Crackling Turbo? Impreza WRX

[edar]

It's me again,

After asking for your advice a few weeks ago on a dodgy alarm/immob I need your help again.

Basically I've been hearing a noticeable crackling noise from what I think is the turbo when I accelerate from a standstill and mid-range (2003 Subaru Impreza WRX standard with stainless steel exhaust). It appears to come in at 4000rpm to 5500rpm, sometimes at 3000, but when it occurs I then get a quite substantial loss of power. The last time it happened it took 24 hours for that mid-range power surge to return. It's not so bad in the cooler weather but now we're seeing temperatures of 20-28 degrees, it's certainly more prominent. It's happened about four times now over a period of several months. I was thinking catalytic converter, turbo (not boosting) or cat sensor? My subaru garage don't know and there's no engine light coming on when it happens. I've also spoken to a few specialists and they're none the wiser. Can anyone shed any light on this or am I looking at a lengthy and costly diagnostic fault finding drama.

Your help would be much appreciated. Thank you..

[forty-two]

Mine had a light rattle that only happened over 3000rpm. I thought it was a loose heatshield or something like that...

Turned out to be big ends. 60k 2004 WRX Waggon.

[scoobydude]

My guess would be a cracked wastegate housing.

[Marf]

"Crackling" followed by lack of power that takes a while to return?

Knock. ECU retards timing, which reduces power, power returns as the ECU advances the timing again.

[trickywoo]

Marf said:

"Crackling" followed by lack of power that takes a while to return?

Knock. ECU retards timing, which reduces power, power returns as the ECU advances the timing again.

That would be my guess as well. Often followed by a rebuild.......

[Marf]

What kind of fuel are you using?

What gears are you in when you hear it at the rev ranges you specify?

[ScoobieWRX]

Could be a crack in the exhaust headers or uppipe. If the crack opens right up under the intense heat and presssure from engine loading and revs when just about to boost fully it's very possible you could get a crackling noise and a loss of power.