Misfire at 4k on my wrx totally stumped HELP!!!!

[Thefatmanwrx]

Hey they im new to the forum and im looking for some help. Right my problem is a consistant misfire at 4k in any gear underload but no cel at first i thought plugs so i replaced them problem still persists then i thought id change the coil packs so i did still no change ive also replaced the maf and front 02 sensor and the problem stil persists its driveing me insane ant help would be appreciated thanks in advance...... could it be the crank posistion sensor on its way out ?????????

[Scoobyghost]

What plugs did you replace them with?

[Thefatmanwrx]

40 minutes ago, Scoobyghost said:

What plugs did you replace them with?

I replaced them with ngk irridium tips thanks for the reply 

[savage bulldogs]

Heat range 6 or 7 plugs ?

 

Are you running stock boost and map ?

 

Any mods ?

[Thefatmanwrx]

3 hours ago, savage bulldogs said:

Heat range 6 or 7 plugs ?

 

Are you running stock boost and map ?

 

Any mods ?

Heat rage 7 and running 20 psi boost , td05 turbo 

[Tidgy]

1 hour ago, Thefatmanwrx said:

Heat rage 7 and running 20 psi boost , td05 turbo 

how has the boost been turned up?

[Thefatmanwrx]

It has been tuned by previous owner  aparently

15 minutes ago, Tidgy said:

how has the boost been turned up?

  but has been perfect up until about a week or so ago 

[Thefatmanwrx]

Ive been told it could be crank sensor on its way out ??

[Tidgy]

ah k, something has changed them, could be crank sensor but could be alot of other things :(

 

Can you get it to a specialist for a diagnosis? (and i dont just mean computer says jobbie)

[Thefatmanwrx]

3 minutes ago, Tidgy said:

ah k, something has changed them, could be crank sensor but could be alot of other things :(

 

Can you get it to a specialist for a diagnosis? (and i dont just mean computer says jobbie)

Ive had it plugged in it came up with no codes thats why im so confused thanks for the reply 

[Tidgy]

Won't always throw up codes, that's why you need a specialist. My car had a misfire but no codes and turned out to be a duff leed.

[Thefatmanwrx]

6 minutes ago, Tidgy said:

Won't always throw up codes, that's why you need a specialist. My car had a misfire but no codes and turned out to be a duff leed.

Cheers ill have to look up a local specialist .i assumed my model doest have leeds with it haveing 4 coil packs rather than the single like the classics 

[Tidgy]

yeah different setup. doesnt meaa one of them might not be duff though

[Thefatmanwrx]

7 hours ago, Tidgy said:

yeah different setup. doesnt meaa one of them might not be duff though

They shud be fine i replaced all 4 with genuine subaru ones from importcarparts this car has me totally stumped off to a specialist it goes (when i find one 😣) but on the other had ive ordered a new crank posistion sensor so fingers crossed 🖒 just removed my crankshaft sensor under the alternator and it has a small dent in it could this be whats causes my issues 

[savage bulldogs]

Crank /cam sensor faults normally throw up a code . Having a different turbo and more than stock boost it should've been mapped  (fuel adjusted to suit the extra air ) . 

Do you know if it has been mapped ? 

If not and it was running ok , have you recently reset the ecu or disconnected the Battery ? 

As the ecu might have "learnt" the mods  to protect the engine and a reset would take it back to factory map .

 

[Thefatmanwrx]

1 hour ago, savage bulldogs said:

Crank /cam sensor faults normally throw up a code . Having a different turbo and more than stock boost it should've been mapped  (fuel adjusted to suit the extra air ) . 

Do you know if it has been mapped ? 

If not and it was running ok , have you recently reset the ecu or disconnected the battery ? 

As the ecu might have "learnt" the mods  to protect the engine and a reset would take it back to factory map .

 

Cheers for the reply id say its definately been mapped its ran well for the last 12 months and yes the Battery has been disconected a few times clutch head gaskets etc its a confusing one 

[Thefatmanwrx]

So just an update replaced crank sensor still the same 🤔so its off to adgespeed tuesday hopefully they can figure it out..thinking now it could be fuel related fuel pump or fuel pressure regulator or maybe both or maybe the timeing has skipped a tooth god knows hopefully they get to the bottom off it 

[Thefatmanwrx]

ITS ALIVE!!!! so thanks to the guys who suggested it was a tunning issue because it was just that apparently my cars ecu was hunting for vvt which it doesnt have god only knows why this happend because was running fine but hey thats life glad alls fixed and back BOOSTING 😀 adgespeed saved my life