with the mods listed above. The car was previously tuned by a local shop near by but needed to be retuned because it was running 26psi on straight pump and was stumbling bad due to knock. Supposedly this car has upgraded pistons and rods but I have not confirmed this myself. I started to tune from scratch because the rom tuned by the shop needed their definitions to be able to view it. As I got the car running and tried to do some pulls I found out that ignition advance multiplier drops to zero pretty much immediately after .61 g/rev. I have tuned several subarus over the past few years and never had the iam drop to zero. I inspected the knock sensor to make sure its tourqed down properly which it is, nothing is loose around it. Has anyone experienced anything like this? On the evos you can desensitize the knock sensor, is there a way to do that on the sti? I know for a fact that there is no knock at that low of an engine load with the timing its running so it shouldn't drop like that. The engine itself runs good, no abnormal noises or anything like that. I know that built internals might trip the knock sensor into picking up false knock, how do you guys go about that without disabling the knock sensor completely? Any input/help would be greatly appreciated guys! Here is a link to the same thread I posted on romraider with a map and log attached.

http://www.romraider.com/forum/viewt...p?f=15&t=15249
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Old 11-27-2018, 08:34 PM   #2
BURNING4ORCE
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Look at knock settings based on load = fbk, flk, and rough and you can also do rpm. If you want to desensitize the subaru knock sensor since its a built motor there is a write up somewhere.

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Old 11-27-2018, 10:34 PM   #3
alexmartynyuk
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Apex silver

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Yeah thanks. I really don't want to physically handicap the knock sensor with the nylon washer or moving it. Just wanted to know if you can adjust it just enough to get rid of false readings. How did you attach the image?
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Old 11-28-2018, 08:43 PM   #4
BURNING4ORCE
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You want the knock sensor where it's at and clocked at the right orientation for sure. With the setting I provided in the attached image it should get rid of the low load knock situation.

You can use postimage, imgur, tinypic, and etc. for attaching pictures here.
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Old 11-28-2018, 11:41 PM   #5
alexmartynyuk
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Thanks will try it tomorrow and report back. The knock sensor is facing the right way. I have not checked the tq. Is there any other reason iam can drop other than knock and an active cel?
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Old 11-29-2018, 07:28 PM   #6
alexmartynyuk
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Well I messed with the car for a few hours today and didn't really get any further. IAM kept dropping to zero. I kept bumping up Feedback Correction minimum load, each time that value was exceeded during the pull IAM dropped to zero. I also tried to run knock correction advance alternate mode but the 3 port wasn't responding as if it was still disabled by low IAM. Speaking of the 3 port eventually I bumped Feedback Correction Minimum Load to 3.5 just to see if I can get the 3 port to work so that I know if its being disabled by low IAM and I did a pull and it worked and then went back to wastegate pressure after like 5krpm. At this point I'm really upset, I'm gonna put a hallman on it and run 19ish psi and really conservative timing and finish the maf scaling and tip in and all the other fuel related tables.
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Old 11-30-2018, 03:24 AM   #7
BURNING4ORCE
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I understand your frustration. Maybe the knock sensor is bad? Or check the wiring on the sensor itself. If the motor is noisy then you most likely need to numb down the knock sensitivity along with some detcans and go on from there.
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Old 11-30-2018, 11:52 AM   #8
86Dreams
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A couple things I want to throw at you:

try unplugging the knock sensor. I think it will run normal with a CEL, then check your knock readings, if youre still getting knock maybe theres some other problem. Likewise you could just replace the knock sensor.

Ask on Rom Raider if anyone knows how to modify your ECU definition to include the knock sensitivity tables.

In general your maf needs some serious work. you might want to zero out the manifold pressure comp table to account for some of the inconsistency you find.

Your KCA Table isnt lined up with your base timing table. Zero out the KCA 1.0 g/rev column, its causing a spike in your timing at that load.

also when you log log voltages for battery and maf as well as avcs
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Old 11-30-2018, 12:37 PM   #9
alexmartynyuk
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Quote:
Originally Posted by 86Dreams View Post
A couple things I want to throw at you:

try unplugging the knock sensor. I think it will run normal with a CEL, then check your knock readings, if youre still getting knock maybe theres some other problem. Likewise you could just replace the knock sensor.

Ask on Rom Raider if anyone knows how to modify your ECU definition to include the knock sensitivity tables.

In general your maf needs some serious work. you might want to zero out the manifold pressure comp table to account for some of the inconsistency you find.

Your KCA Table isnt lined up with your base timing table. Zero out the KCA 1.0 g/rev column, its causing a spike in your timing at that load.

