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what are these two bumps?
Posted: Wed Jan 09, 2008 2:02 am
by slowjoe
i have a N/A FWD wagon and when i took out the trunk carpet, i saw these two round bumps that look like they cover something. they are held on by gold phillips screws. and they are in front of the spare tire wheel well. they also have some black foam sticking out the side. anyone know what these are or if its safe to open it up and check it out?

Posted: Wed Jan 09, 2008 2:45 am
by evolutionmovement
The right hand one is the fuel pump access hole. The left isn't used on fwds. The gas tank is underneath.
Posted: Wed Jan 09, 2008 7:26 am
by slowjoe
oh kool thanks!
Posted: Wed Jan 09, 2008 11:33 pm
by smh0101
Out of curiousity... what is the other one used for on an AWD?
You said it wasnt used on FWDs...
Posted: Thu Jan 10, 2008 12:20 am
by vrg3
AWD fuel tanks have a hump in the middle to clear the rear drivetrain, which means that when the tank is not very full it actually behaves kind of like two separate tanks. So, on the driver's side, there's a Bernoulli pump that moves fuel to the passenger side (where the main fuel pump is), and also a separate level sender. These are accessed via that second bump.
Posted: Thu Jan 10, 2008 12:27 am
by smh0101
Just reading vrg3's convoluted, information-packed posts made me feel better all over again.
lol... jk
Thanks Vikash... Very interesting... Why does subaru always have to complicate things
I dont know if this was a problem with my old car or what... but are when I would get to about a 1/4 tank the light would come on... then go off and come back on at almost the "E" level...
Could that have some thing to do with the separate tank thing?
Posted: Thu Jan 10, 2008 12:32 am
by vrg3
It's not really that complicated though... How else would they have done it?
I don't think that your problem had to do with the secondary level sender, except for the fact that there are two senders to go bad instead of just one.
Posted: Thu Jan 10, 2008 12:34 am
by smh0101
Well it isnt that complicated, just an interestin thought...
Anyways...
So if the car was tilted one way... would one read a lot more than the other one? and give you an innaccurate reading?
Posted: Thu Jan 10, 2008 12:53 am
by vrg3
Yes, one would read a lot more than the other one, but the gauge needle would give you a good reading. That's the point of the dual-sender system; the gauge indicates the average of the two levels.
Posted: Thu Jan 10, 2008 12:56 am
by smh0101
Oh... Duh... Brain Fart...
Thanks Vikash, I didnt know about the split tank and dual sender thing... Very Interesting!
[/End High-Jack]