TC gas light comes on very early..question for mpg squeezers

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08-27-2005, 05:49 AM

#21

ILLCRXSI

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Quote:

Originally Posted by ravidavi

Quote:

Originally Posted by PonyTc

it scares me to let it even get that low... isnt it bad for your car?

Gather 'round kids, Explanation Time!

Cars have gas tanks, cars have engines. To get gas from the gas tank to the engine, a car has a fuel pump. A fuel pump, like any other pump, gets hot when it's working. So to cool off the fuel pump, carmakers put the fuel pump in the gas tank...it's submerged in liquid (gasoline to be exact), which cools it off.

Now suppose you chronically run your tank dry. If there's not enough gas in the tank to cover up the fuel pump, then the pump heat up. Now it won't get so hot that it'll catch on fire or anything catastrophic like that, but over time letting the fuel pump get hot over and over can shorten it's lifetime.

All this means is that, no it's not bad for your *whole car* to run your tank dry continuously, but why be mean to your fuel pump unless you're a poor high school student whose parents would buy you a brand new $17k car but won't give you the money to buy gas for it?

Ravi

absolutely correct and in reply to the earlier post, a low gas tank will in no way cause a lean condition. in fact only running the tank down to 3/4 before refilling is probobly worse for the car than running it down to empty with forced induction. a bunch of old gas in the tank might actually cause detonation, while driving with 1/4 tank will in no way shape or form affect the a/f ration.

08-27-2005, 06:34 AM

#22

all4degame

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one day your guys are gunna find yourself putt putting your tc into the gas station on FUMES..

08-27-2005, 06:52 AM

#23

barefootbilly

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bah, i do that all the time. As of right now, I can't rev past 4k without it sputtering and dying. I really should go get gas I guess.

I drive to work and back home all the time (25mile round trip) when the lights on. I just go until the gas sputters. That's a weird feeling.

08-27-2005, 07:04 AM

#24

ravidavi

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Quote:

Originally Posted by ILLCRXSI

Correct on the statement about running lean...the tC, like other modern cars, is fully computer controlled. The amount of air coming into the engine and amount of fuel being sprayed by the injectors is very closely monitored and controlled.

However, let's apply some reasoning to the statement about 'old gas'. Gasoline stored in a modern automobile gas tank does not begin deteriorate (what you call being 'old') for at LEAST a month, usually 2-3 months or longer if the car is active. Even if you topped off gas once a week, at the 3/4 level each time, after two months only about 10% of the original gas would remain. And that's a conservative estimate.

Basically, the moral is that as long as you're not running your tank to empty every single fillup, you're not doing any damage to your fuel pump, much less to the rest of your car.

Ravi

08-27-2005, 04:48 PM

#25

ILLCRXSI

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wasn't stating that only running your car down 3/4 of a tank was bad, just stating that running it down to only 3/4 of a tank all of the time may actually have a slight risk(even though it probably is impossible and won't happen). but driving your car with any amount of gas in the tank won't affect a/f ration, sorry if i wasn't clear before.

08-28-2005, 04:24 PM

#26

Dyltone

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I must have a very very heavy foot (hehe)! I usually have to fill up between 240 and 260 miles per tank and I run that _____ way past the R line (for some reason everyone here has an E?). After my low fuel light comes on, I usually go about 40 to 50 miles before filling up. The most mileage I've ever gotten was on a highway trip and it was a little over 315 miles for the whole tank.

08-30-2005, 01:51 PM

#27

Dat_Dude

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Quote:

Originally Posted by barefootbilly

that is just stupid... you should not to allow your car to operate in that condition. Those sputters are actually misfires b/c the lack of fuel. Misfires can cause premature wear and damage.