Aracheon

It's in the same place on the sedan, in the trunk, driver's side.

Mike, what are you using for fuel pump control?

They don't last forever, evidently. Since it's a cheap and easy replacement, slapping another FPCM in there would be what I'd try next. (Assuming you don't want to plunk down a few Benjamins to replace it with an aftermarket unit.)

The voltage drop across the OEM unit was around 1.5v. It was around 1.0v on the first STi unit I bought. It was 0.1v on the second unit I bought. The second unit completely eliminated my fuel pressure problem, as the pump was finally seeing the current it needed to keep up.

Specifically, the 04 STi FPCM. The internal wiring is nearly 2x larger. I noticed significantly less voltage drop across the STi unit. This is all detailed in earlier posts in the thread, if you care to read it.

Logged in the sense that I watched my fuel pressure gauge rise and then fall as I was doing pulls, yes. I believe I detailed this in an earlier post in this thread. This. +1,000,000,000. eBay is where I bought both of mine... around $40 a pop.

Isn't this issue more prevalent with the 5MT guys? Sent from my SCH-I535 using Tapatalk 2

RTV... is there anything that stuff CAN'T do? I've been meaning to pull the rear door apart and check my wiring as a preventative measure.

Yep! Turned out that the first FPCM I bought was bunk. Bought a second replacement and the problems suddenly went away. Sent from my ADR6400L using Tapatalk

Thank you.

Where did you get that information from? (I'm not arguing or saying it's wrong, but I don't remember seeing that anywhere in the vacation pics.)

Yeah, I understand the manufacturing and cost logic behind it, but that certainly doesn't make it any less shitty. I used these ones: http://www.connectorsupply.com/catalog/butt-splice-heat-shrink-step-down-16-14-to-12-10-ga-p-480.html I think I paid $53 for the harness locally with tax. So $49 is in the ballpark.

Yeah, I just couldn't deal with it looking like shit. Yep - all 6 wires were spliced into the factory harness. Also yes, that part number is for the complete fuel harness, but it won't work with the Legacy in its entirety. I tried. It doesn't seem to line up. One obvious discrepancy is that the length of wiring from the grommet to the fuel pump plug is WAY too short to work on our car.

I was kicking myself in the ass for messing with the FPCM -> FP wiring in the first place after I started having all the problems, thinking it was something I had screwed up. Even if you look at the Impreza plug wiring, it's still quite a bit smaller than the overkill 10awg wire I'm using. It's probably closer to 14-16. If you can snag that plug out of a junkyard, it would probably be even cheaper than ordering an entire harness from Subaru - but it makes the wiring literally plug and play if you get some step-down butt splices. It's just my luck that I've had this much trouble with the car - it's been a nightmare since day 1. If this had been my first experience with a Subaru, it definitely would have soured me on the brand.

During testing I just shoved the wires into the vacancies left by removing the pins from the plug. My first iteration of soldering the 10awg wire directly to the pin didn't work as well as I'd hoped, as the pin holes barely accommodate the wire, much less the wire + the pin. Plus I wasn't very happy with how flimsy everything felt. The final product is the 08-12 Impreza fuel harness. The FP power wires are much thicker than they are on the '05 LGT harness, so I clipped the Impreza plug off about 6" away, and spliced into the thicker wires.