LUVTruck.com

I know this isn't a Mazda support site, but I really don't know anyone who can figure this out so I though I would try you guys.

My wifes car runs great, until it gets down around a quarter of a tank. I know the gauge isn't off, but when it gets to a quarter tank it starts cutting out really bad in first and second gear. When you take off the gas cap, there's alot of pressure that blows out of the tank like compressed air. It has a brand new fuel pump also...

Anyone know what could be causing this problem?

Any help would be appreciated, can't afford to take it to the shop.

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Richard Barnes Salt Lake, Utah
1980 Luv Mikado 4X4
http://geocities.com/luvtruck2004/

there could be water in the fuel tank, its happened to me b4, the water sits on the top and when the petrol runs down the water gets sucked through too, my suggestion would be to drain the tank and refil it maybe even put a bit of metho in there too to disperse the water a bit

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I said no to drugs....But they just wouldn't listen!

No matter how good she looks, some other guy is sick and tired of putting up with her crap!

gas floats on top of water... the water will always be on bottom

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if you aint skeered just a little bit THEN YOU AINT GOING AS FAST AS YOU SHOULD BE!!!!

GOTTA GET A NEW LUV!!!!!!!!!

are u sure? i could of sworn it wa sthe other way around

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I said no to drugs....But they just wouldn't listen!

No matter how good she looks, some other guy is sick and tired of putting up with her crap!

This is correct. Gas is lighter.

BANG there goes my theory, ya gota admit it did sound like a solution..rite

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I said no to drugs....But they just wouldn't listen!

No matter how good she looks, some other guy is sick and tired of putting up with her crap!

Does anyone know what all the components are in the fuel system on this piece of crap that could be causing it to over-pressure and cut out on me like this?

It was a beautiful theory noyz, damn chemistry though, always has to be right.

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Richard Barnes Salt Lake, Utah
1980 Luv Mikado 4X4
http://geocities.com/luvtruck2004/

It's a long shot but here's an idea. There might be a hole in the pick up tube in the tank. Once the fuel level gets below the hole (at a 1/4 tank), it will try and suck air in to the line. Aircraft can have this problem and it's usually an o-ring thats gone bad. Car fuel tanks aren't known to have o-rings in the fuel pick up tubes but maybe a sweged piece of line is involved.
As for the pressure in the tank when you remove the cap, that's normal (emissions crap).

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Previous setup: 4.1 Buick V-6/TH 350
Current setup: 400 Small Block Chevy V-8/TH 350
9" ford rear end/short bed/blue
What do Water, Electricity and Humans have in common... They all travel the path of least resistance.

The air might be rushing in to fill the vaccum that is created when gas is used and the tank is not vented.
Water may still be part of the problem. Many makers of gas tanks place a drain plug in the bottom of the tank to drain water and sedament (rust, dirt, etc.), out the bottom of the tank.
Good luk.

Can't be a pickup tube for the pump, cause the pump goes in the tank and sits right at the bottom. I bought a fuel injection techbook, and reading it I'm starting to think it's the fuel injector pressure regulator. I think when I step on the gas the vacuum opens up the diaphram, and lets the gas flow back to the tank, cause a loss of pressure in the rail. I just don't know how to connect that to the fact that it only happens at a quarter tank. I'm gonna put a new vented gas cap on it, just for shits and giggles and see if that helps.

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Richard Barnes Salt Lake, Utah
1980 Luv Mikado 4X4
http://geocities.com/luvtruck2004/

I went to drain the tank to see how it looked inside and when I crawled up underneath I was shocked to see that the center of the tank, right where the pump sits looks like someone picked it up and dropped the center of the tank right on a brick. So I'm either gonna get a board and try to dent it out from the inside where the pump goes in under the back seat or find a cheap one at a junk yard and just replace it.

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Richard Barnes Salt Lake, Utah
1980 Luv Mikado 4X4
http://geocities.com/luvtruck2004/

That would be a good place to start... your dent may be just enough to put the pump out of the gas under full throttle and low on gas ..

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if you aint skeered just a little bit THEN YOU AINT GOING AS FAST AS YOU SHOULD BE!!!!

GOTTA GET A NEW LUV!!!!!!!!!