I have a '04 WRX w/STi block. Found out today (called dealer) my ECU is '02-'03 WRX. Talked with a Subaru tuner today who says to have an STi block I must have an STi ECU b'c the wiring is different. Not sure if the heads are STi or not. I'm running WRX intake mani. How's my car running so well?

MOD list:
Borla header
STi block
STi TMIC
STi pinks
VF34
Cobb TBE
Lightened Crank Pulley

Could it be possible I have an entire STi engine with WRX intake mani? WRX intake mani would be the only necessary piece on an STi engine in a WRX to avoid using electronic controlled throttle? Otherwise it could have the STi heads as well, correct?

 

please tell me you're running some kind of engine management, right? I'm pretty sure there are others running the WRX ecu with an STi block, and I believe it works because the main thing is that the ECU needs to see the right size injectors....I could be totally wrong though. However, it seems that if the wiring was wrong, the engine never would have been able to be put in.

If you do realize you need a different ECU, theres a guy in the NorCal classifieds selling an 05 STi ECU for $300

 

I dunno if there is engine management, though AFR's are perfect across rpm band in every gear. I pulled apart the center console and found a lot of wires spliced in and out a harness that also is intertwined with my Innovative WB. There's a red button w/a blinking red light, red&black wire, it's also spliced with other wires. Finally, a plug w/blk,blk,blu,grn,brn,ylw, and I think one or two other colors... the plug has some kind of lil' jumper wire/fuse/relay.

 

The EJ series engines are pretty much LEGOs. The STi shortblock bolts up to the WRX heads, engine mounts, etc. There is no electrical wiring issues unless you use the STi heads & Throttle body. It is the most common swap now days, is running a 2.5L STi engine w/ the WRX heads.

The Subaru 'tuner' you talked to is moron, I would not suggest talking to him again. It will save you money in the long run.

 

You may not need a different ECU, but you should seariously look into some engine management

 

The harness you speak of sounds like a turbo timer harness. The on times on the injctors are the same, you should not have any problems running a stock ECU. Some engine management will get you a hell of a lot more gusto out of your setup. currently the ECU is controlling as if there have been no changes made. Goodluck with your Hybrid, hopefully it is better to you than mine was to me.

 

red button with blinking light is probably a wideband? LC-1 perhaps.