99rx

iTrader: (6)

I have noticed since my grandfather got the car in 2000 (and always complained about the pumping issue), then gave it to me, that I am unable to pump the gas at full speed or else I get a large air bubble, I'm assuming, and the pump keeps stopping. And I also notice that no matter how full I get the tank, after 15-20 miles my gauge looks like this:

Can anybody else help me confirm that this is somewhat normal? Do you have to pump gas slow as well. I mean I normally pump it half way anyways (because of something I read about pumping slower allows the gases to escape easier), but the last time I filled it, I pumped it so slow that 2 people came and went filling their tanks. I did this to see how full I could get it to see what happens to the gauge. But normally I pump it at half speed and the gauge reads the same after roughly 15-20 miles. This picture just happens to be after 15.2 miles.
Thanks in advance for any advice.

salimshah

We have had discussion on slow filling on some RX.

My diagnosis was blocked breather tube.

Lexus gas gauges are fairly linear at the top end. Typically American cars are inverse exponential (gauge moves rapidly at the low side and hardly move near the full.

Salim

99rx

iTrader: (6)

Yeah I've read through a lot of those discussions, but I thought this issue was different. I'm curious to see if everyone else gauge moves like that. And how does one go about unblocking this breather tube?

dbui

Ok I don't have this problem on my RX300 knock on Wood! but on my 2001 Benz clk430 the fuel sensor mess up some how and I have to replace it. Every time I gas up, it takes me at least about 10-15mins to pump the gas, the gas handle keeps stopping 2-4sec and it very annoy. I don't know RX300 have this fuel sensor or not?

Lexmex

Run some fuel injector cleaner in the gas tank, and also remove the battery cables for about a minute and then put them back on to reset everything.

salimshah

There are three possible issues, so please clarify.

1. Gas filling issue: You need to do a slow fill]. Simple physics in action ... The air inside the tank needs to be dispelled ...[breather tube]. Disassemble filler neck/drop tank/? Maybe someone will share how they did it. I have not.

2. Fuel gauge shows incorrect fuel level. Sensor, wiring, ecu, display. [Reset ecu to start with as Lexmex suggests]

3. Peculiar fuel gauge response. [That is the way the RX works or reset ECU]

Salim

jbl-1985

The only way I get around that is to stand at the pump for about 10 minutes and top it off for that amount of time. The first time the pump shuts off in these cars, they aren't nearly full.

99rx

iTrader: (6)

1. In the OP, I said that I fill it everytime at half speed. This past time I filled it slower than that just to see if it would change how much gas went in, and to see if the needle movement differed after the 15-20 miles of driving, as opposed to the other times I've filled it.
2. I shall try this.
3. We shall see after I reset it eventually.

mckellyb

I've found, if you fill the tank to the top, something happens to the vent tube, and you'll have slow fills for a good while.

Try running around with no more than 5/8 of a tank for a month. It helped my wife's car after it spent a few years in storage.

hypervish

I've only had the issue of not being able to pump gas into the tank at a normal rate when on a road trip and come upon a bad gas station whose pump is not working properly. At that point I either go to another gas station, or move to a different pump.

salimshah

Hyper pointed out another possibility about the pump nozzle/sensor being bad.

If the vent pipe has no links there is another possibility ...
The breather tube is a path for the air/vapors to escape during filling and can have dust accumulated in it (years). When someone overfills, the gas runs down the air vent pipe. That can push the dust down and eventually clog the pipe.

Salim

BIGASSL

no one seems to have an answer. on a camry it's a blocked charcoal filter. whats blocked on lx470 thats causing that same problem?