Stalls on hard left turn from stop

[Bettlesr]

Hi!
I have a 2001 that I recently bought. It has no codes showing. It seems to run fine until I take off hard making a left turn from being stopped. Really a pain when I have to turn left in traffic. It only seems to do this below 3/8 of a tank of gas. I filled it right after I had this problem, It took 10 gallons and the problem went away. Anyone have any ideas what to look for? I would be nice if it ran until at least the low fuel light came on. Feels like it is out of gas. If I straighten out and let it coast or sit for a minute, it runs fine again.
Thanks

[1 Lucky Texan]

hmmmm, you symptom is not typical of a compromised cap/o-ring on the fuel pump. Might be worth inspecting it.

Also, i have read of a 'jet pump'/'venturi pump' device that is in our fuel tanks to push fuel from the left side to the right side for pump pick-up. But if that item was clogged, it would seem a RIGHT turn would cause a stall. Also, do you ever notice a vacuum or any whooshing when you remove the gas cap?

anyway, might be worth running a can of SeaFoam through a tank of fuel in case something is partially clogged.

[rasterman]

Doesn't the '01 have a fuel filter under the hood? maybe it's gunked up and you aren't getting enough fuel pressure overall.

[cardoc]

The fuel level sensor is on the pump side, so if its registering fuel at the gauge, the transfer pump is working to move the fuel. We can assume the level gauge works if 10 gallons fills it up and is not just a stopping point the OP uses.

Filling the tank up submerges the pump in fuel. There very well may be a leak in the pump assembly that is allowing for air to be sucked in at lower levels. Sharp left, fuel in the tank shifts away from the pump, pulls up air.

Pulling the pump takes about 10 minutes, after you've taken everything out of the way to fold the bench over. Look for a cracked hose at the base of the pump or a separated pump housing.

[plain OM]

The fuel level sensor is on the pump side, so if its registering fuel at the gauge, the transfer pump is working to move the fuel. We can assume the level gauge works if 10 gallons fills it up and is not just a stopping point the OP uses.

There could be a problem with the venturi transfer pump, although I've read about this happening only once in a Subaru. (A venturi transfer system is used in other makes as well.)

The fuel gauge indication is based on two tank sensors, one on each side of the car, wired in series. (See attached wiring diagram.)

The sub-sensor (on the left/driver side) has a resistance of around 62 Ohms, while the main sensor (mounted with the pump) is around 32 Ohms. Together, when both sides are empty, the total resistance is about 95 Ohms, and when full, around 5 Ohms.

If the transfer pump isn't working properly, using the example here, there could be a few gallons of fuel in the left side, while the right is near empty. The right side sensor, at near empty, would be at around 30 Ohms (I'm ball-parking), while the left side might also be around 30 Ohms. This would give a total of 60 Ohms which would put the gauge below half full, but not as low as 1/4, which corresponds to the "below 3/8 of a tank".

The right turn/left turn difference could be due to the location of the pump in the right tank and how fuel, at the bottom of that side, moves during these maneuvers.

I would be nice if it ran until at least the low fuel light came on. Feels like it is out of gas. If I straighten out and let it coast or sit for a minute, it runs fine again.

It should, but the low fuel light is turned on when the microprocessor in the instrument panel detects the total resistance above a certain point (probably in the 80-85 Ohm range). So, again, it's possible for the pump to be sitting in an empty area while there's still fuel in the other side, and the total resistance of the two sensors won't trigger the low fuel light. (This is only a suggestion as to what could happen.)

After the gauge gets down to 3/8 full and you experience the hard left turn stall, have you ever continued to drive (perhaps avoiding hard left turns) until the gauge gets down to 1/4, 1/8?

I'm not saying the venturi transfer system is the problem, but if the pump is going to be pulled as cardoc suggested, do so when the gauge is down around the 3/8 indication, and also pull the transfer pump pick-up and sub-level sensor unit on the left side to see if there's a lot more fuel in that side of the tank.

[1 Lucky Texan]

if he meant it held 10 gallons when measuring 3/8 tank, could be the transfer pump (didn't know what it was called)

I know the gauge isn't linear, but maybe he IS running out of fuel because some isn't getting moved over.

still, as you say, worth inspecting the fuel pump.

[CSFiend]

I had a very similar problem with my 94 Bonneville. Corners with less than a half tank of gas would cause the engine to stall until the fuel sloshed back. In my case, the strainer on the fuel pump was collapsed and wouldn't hold enough fuel to prevent stalling when the gas sloshed in corners. A new strainer fixed my issue.

I'll preface this by saying I've never been in an Outback fuel tank -- is it possible that the baffles in the tank have degraded?

[Bettlesr]

Thanks guys.
I will have to pull the pump and check that out. I had the fuel filter under the hood changed, did it before and did it after the change. By the way, what do I have to do to get at the pump?
Thanks again
Dick

[1 Lucky Texan]

here's some info and a video;

2000 Subaru Outback Fuel Pump Assy - YouTube

2000 Subaru Outback Fuel Pump Assy - YouTube

Symptoms of fuel pump O-ring problem?


Gen 2 H6 fuel pump O-ring failure- Ethanol?


let us know if you spot anything

[Bettlesr]

Thanks for the video, I'll remove the pump and check it out. I assume the other fuel level sensor is on the left side similar to the pump on the right? But, Wouldn't making a hard left turn cause the fuel to slosh over the the right hand side where the fuel pump is?