rfx45

I've searched and did not really find any information I was looking for.

I own an IS250 with an Auto tranny and tonight my dash read that I have approximately 15 miles left in my gas tank and the "warning light" has been on ever since it hit that there were 30 miles left. I assumed that I have about 3/4-1 gallon of gas left so I filled the 250 up. It filled up to full capacity which added about 14.5 gallons of gas.

I didn't try to top off the tank when it stopped pumping but the dash showed that it is at full capacity. Having 1 gallon of gas left plus the 14.5 gallons I filled it up with, only equals to 15.5 gallon of gas while the IS250 is suppose to have 17.1 gallons. Is this pretty normal? Has anyone experienced anything like this? I've only had this car for less than two weeks and just hit the 550 mile mark this morning. Can it be from the break-in period or is this pretty typical for the IS250?

Sorry for the long read and thanks for any help.

al503

I've found that there is about 2 gallons left when the computer says zero miles to empty.

rfx45

^^^ Is it done on purpose? Because even the gas tank needle goes to "E" as well. Did Lexus make it like that as a safety feature so people won't risk running out of gas? 2 gallons seems a lot of gas to be considered as a "reserve". I think the light and computer/dash showing how many miles left is enough but who knows.

lobuxracer

iTrader: (2)

Probably on purpose. Mine is the same.

rfx45

I see. Thanks for the help guys. I guess I can afford to go below "0" on what the computer says.

sirkfc

i wouldn't risk going too far under 0. note that the miles remaining number never goes up, no matter how you change your speed or patterns... so i think theoretically, if you were driving at one constant speed for an entire tank, 0 would mean 0. otherwise, there's a little slack.

IS250SoCal

^^^Very good point^^^

Please also refrain the use of BIG words, ex. "theoretically" JK

Kurtz

iTrader: (1)

It's always a bad idea to drive that low- Most fuel pumps in modern cars are cooled by the fuel in the tank... driving under 1/4 tank often shortens the life of the fuel pump as a result

al503

I doubt that you would hurt anything going past a quarter of a tank left. You can't expect people to be refilling every 12-13 gallons used.

Bichon

Agreed. I don't even think about filling my tank until the warning light comes on; I've been doing so since electric fuel pumps were introduced in the late '70s, and haven't had a fuel pump problem yet. Other people have said not to let the tank run down because you'll pick up junk at the bottom of the tank, but examining my fuel filters after changing them leads me to think this is an urban legend too. (BTW, I've never ran out of gas, though I may have come close a couple times )

lobuxracer

iTrader: (2)

The only engine you never run out of fuel is a high pressure diesel. Purging the air from those it a major PITA. No gasoline engine needs to worry about fuel pump damage from overheating, especially a Toyota where they have used a multispeed approach to solving the fuel heating issues caused by recirculating fuel systems.

Returnless systems are even less likely to have issues, but our GDI does have some return built into it, just not on the low pressure side.

Kurtz

iTrader: (1)

http://www.popularmechanics.com/how_...36.html?page=2

"Never attempt to bench test a new or old pump. In-tank pumps use fuel for cooling and lubrication. Running one while dry will quickly damage it"

You guys keep running your tanks dry... given it's a Lexus you probably won't have problems for a while. I'll keep stopping for gas at 1/4 tank and not worry about it.

lobuxracer

iTrader: (2)

Bench testing dry and running dry in tank from running out of fuel are two different worlds.

socalJD

^^^ Hmmm, a newbie with less than 40 posts takes on 2 moderators and another senior member with well over 1,500 posts. I wonder who most posters will believe . . .

Kurtz

iTrader: (1)

*shrug* last 2 lexuses I've been in went over 250k miles, and my last daily driver had over 500 hp... I know a little about mechanical stuff.

The guys from Car Talk say the same thing about not running the fuel pump on an near-empty tank, as does a slew of other pretty reliable sources.

I'm sure the moderators here are smart folks, but it's not like I got this advice from a cracker jack box.