Mazda recommends >1/4 tank always full?
 

Howdy all,
My manual says Mazda recommends to always keep the fuel tank over a quarter full and to refill immediately once the light comes on. Is this to avoid calls to Mazda's roadside assistance, or is there some engineering reason to keep the fuel tank over 1/4 full (pressure issues, vapors, condensation building in the tanketc..).
Just curious. :) :)
Josh

Its not going to hurt anything to run with less than a 1/4 of a tank. It is going to do a little damage to run out of gas, engines really don't like that. Anyway just do what the manual says and err on the side of caution.

When I took delivery of my Protege the dealer suggested refuelling at 1/4 tank to keep the fuel pump submerged.

"The fuel keeps the pump cool - if it runs too hot it shortens it's service life."

So... I always refuel at a 1/4 tank. Besides, a "fill-up" seems cheaper then (even if it is more often) :)

I think the reason for this is that it is bad to run out of gas and let your electric fuel pump overheat. The pump needs to have gas flowing to help keep it within reasonable operating temps internally. You can burn it out pretty quickly if it's only pumping air.

Jeff M.

One reason could also be that cat can get really hurt if U run out of gas, or actually it's the restart after running out of gas that can hurt cat. So to make sure this doesn't happen they recomment to keep enough fuel in the tank

On my old 323 (after surpassing 100K miles) it was more difficult starting my car up the first key turn during the day when near empty fuel tank. It would have no problems cranking up immediately first thing in the morning when the fuel tank was full.

i've heard if the tank is too low, the injectors can be clog from picking up the crap normally flowing around the bottom of the tank.

Yes, you do tend to get sediment in the bottom of your tank, and the less fuel you have in your tank, the less diluted that sediment becomes.

Also, if you are running low on gas and you hit a hill, sometime the gas will slosh back in the tank somewhere away from the pump. This happened in my old Toyota once. I knew I had a good 15-30 miles left in the tank, and there was a gas station 3 miles away, so I wasn't worried. I started going down a hill and the engine started to sputter out. Luckily, I was going down hill, so I coasted to the bottom, then popped the clutch and I was good till the gas station. Close call though... so when the light goes on, start looking for a place to fill.

Like a few people have already said, Mazda recommends that so you don't clog up the injectors or burn out your fuel pump from sediment in the tank.

One thing
 

You should replace the fuel filter offend.
This will help alot.
IMO:beer:

A fuel tank has a baffle in it, it looks like a plastic bowl around the pump. When you have less than a quarter of a tank, the fuel dosen't flow into the baffle as well, the sides are too tall. If you keep the fuel level higher than the baffle, the pump's draw tube will always be in fuel, because the baffle is always full of fuel.

I notice in my car when bellow 1/4 tank, after stopping at a stop sign, then pulling away (slightly above normal driving style :D ) when I shift into second I get a dead spot like the engine isn't getting any fuel for a second or two. I couldn't figure what the problem was, I filled the tank and the problem disappeared.

I am assuming the problem is because of the above mentioned baffle... and it couldn't be my fuel filter needing a change, my car ran a 16.533 in the quarter last weekend :cool: !

on the fuel pump subject...
 

I've heard the RX-7 fuel pump will interchange with the Protege's pump (assuming the electric pump, not the tubes and top plate) Can anyone confirm this? There are high volume fuel pumps for the RX-7 available.

Thanks all! Great info.
:)
Josh

also in colder weather if you have less gas in your tank there is the chance of condensation and this will freeze your gas line.. not good.. but Gas line antifreeze will fix this
________
Toyota Fortuner Specifications

You won't clog injectors from running the car out of gas. That's an old myth. Where do you think the fuel pump pickup is in the first place? At the bottom of the tank. If sediment is in there, it's getting sucked up all the time.