ok my sisters 01 outback stopped running Tuesday. it would start and then die. First thing I did was check fuel pressure, it had none. I replace the stock pump with a walbo 255 cause I had one on the shelf. still no pressure. it will pump a lot of value but you can hold your thumb over the supply hose and it doesn't push out at all. I have spark, compression, injectors are firing just no pressure. is there anything else between the pump and the fuel filter in the engine bay where it has a relief? thought Id ask before I tear to far into it. thanks
I got no pressure before the FPR that's the problem. I though the same thing. im running out of good ideas. I think im going to have to pull the line back out from the sending unit and see if I got pressure there, maybe a crack in the ending unit housing and its flowing back into the tank?
I don't know a ton about fuel pumps, but I know that gen Outback has a persistent issue with an O-ring in the fuel pump, I would surmise that if the Walboro didn't solve the problem that this is not the issue. May be worth asking on the subaruoutback.org threads though http://www.subaruoutback.org/forums/110-gen-2-2000-2004/41182-symptoms-fuel-pump-o-ring-problem.html
You can disregard my previous surmise that ruled out the O-ring. It could still be the O-ring, since the o-ring would not be affected by swapping pumps according to this thread. You should replace it with a Viton O-ring. It's possible you also cracked the cap on the housing. These seem to be the two most common causes of failure on that pump/housing from what I've read. Many who have attempted to preventative replace that O-ring have cracked the cap in the process so it'd be worth visiting a U-pull it yard and having a spare on hand just in case when you go to do this. http://legacygt.com/forums/showthread.php/walbro-fuel-pump-install-127809p4.html
Check to see if you have pressure between the filter and pump. Fuel pump module has a bad o-ring seal on the pressure cap, check for crack o-ring and cap.
thanks man. im going to guess that is the problem is that o ring on the housing or something right there like said. the stock pump probably is ok just the o ring to hold the pressure failed. atleast it gives me a place to start.
the plastic housing crack can be pretty hard to see sometimes from the folks I talked to a while back, the crack can kind of seal itself back together when its not under pressure, so if it isn't the o-ring then check the housing carefully with a good light and fingernail or something - it can be like finding the end of a roll of tape good luck!
If you have a fuel pressure gauge hooked up to the car pinch off the return hose and see if it changes. If it doesnt . Look at the hose on top of the fuel pump inside the fuel tank.
