2007 Ford 500 Fuel Tank Design

[FMC]

I have been tinkering with fuel adds for about the last six months, I have used MMO, TCW3, Redline SI-1 individually and in combination, for example, 4oz MMO + 2oz TCW3 per tank (20 gal) or 5oz SI-1 + 2oz TCW3 per tank (20 gal) but I sometimes experience different results with the combinations, but one thing I seem to notice is when i'm at 1/4 tank or less my performance drops off slightly, my acceleration seems to go flat, I have to drive thru it and really get the RPM's up, after a refueling and with about .4 gal used the performance comes back to normal, if I do not use any adds in the refueling, this does not occur.

It seems the tank design is what's called a saddle type with left and right chambers with a transfere line from one side of the tank to the other, i'm guessing that when i'm dumping the fuel adds into the almost empty tank it's not being evenly distributed between both sides of the tank and remains more concentrated on one side.


This is from the service manual

- a dual-container (saddle-type) high density polyethelene fuel tank.

- a fuel level sensor in the left fuel tank half to transfer fuel from the left to the right, which contains the fuel pump module that supplies fuel under pressure to the fuel rail.

- a fuel tank filler pipe which contains a restrictor plate to permit only unleaded fuel to be pumped into the fuel tank.
-
- a fuel tank filler pipe assembly that cannot be modified in any way. The fuel tank filler pipe is serviced only by installing a new filler pipe assembly.

- a 1/4 turn fuel tank filler cap.

- an electronic returnless fuel system.

- a fuel filter that is mounted in front of the fuel tank on the right hand side of the vehicle providing filtration to protect the fuel injectors.

 

[eljefino]

So when are you dumping the adds? At the station, just before you pump?

It should mix in a full tank just from sloshing around.

You might want to check your fuel pressure or your o2 sensor block learn (or whatever they call it) in case you're simply running lean from a failing pump, clogged filter, etc.

 

[FMC]

Originally Posted By: eljefino
So when are you dumping the adds? At the station, just before you pump?

It should mix in a full tank just from sloshing around.

You might want to check your fuel pressure or your o2 sensor block learn (or whatever they call it) in case you're simply running lean from a failing pump, clogged filter, etc.



I drive until i'm on empty, with the DTE readout on the dash at 0, this will allow 18.5 - 19 gallons to fill with pump clicking off, and yes I put the adds in first them pump.

I have a Innova scanner that reads live data, the fuel pressure is good @ 40 psi, the 02 sensors are switching, fuel filter was replaced as routine maint, 5000 miles ago.

It's really very odd, the way the tank is made, when filling, the right side will reach full and spill over the center of the tank into the left side, but i'm not sure how the pick up tubes or cross over tube works. Does the fuel pump receive fuel from both sides at the same time ?