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03 XT Forester
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Discussion Starter #1
Car – MY03 Forester XT (155kw) OZ spec 180000km

Initially I wanted the car for both performance and off road so had it mapped to accommodate boost to 1.1bar (95 pump). Now priorities have changed so use it more as a family runaround and run with the EBC off so boost is governed by the actuator (+-0.4bar). if I use low boost (0.8 bar) I get FLKC as boost peaks at say 3000rpm but not higher in the rev range. Obviously with more boost the problem is more pronounced.

What is confusing is that when running with EBC (HKS) off (0.4 bar) I have noticed that the IAM drops, even when driving very gently (low engine loads) so just feathering the throttle and no WOT at all. Any ideas where to look for a problem? As the map is for 1.1 bar one would think that running 0.4 should be super safe and never see IAM drop. Any suggestions would be appreciated.
 

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05 FXT
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A timing map is setup that the timing increases as you decrease load and increase RPM.

It sounds like you're on a custom tune. If that's the case, when the tuner went through the tune, they probably did a few WOT pulls on the EBC to make sure the timing is good. They probably did not go through all of the load points w/ different boost levels to make sure everything is safe. Therefore in the lower load area's the map wasn't perfect.

In short, you probably need a retune.
 

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03 XT Forester
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Discussion Starter #3
agree, this is a possability. most of the tune was at WOT on road and dyno and noting / very little was one at low loads. Problem is car had a custom map when I bought it so my tune was for perfonrmance but also to ort out previous problem (as car was on limp on pump)


Actually at this point I would love to just put the original map back on if only I had it.
 

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2004 Subaru FXT MT
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1,841 Posts
A timing map is setup that the timing increases as you decrease load and increase RPM.

It sounds like you're on a custom tune. If that's the case, when the tuner went through the tune, they probably did a few WOT pulls on the EBC to make sure the timing is good. They probably did not go through all of the load points w/ different boost levels to make sure everything is safe. Therefore in the lower load area's the map wasn't perfect.

In short, you probably need a retune.
Yep, my thoughts too...
 

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2016 Outback and WRX CVT
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2,551 Posts
In short, you probably need a retune.
+1.


----

I also wonder about fuel grade/quality.

Similarly, I wonder about potential mechanical issues - aside from the outright mechanical problem, I wonder if either the knock sensor is corrupt and/or, if anything is tapped in to the ECU pinout for the knock sensor lead, i.e. a "knock-light" device, if either that device or its unshielded wiring could be causing feedback sufficient enough to corrupt the knock reading (don't laugh, this is actually very possible, and is exactly what happened to several early adopters of the TurboXS Knock/Shift-Light on the BL/BP Legacy).

Finally, can you pinpoint where the car's pulling timing?

Something big is going on, if it is severe enough to drop IAM......
 

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03 XT Forester
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Discussion Starter #7
Hi All and thanks for the responces

@ HArdrvin what is surprising though is that after the tune the car's IAM was solid for about a year, only then did it change

@TSI+WRX could be a mechanical issue given the above (though I still believe putting a stock map is a good starting point. I noticed on cold mornings a "ticking" from the motor which dissapears withing say 30 seconds once the car warms up, thought it could be roller valves maybe the noise sets of the knock sensor? Our fuel quality also sucks but I try to stick to the same filling stations so that quality is as constant as it can be
 
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