Resolved: When low on gas...

jfjohn · 08-31-2010, 05:42 PM

I have a 96 taurus gl. It seems like when the tank is low on gas, the engine runs a bit leaner and maybe I'm even getter better gas mileage at the bottom of the tank. Maybe because the car is lighter with less fuel but could it be that the computer is running the car leaner because it knows I'm going to run out of gas so it's trying to conserve fuel by running leaner?

Poppy · 08-31-2010, 06:16 PM

Wanna buy a bridge?

G O R T · 09-01-2010, 03:56 AM

The gas gage sending unit is getting old.

RollinWOT · 09-02-2010, 07:38 PM

as GORT said the sending gauge could be getting old, but newer cars, when they're low on gas they go into limp mode so you cant get to WOT and waste all your gas, so the CPU is probably equipped with a basic air:fuel ratio monitor or rudimentary limp-mode-ish program, so check into the gas guage sending unit, and check the computer with an OBDII scanner, because sometimes the limp-mode problems dont set off a warning light when your just close to running out of gas. Hope this helps
-RollinWOT

Poppy · 09-03-2010, 05:01 AM

Originally Posted by RollinWOT

, but newer cars, when they're low on gas they go into limp mode so you cant get to WOT and waste all your gas, -RollinWOT

I never heard of this. Certainly this is not true in 1996!
What year did this start? Can you name a couple of vehicles that have this feature?

Poppy · 09-03-2010, 05:09 AM

john,
you shouldn't run it so low on fuel, I've been told that when if the fuel level is so low that it sloshes around in the tank, that if the pump momentarily runs without fuel, that it will lead to premature wear of the pump.

Secondly unless you ran it hooked up to a meter, you have no idea if it is running leaner. And if it is running leaner it is less than optimal.

Thirdly, unless you have a way to actually measure the amount of fuel that you burned, so that you can divide that into the number of miles that you drove, then you have no method of calculating your gas mileage.

Might you actually get a little better mileage with 1/4 tank than a FULL tank, yeah because of the reduced weight. Would you notice the difference? Absolutely not. You're only talking about 120-150 lbs.

Lip Ripper · 09-03-2010, 10:25 AM

"Limp-mode-ish"? Is that a rap song? Limp-mo-dat.

Jonzo77 · 09-03-2010, 02:24 PM

Originally Posted by Lip Ripper

"Limp-mode-ish"? Is that a rap song? Limp-mo-dat.

kinda sounds like E.D.

RollinWOT · 09-03-2010, 03:04 PM

poppy, i hear where your coming from, and im saying on newer cars, and i mean around 08 and newer, but beyond that im at a loss. i was also very tired when i wrote that, having being up for almost 2 days straight, so as you can image, i was acting very eccentric

Dominick · 09-03-2010, 03:54 PM

I did some reading on it and the limp mode in the Taurus was transaxle related when you had an erratic shift pattern.
Other Ford products were ECU related when the trans was acting up in a shft pattern it tell the ECU to go into that mode.
2008 Mustang showed it fuel related as well as the F-series diesel trucks.

jfjohn · 09-03-2010, 03:58 PM

Originally Posted by Poppy

john,
you shouldn't run it so low on fuel, I've been told that when if the fuel level is so low that it sloshes around in the tank, that if the pump momentarily runs without fuel, that it will lead to premature wear of the pump.

Secondly unless you ran it hooked up to a meter, you have no idea if it is running leaner. And if it is running leaner it is less than optimal.

Thirdly, unless you have a way to actually measure the amount of fuel that you burned, so that you can divide that into the number of miles that you drove, then you have no method of calculating your gas mileage.

Might you actually get a little better mileage with 1/4 tank than a FULL tank, yeah because of the reduced weight. Would you notice the difference? Absolutely not. You're only talking about 120-150 lbs.

Believe me, I never like to let it even get down to a quarter tank but I've been so broke lately that I haven't been able to always buy gas when I need it.

EscortTard · 09-03-2010, 09:39 PM

Originally Posted by jfjohn

Believe me, I never like to let it even get down to a quarter tank but I've been so broke lately that I haven't been able to always buy gas when I need it.

You'll be even broken when you have to shell out $300 for a new fuel pump.

The pump is submerged in the fuel, and the fuel actually helps to dissipate the heat that the fuel pump generates... a coolant of sorts.

When you constantly run it down below 1/4 of a tank, there is less fuel available to dissipate that heat, and the increased heat can reduce the life of the pump.. or even kill a worn pump.

Just remember... aside from an initial investment... it costs the same to keep a tank full than to keep it empty...

Poppy · 09-04-2010, 08:31 PM

jfjohn,
I'll pray that your finances get better.

I think that the rest of your post has been explained away.

jfjohn · 09-06-2010, 09:31 AM

Originally Posted by Poppy

jfjohn,
I'll pray that your finances get better.

I think that the rest of your post has been explained away.

Thanks, Poppy!

mark v · 09-07-2010, 12:47 PM

I 100% agree with Poppy's post #6.

jfjohn · 09-29-2010, 06:19 PM

I was thinking that when the tank is low, maybe the gas becomes aerated from the increased sloshing around in there. Maybe that makes it burn leaner and increase mileage.

mark v · 09-30-2010, 07:57 AM

Nope this does not happen, even if it did when the fuel gets under pressure the air would be removed.

Leaner also makes detonation and that creates pinging which results in engine damage.

Originally Posted by jfjohn

I was thinking that when the tank is low, maybe the gas becomes aerated from the increased sloshing around in there. Maybe that makes it burn leaner and increase mileage.