been awhile since posting here, but I need help from people that know the EJ20K motor in a Version IV STi Wagon with 50,000 kilometers on it.

Car was bone stock except for an exhaust until last month, I had the following work done:

Timing belt
tensioners
timing guide replaced
NKG-R plugs and new wires
Greddy Profec B Spec II Boost controller added
FMIC installed (used item)
Blitz BOV (atmospheric) (also used item)
HKS intake
Apexi Power FC (also used item)

above 3000 rpm's the car is fine and pulls strong. Below 2500rpms it likes to hunt a bit at idle and then stall. Also when at a stop light when you try to accelerate (under normal load) the car also likes to hesitate, sputter and often stall.

my tuner wants to run a VG30DETT MAF, Fuel regulator, Upgraded fuel pump and injectors...

I am really hesitant to do this, because of the car not having issues above 3000rpms.

from the internet the following seems likely:

MAF going bad
IACV going bad
O2 Sensor going bad
Vacuum leak

One thing I did find was that the atmospheric BOV was not set and was leaking badly at idle, closed it down and car was fine for about 30 minutes. Definitely going to replace that with a recirculating BOV.

Can you think of anything else I should look at that might be causing these problems?

Only one Tuner in the area and I really don't trust him at this point anymore.

Appreciate any help. I am currently out to sea and just trying to narrow down what I will need to look at.

Thanks in advance for any ideas.

Try your throttle body solinoid

Had the same problem, and gradually got worse,
Cleaned out my throttle body solenoid and that did the trick, had that much crap I'n it.

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my05 STi
my13 Rok

:)

Did you do the full 30 minute idle learn on the power Fc?

also if the bov was leaking at idle, sealing it may have it running uber rich down low.

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[CENTER][SIGPIC][/SIGPIC][/CENTER]
[CENTER][COLOR=#ff0000]Built Ej207: Semi-closed RA Cases - Wiseco Forgies - Manley rods - BC 272 cams - GDA Heads - billet f/whl - Vi-pec - WbO2 - 800cc Yellow tops - TD05-20G - 409Hp ath @ 1.75bar on E85[/COLOR][/CENTER]

ok, buddy of mine is trying to trouble shoot the car while I am out of country.

He swapped the stock ECU back in and the car seems to be fine, but is displaying a check engine light now.

he's not sure how to check CEL codes, and I am having a hell of a time finding a thread on it, does someone have a link to the process?

Looks like my PowerFC is bad, or badly tuned...

Rossco - found your write ups on reading ECU codes on the GC8...thanks!

Which CEL came up?

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[COLOR="Gray"]550Nm off a 2L... Just wish it was in the dak dak...[/COLOR]

haven't been able to check yet. I'm currently out to sea (in the US Navy) and won't get a chance for a few more days.

Ok, the fact that a CEL came up with the stock ECU points to a failure somewhere that isn't related to the PowerFC or the tune.

Get the code, fix the part, do heli's until something breaks again

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[COLOR="Gray"]550Nm off a 2L... Just wish it was in the dak dak...[/COLOR]

Error code 44 waste gate control solenoid valve

Because someone has unplugged the vacuum source to the pressure exchange solenoid & boost control or left them unplugged from the wiring loom.

The pfc uses the factory map sensor for boost control so I suggest someone has played with the vacuum lines & cocked them up which caused your original issue.

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[CENTER][SIGPIC][/SIGPIC][/CENTER]
[CENTER][COLOR=#ff0000]Built Ej207: Semi-closed RA Cases - Wiseco Forgies - Manley rods - BC 272 cams - GDA Heads - billet f/whl - Vi-pec - WbO2 - 800cc Yellow tops - TD05-20G - 409Hp ath @ 1.75bar on E85[/COLOR][/CENTER]