It's been a long few months for my poor '06 STI. I originally bought the car in the fall of '07 and had nary a problem for more than a year. However late last year problem started creeping up...

Last fall my STI would occasionally start acting like it was out of gas at random times on the freeway, but the car still had 1/4 of a tank. Every time it happened I would fill up with gas and the problem would go away. At the same time, the fuel gauge would not register properly. (I knew that it was a 1/4 of a tank by the amount of gas I was able to put in the car not by the fuel gauge.)

The original thought was that the gauge and the sensor were not working properly. Those got replaced in December over Christmas along with some non-functional rear struts (so nice having suspension now). Problem fixed... we thought.

Fast forward a few weeks and my car starts to have difficulty starting at work one Monday. A co-worker jumped me and the car started up fine. Battery problem, right?

No, two days later I get in the car to go to work and it won't start, no matter what I do. I talk to Justin at Capitol Subaru and the tow truck comes to pick up my car (you may remember the pics of my STI on the flatbed). Justin tells me it's the fuel pump and that they have to order one, it'll be a couple days. No problem.

That Friday I come down to pick up the car with the brand new fuel pump and I drive off. Unexpectedly at 5500+ RPM the car balks and makes lots of bad bad noises. I turn around and take it back to Capitol (luckily i was just down the street at this point). I get a call a few days later and they tell me that they think the problem is that the aftermarket security system (installed in the car when I purchased it) is messing up the fuel injection. They unhook it (and I later removed it) and the car runs smoothly again, but within a few days starts having trouble starting again.

At this point I'm getting resigned to my car not working right and seriously comtemplated selling it and getting a different STI. But I take it back and we find that the fuel line isn't holding pressure, meaning that the valve in the fuel pump is bad. So in goes Fuel pump #3. For two days the car starts up just fine, then on day 3 it hesitates again, I can smell gasoline in the cabin, and the engine shuts down (scaring the crap out of me on I80) at 5500 RPM. But the car starts right back up again and I drive home sedately trying not to push the engine.

Last week I took in the car one final time and they discover we've been treating the symptoms of the problem. A check of the ECU finds that the fuel pump is at 100% load virtually all the time. A pressure check in the engine bay reveals that the Fuel Pressure Regulator is stuck closed, not allowing fuel into the return line. As a result the fuel pump had been pushing against the closed regulator and burning out the valve in the pump assembly itself.

After replacing the FPR and installing the 4th fuel pump in my car in 3 months, it's finally back to normal and I seriously hope I don't have to deal with something like this again!

 

Damn dude at sucks.... Was wondering where you went.. I figured they would have checked those systems out 1st. Ecu plug in and fuel psi check at the fuel rail. That would have been my first plan.

 

Yes, one would think, but it's hard to get mad now, it's fixed that's all I really care about. congrats to you by the way on all your stuff I read about!

 

I got about that far, said "Replace the fuel pump, pressure regulator, and filter". Glad you got it back finally, but seems like it wasn't FULLY diagnosed/repaired the first time around.

 

jeez. i hope its running properly now.

i agree with ^ it would have been niec with proper diagnosis from the beginning

 

Wow, lots of problems. Hope its okay now...

 

Haha next time i'll ask you !

 

Okay! And I dont charge $100/hour. haha