Gas Gauge Malfunction

[Bum-bling-B]

This tank is doing the same thing. At 48 miles my first bar went down. I'm going to run the tank past 340 and once I refill we'll see how the next tank goes. I burn through the tanks pretty quick so we'll see what happens next.

Hopefully nothing major as the sending unit is wrong with it. Does it go into the top of the tank? Would that mean pulling the seats? I really want to get a tech manual for this thing as I'll be out of warranty in a few months anyhow.

[daleharrison]

Originally Posted by SmarTek-TNG

I have not had any Smarts with exactly the symptoms you describe, but I can say I have replaced 4 or 5 fuel tank sending units for gas gauge related problems, over the past few months. (I am the smart tech at Germantown, MD). Generally, the cars will come in with a problem like, "my gas gauge is stuck at 3/4 and never goes down even though I have driven 200 miles". Usually I find a fuel gauge sending unit fault code, and replacing the sending unit fixes it. Sometimes just resetting the instrument cluster with the Smart laptop fixes it, but I question whether this is a band-aid that doesn't really address the root problem, so I replace the tank sending unit anyway.

hope this helps

SmarTek-Thanks for the reply. I e-mailed my salesperson about the problem and he suggested I be very careful to fill the tank next time and monitor the gauge. If problem reoccurs then I will get in touch with Service Dept in Cary,NC. Otherwise, Smartie is doing fine. Again thanks.

[SmarTek-TNG]

The tank has to be removed (or at least lowered.. you can get away with leaving the hoses and vent tubes connected as they have a lot of play) from underneath the car to replace the sending unit. A lift would be very very helpful, and I personally wouldn't want to do this without one. With a lift, it's actually not a very difficult job, although you do have to drain the tank first, and for this the easiest way I find is to disconnect the little rubber fuel line near the injection rail, and actuate the fuel pump using a Smart laptop. (or run the car out of gas... that would work too!)

[Bum-bling-B]

Thanks - I was thinking about this on the way to work today as I was wondering what work it entailed since I'm at 160 miles on this tank and I just went to 1/2 a tank 10 miles ago. The mileage I am getting this time around I should be going to 1/2 at 190-200 miles.

Originally Posted by SmarTek-TNG

The tank has to be removed (or at least lowered.. you can get away with leaving the hoses and vent tubes connected as they have a lot of play) from underneath the car to replace the sending unit. A lift would be very very helpful, and I personally wouldn't want to do this without one. With a lift, it's actually not a very difficult job, although you do have to drain the tank first, and for this the easiest way I find is to disconnect the little rubber fuel line near the injection rail, and actuate the fuel pump using a Smart laptop. (or run the car out of gas... that would work too!)

[daleharrison]

Originally Posted by daleharrison

SmarTek-Thanks for the reply. I e-mailed my salesperson about the problem and he suggested I be very careful to fill the tank next time and monitor the gauge. If problem reoccurs then I will get in touch with Service Dept in Cary,NC. Otherwise, Smartie is doing fine. Again thanks.

Smart Tek--I wanted you and all to know--I filled up today and the gauge responded as it should. It now shows all bars darkened to the full mark. Problem solved with a little patience. Thanks again.

[renshi6]

Hey That Just Happened To Me Exactly...please Let Me Know What The Problem Is JELVIS AT COX . NET

[Bum-bling-B]

Just went through another tank and ALL IS OK? Problem fixed itself? More likely a problem with the gas pumps shutting off early twice? Hard to say but the last tank all is back to normal.

No gas gauge problem for my car. Knock on wood - 11k miles and NO PROBLEMS!

[johnssc]

The notion of driving until the tank is reading "0.0" fascinates me. Why would you do this? If you were flying, would you find this comforting if say United Airlines started doing this "just to see how accurate the gauges are?" and you were flying to LA? Do you like running out of gas or are you perhaps checking to see how much stress you can put a fuel pump under before it pukes it's innards out at you because it is now sucking air instead of fluid (which also keeps it cool).

FWIW, in 33 years of driving, I have yet to run across a vehicle gas gauge that is accurate. I tend to rely on them insofar as they give me a general idea of what I have left in the tank. My modus operandi has been to get an idea of what my gas mileage generally is and then reset the trip odometer at each fill. Then when I reach a certain mileage rather than a certain point on my gas gauge I stop for gas.

No vehicle manufacturer is going to invest big $$ into a unit that will measure the exact amount of fuel remaining in non-uniform container that is being carried in a vehicle that, for the most part is in motion and likely going up or down hills and subject to either lateral g-forces or g-forces from delta vee changes, not to mention the ugly tendency of the fuel to expand and contract based on temperature.

Of course this being the smart forum, the expectation will be that the gauge will be accurate to the micron...

[74AMX304V8]

as long as I knew they had a reserve I wouldn't mind. on 0.0 there is 1.3 US gallons left, for me that's over 60 more miles to drive, plenty to find a station.

[daleharrison]

Originally Posted by renshi6

Hey That Just Happened To Me Exactly...please Let Me Know What The Problem Is JELVIS AT COX . NET

renshi6--I am not sure what caused the problem. The gas gauge was not functioning properly when I picked up the car in Cary. I guess it took some time for the car to Smartin up?? Good luck with your situation.