also when you log log voltages for battery and maf as well as avcs
Oh yes lol, i know the maf needs scaled, its got a perrin big maf so I did some rough math to get it into the ball park, but with 10psi you can only scale it so much. I spent a little time yesterday, its not gonna look perfect anyway, I have no clue what size the injectors are but I have them scaled at 1150 to get close to the target in the open loop map. I zeroed out the kca table completely and redid the base timing map, once the mbc shows up Ill finish the car as planned. I work really long hours and don't have that much free time to mess with it. Not how I wanna go about doing this but it will have to do. I skipped a few perameters to log because this laptop sucks and when I select more parameters it freezes up on me lol. Thanks for all the input guys. I feel like IAM is dropping for some other reason other than knock.
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Old 11-30-2018, 01:19 PM   #10
86Dreams
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Quote:
Originally Posted by alexmartynyuk View Post
Oh yes lol, i know the maf needs scaled, its got a perrin big maf so I did some rough math to get it into the ball park, but with 10psi you can only scale it so much. I spent a little time yesterday, its not gonna look perfect anyway, I have no clue what size the injectors are but I have them scaled at 1150 to get close to the target in the open loop map. I zeroed out the kca table completely and redid the base timing map, once the mbc shows up Ill finish the car as planned. I work really long hours and don't have that much free time to mess with it. Not how I wanna go about doing this but it will have to do. I skipped a few perameters to log because this laptop sucks and when I select more parameters it freezes up on me lol. Thanks for all the input guys. I feel like IAM is dropping for some other reason other than knock.
Good luck then.

When you get down to it check out this on RR http://www.romraider.com/forum/viewt...p?f=32&t=13450
its kind of hard to use but it can help you to form a very nice curve for your maf.
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Old 12-01-2018, 12:31 AM   #11
alexmartynyuk
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Quote:
Originally Posted by 86Dreams View Post
Good luck then.

When you get down to it check out this on RR http://www.romraider.com/forum/viewt...p?f=32&t=13450
its kind of hard to use but it can help you to form a very nice curve for your maf.
Thanks buddy, definitely will. I usually hate scaling maf lol. I'm used to the tephra 3d speed density rom on the evo. I know theres merp mod but i need time to get familiar with it, and this car needs to get tuned ASAP so probably another car for a later time lol.
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Old 12-01-2018, 12:42 AM   #12
Homemade WRX
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I'm just over hear, pulling my head out of mechanical side of engine building and reading. Keep up the good discussion
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Old 12-01-2018, 02:59 PM   #13
NSFW
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ATP 3076, 6MT, AVO FMIC

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If you've got an engine stethoscope and a known-good motor, try listening to both motors. If the engines sound about the same, then you probably just have a sensor problem.

It would also be interesting to watch what Knock Sum is doing during idle and cruise. Tune those very safe, raise the bottom of the knock learning RPM range to 3500 RPM, and cruise around a little bit. If it's normal to see Knock Sum increment sometimes when shifting, and occasionally when cruising, but for the most part it should be pretty quiet. If it's counting up rapidly that would indicate a noisy motor or faulty sensor.

It might also be interesting to log the Knock Sum parameter and see if it is rapidly increasing at the same time IAM goes to zero. I'm pretty sure you'll find that it is, but if it's not... well that would be weird. But the more interesting question IMO is whether it's always rapidly increasing.


I thought IAM was only supposed to drop if there are many cells in the knock learning table that had negative values, so it's weird that you're seeing a drop right after entering the correction range. I think you've discovered a new feature that's always been there, but nobody has had a noisy enough engine or a bad enough sensor to see it happen until now.
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Old 12-01-2018, 04:25 PM   #14
alexmartynyuk
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Quote:
Originally Posted by NSFW View Post
If you've got an engine stethoscope and a known-good motor, try listening to both motors. If the engines sound about the same, then you probably just have a sensor problem.

It would also be interesting to watch what Knock Sum is doing during idle and cruise. Tune those very safe, raise the bottom of the knock learning RPM range to 3500 RPM, and cruise around a little bit. If it's normal to see Knock Sum increment sometimes when shifting, and occasionally when cruising, but for the most part it should be pretty quiet. If it's counting up rapidly that would indicate a noisy motor or faulty sensor.

It might also be interesting to log the Knock Sum parameter and see if it is rapidly increasing at the same time IAM goes to zero. I'm pretty sure you'll find that it is, but if it's not... well that would be weird. But the more interesting question IMO is whether it's always rapidly increasing.


I thought IAM was only supposed to drop if there are many cells in the knock learning table that had negative values, so it's weird that you're seeing a drop right after entering the correction range. I think you've discovered a new feature that's always been there, but nobody has had a noisy enough engine or a bad enough sensor to see it happen until now.
Yeah Iíll log knock sum next time I see the car. Yeah this behavior is weird, never had it happen before to any car. And the thing is this engine is really quiet, even when cold. Itís frustrating tho cause I have other things to do on my days off other than messing with this thing.
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Old 12-01-2018, 08:37 PM   #15
NSFW
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If the engine sounds quiet and knock sum is increasing, I think I'd start by replacing the knock sensor.
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Old 12-15-2018, 02:06 AM   #16
BMXspears
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I know you mentioned that the knock sensor was properly installed, but is it clocked the right direction? I tuned a car the other day that was not, and it was registering knock at very conservative timing numbers. Customer rectified it, and it was able to run expected numbers.

Also, if you want that map unlocked you can send it to me.
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Old 12-17-2018, 12:18 PM   #17
alexmartynyuk
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Quote:
Originally Posted by BMXspears View Post
I know you mentioned that the knock sensor was properly installed, but is it clocked the right direction? I tuned a car the other day that was not, and it was registering knock at very conservative timing numbers. Customer rectified it, and it was able to run expected numbers.

Also, if you want that map unlocked you can send it to me.
Yes sir, clocked correctly, I couldnt verify if it was tqd down correctly tho.
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