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"boost cut when under the MAP limit" LINK g4+

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Hi guys ! dont know if im missing something here and this wrx sti keeps giving me new problems everytime i start it or fix a previous one.. there have been alot of people messing with this subaru 1998 wrx sti ej22 and stuff wasnt done right.. so the latest problem i have is just when i started tuning it on boost ( org boost solenoid unpluged ) it started to hit a limit everytime i go past 4500 rpm and go in to a little more then 1 bar of boost.. i have the log and the started file attached.. do you guys see anything that is wrong or something i have missed ?

the car started tu push water from the turbo so i cant really test drive it more then the logging i have now.. sry !

Best regards Leo

Attached Files

Hi Leo,

Was is actually "limiting" in that log you attached? I dont see anything wrong in the log or map. There are none of the common symptoms of trigger errors, there are no limiters active, pulsewidths, ignition timing, dwell and lambda all look rock solid.

There is one count of RPM limit saved in the map/ECU statistics (12700RPM!), so it appears there may have been a trigger error at some point but there is no sign of that in this log.

i have been going crazy looking trouh the map and i couldt spoot anything wrong with it either.. but the only thing i could come up with is that i must have done something wrong when setting the limits or something thats why i wrote it becouse it feels like a really hard boost cut and it is always on 4500rpm.. i cant figure out why its cutting.. im out of ideas and i thing that i need some fresh eyes and some points on what to do now, i really appreciate your comments and for the time you took looking trouh the files ! got any ideas on what to check ? i think i have been working on it to much so i have come to a dead end in my mind..

thansk one again !

The log that was attached to your original post - was the engine actually doing this "limiting" effect in that log?

I have run your map in a ecu here connected to a simulator at high RPM and boost to confirm there is no limiter setting you have missed.

I would probably be looking at the ignition system, see if smaller plug gap helps etc.

ooh that was a nice feature! yes when everything dropps down in the end is when its happening, cant hear any knock or something it just dropps down and wont go past 4500rpm :S

i have new ngk bcpr7es with 7mm installed !

Link starts to cut begining at 0.2bar under limit, but most peobabbly ypu have tho.change voltage or filter at crank trigger. Common problem on subaru

Link starts to cut begining at 0.2bar under limit, but most probablly you have to change voltage or filter at crank trigger. Common on subaru with link ecu

thx for thee tips claudiu ! when looking throu the map and the log i cant see any registred limits achived or any signs off trigger issues, can it still be some kind of problem with the trigger ?

I ran through the same problem or similar it was my clutch switch and launch control if you have it setup it might be the problem mine runs beautiful until it hits the launch control limit and it does fuel cut sorry I didn't open the file since I'm using my phone hopefully you already passed this issue

I can't see any limiters or your launch control activating so I'd start investigating either an ignition break down or your head gasket failing

Attached Files

Have you checked that the blow of valve is propperly sealing? The sudden boost droop looks like boost is escaping. Looking at the last bit of the log the map is actualy flatening out at 100kpa just before the throttle is closed. Indicating that the air migth be ecaping to atmosphere.

I would check the bov, and the check the vacume lines to the bov and wastegate for cracks.

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