Subaru Outback Forums banner
  • Hey everyone! Enter your ride HERE to be a part of this month's Ride of the Month Challenge!

1 - 20 of 27 Posts

·
Registered
Joined
·
185 Posts
Discussion Starter #1
Fuel Pump running with car off.

Tonight I came home late and heard something running in my attached garage when I walked in. It sounded lie a sawzall was being used somewhere. I knew it wasn't a neighbor as there isn't one in 1000'.

I put my head near the left rear corned and it sounded like a someone was using a vibrating sander ( No Jokes Guys) in the rear quarter. The only thing I can think of is the fuel pump. I retrieved the key and started it and turned it off and the sound went away.

What do you think it was?
 

·
Registered
'14 3.6R Outback
Joined
·
2,345 Posts
I think there is also a pump for the fuel system that is active after the car is shutdown, several minutes after in fact. I think I remember reading about it in the manual and on this forum.

Edit: not what I was thinking but it describes the fuel system better than I could:
http://drive2.subaru.com/Sum03_FuelSystem.htm
 

·
Registered
Joined
·
185 Posts
Discussion Starter #4

·
Registered
2019 Forester Sport. Love the Orange.
Joined
·
4,018 Posts

·
Registered
Joined
·
22,802 Posts
All cars have this - rarely if ever is an issue simple device. But it can sure make people scratch their head walking into the garage and hear something on their car running long after the car was driven.
 

·
Registered
Joined
·
15 Posts
...we noticed the same sound last evening. Sounded like a very 'small' fuel pump, just inside the left rear wheel well. We just picked up a 2013 Outback, and I also thought it was the fuel pump still on. Been several hours since the car was last running. We cycled the ignition, and that's when I heard the fuel pump (much louder, and only for a brief moment until pressure built up then it cycled off on its own), and the other noise had stopped.

Called the dealership this morning, they echoed a 'fuel tank vent control' thing - didn't know for absolute certain but at least they knew of something in that vicinity that made noise when the car is off.

So good, looks like 'it' is functioning normally.

Great info in this forum :29:

And I feel obligated to say we reeeeally like our new Scooby :)

- Sam
 

·
Premium Member
2005 3.0 R n totaled
Joined
·
7,526 Posts

·
Registered
Joined
·
18,722 Posts
Do you know which fuse controls this feature? Not that I plan to remove it but I don't want to add-a-circuit to that fuse spot, if it keeps running after the car shuts off...
There might not be a specific fuse for this particular function; instead, the power for it could be from the ECM or BIU which have an "always on" supply, and would turn the test on at the specified time.

I don't have a 2013 FSM, but would imagine the device (whatever it's called) can be found on the wiring diagrams and traced back, in the event there is a unique supply.
 

·
Registered
2013 Outback 2.5i Limited /Eyesight
Joined
·
4 Posts
Funny, my 2013 Outback did the same thing last evening. I went in the garage to get something and I heard a noise like a quiet buzzing sound. I finally isolated the sound as coming from the rear of the Outback. It must be the fuel pump. My guess is that the fuel pump runs at engine shut down to keep the fuel line primed. And in this case the pressure activated on/off switch did not function correctly. As soon as I started the Subie and shut it off the pump noise stopped....

I wonder if the battery would have discharged had I not gone into the garage at 10:30 PM... It must have been running for 4 hours...

I was happy to see your post... I thought that I had experienced a one of a kind gremlin.
 

·
Registered
2013 Outback 2.5i Premium 6MT
Joined
·
34 Posts
I wonder if the battery would have discharged had I not gone into the garage at 10:30 PM... It must have been running for 4 hours...
It wasn't going for four hours, it happens after the car has been sitting for 3-4 hours and only lasts a few minutes. Your battery would have been just fine had you left it alone.
 

·
Registered
2016 Outback 2.5i Premium w/nav/eye
Joined
·
366 Posts

·
Registered
2013 outback 3.6R
Joined
·
1 Posts
Happened with my 2013 Outback this week. I, too, was very concerned about battery drawdown. I had no idea how long it ran with the engine off.
 

·
Registered
2010 Chevy Traverse, 2012 Subaru Impreza, 2015 OB 2.5L Red/Nav/sunroof/eyesight/BSD/keyless/remote start
Joined
·
18 Posts
Happened to me tonight. Went out to the garage 4 hours after using the car. Heard a buzzing noise and finally traced it to the outback.

Good thing the OB forum exists - issue resolved and my concerns alleviated - otherwise I'd be calling the dealer.
 

·
Registered
2014 2.5i Limited
Joined
·
950 Posts
I wonder how frequent this is happening. Is it after every drive? Once a month?
 

·
Registered
2013 Outback 3.6R Limited
Joined
·
500 Posts
Technology have evolved. I, like many, grew up with the clear understanding that one's car was off until we sat in the driver's seat, inserted our key and turned it on. When we removed the key that sucker was off and out cold. Not now. We need to understand that our vehicles are operational 24/7. I am reminded of this, when I approach my OB at night and the puddle lights (cool option) illuminate before I can grab the door handle! The vehicle is at the ready and looking for my fob signal. I love that push button start. I almost forget that I have the fob/key in my pocket. Now that I have experienced two vehicles with push-button start and actually a third since my GF has a 2012 Prius., I would never want to go back to the stick-the-key-in and turn thing.

Corvettes are worse with this constantly "on" mode. The newer model Corvette owners all understand that their vettes cannot sit stored in the garage for a month or so without the battery being drained. There is so much activity going on with the car parked in the garage. Batteries don't last long in vettes because of this and the storage thing. In fact, GM recognizes this to the point that a battery tender is a regular option. My 2012 vette came with the optional vette logoed tender and I use it all the time.
 

·
Premium Member
2005 3.0 R n totaled
Joined
·
7,526 Posts
Fuel pump has several hoses coming in and out. One of them is a return hose; some of the features (since fuel system operates under pressure) is that fuel pressure is lowered automatically, after the car is turned off. Even if and when you are replacing a fuel pump, first thing you have to do is relief the fuel pressure from the system before you start removing the hoses. There is a step-by-step procedure in Subaru's repair manual, how to do that.
 

·
Registered
2016 Outback 3.6R Wilderness Green
Joined
·
10 Posts
Tonight I was servicing the carb on my Tiller in the garage, when I heard a electric motor noise coming from the Outback. Upon closer inspection I noticed the noise was coming from near the rear wheel-well on the driver side. (around the fuel tank)

I am assuming it was the fuel pump, not sure. The key FOB was inside the house so there was no way the the ignition was on. The only way I got the motor noise to stop was starting the car and turning it off.

Could this be the reason on the 2016 outbacks the battery died pre-maturely? Its just a theory, I will keep a watch on this weird problem.
 
1 - 20 of 27 Posts
Top