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There appears to be an issue with the fuel draining back when the vehicle sits overnight preventing a quick ignition in the morning. If the key is turned just to the on position for a few seconds, the car starts right up, otherwise you would have to crank it for a while. I assume the fuel is draing backwards in the line overnight. Is there an anti backup valve to prevent this, or is the fuel pump losing prime somehow?

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+1 to LT.  Check the engine bay, that's the most common area for leaks of non-rusty vehicles (yours is too new to have any rust related fuel line issues).  Fuel line comes in from the back/top drivers side of the engine bay under the drivers side windshield wiper so to speak, and snakes over to the engine.  look and smell for signs.  it's hard for gasoline to hide being so pungent.

 

Easiest next step I can think of is to pull the spark plugs, one at a time preferably, and see if any of them or their corresponding cylinders smell like gas.  This will tell you if gas is leaking past the injectors into the cylinders. 

 

In general the pressurized fuel system is bleeding off pressure over night which means fuel is leaking, and not just "back into the gas tank", it has to be:

1. back into the fuel tank

2. into the engine cylinders

3. externally. 

 

2 & 3 are really bad, but extremely rare on Subarus which typically have robust fuel systems. 

 

 

 

Check the engine bay area.  Fuel line comes in from the back/top drivers side of the engine bay under the drivers side windshield wiper so to speak, and snakes over to the engine.  look and smell for signs.  it's hard for gasoline to hide being so pungent.

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Your car has a returnless fuel system and therefore has the pressure regulator mounted in the pump assembly.

The regulator acts just like a one way check valve does on a non-returnless system at shutdown to keep the fuel rail pressurized.

All it takes is a small piece of grit to keep the valve from seating.

 

Leave a fuel pressure gauge on it overnight for confirmation.

Pinch a rubber part of the line closed to confirm whether the regulator or an injector is leaking.

(It will be the reg. IMO)

Usual fix is to replace the pump assy,but,I have heard of people adding a check valve.

 

It is worth having a look at the fuel lines in the engine compartment for any seepage w/running.

Gas leaks can be hard to smell in cold weather.

My own car developed a small leak there during our recent cold weather.

 

I have had all the failures GG mentioned and certainly do not agree that Subaru fuel systems are any more robust than any other make.

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Great, glad they finally made that move, it's always seemed silly to have a fuel return line snaking back the length of the car again!  Fewer rusty lines to repair in the future...though I generally avoid rust anyway, lol. 

 

How often do you see *subaru non-turbo* regulator failures - have you seen one this new? 

 

I've never seen a regulator failure even on gobs of miles 1980's Subaru's.  

 

 

 do not agree that Subaru fuel systems are any more robust than any other make.

 

I was mistaken by the movement of the regulator to the tank, but I never compared Subarus to any other makes. besides rust, occasional fuel pump, and a few platform specific issues - turbo's, 00-04 caps/orings, H6 intake hose tightening...etc), most 200,000 mile Subaru's have their original injectors and FPR's, so I caution people to jump to those right away. 

 

I've never seen one fail, all my 200,000+ mile Subaru's have original regulators, and there's no confirmed fuel pressure regulator failures on the first page of a google search I just did.  

Something not "robust" like headgaskets, aftermarket axles, wheel bearings, delayed engagement into drive, torque bind.... - and you're flooded with nearly unlimited reading. 

 

That's all I meant by "robust".

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Can he replace just the regulator part? probably not - they're all assemblies now right?

 

I'm not a big fan of aftermarket pumps so I'd look at repairing this one, getting a Subaru OEM unit (probably $$$), or even a used lower mileage Subaru pump. Seems weird to put a used pump in such a new car but I'm not at all convinced new aftermarket pumps are more reliable than a low mileage Subaru OEM used pump on something this new.

www.car-part.com

Edited by grossgary
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