urdrwho Posted June 27, 2013 Share Posted June 27, 2013 I'm trying to test the accuracy of the fuel gauge and want to run it low enough that the low fuel light illuminates. I've owned this car for a few months, don't drive it daily and never saw the low fuel icon when the dash lights go through their start up routine. I don't know if I have a burnt out bulb or maybe it is an icon that isn't part of the start up routine. I don't want to be running a how low can you go test with a burnt out bulb. Link to comment Share on other sites More sharing options...
Sludgeroo Posted June 27, 2013 Share Posted June 27, 2013 I've gone super super low (at the E mark) and then only put in 10 gal. Ours has 15.9 gal tanks, and my low fuel indicator never came on. Link to comment Share on other sites More sharing options...
Stang70Fastback Posted June 27, 2013 Share Posted June 27, 2013 The low fuel indicator doesn't come on until you have 2-ish gallons left, which occurs when the needle is ON the 'Empty' line. I've run it past the 'Empty' line with the light on for a while and still had a gallon left when I filled it. ...and no, the light does NOT illuminate when you start your vehicle. You'll have to run it down in order for it to come on. Link to comment Share on other sites More sharing options...
pleaidestar Posted June 27, 2013 Share Posted June 27, 2013 I have to go by mileage or else I don't have a clue where my fuel is, it fills up all the way but the needle drops quick, by Wednesday ill have used like maybe half tank and the needle is under the E...should take care of it but it won't just be the guage I replace want to do the lights red and stainless bezel at the same time Link to comment Share on other sites More sharing options...
Stang70Fastback Posted June 27, 2013 Share Posted June 27, 2013 I have to go by mileage or else I don't have a clue where my fuel is, it fills up all the way but the needle drops quick, by Wednesday ill have used like maybe half tank and the needle is under the E...should take care of it but it won't just be the guage I replace want to do the lights red and stainless bezel at the same time Doesn't sound like a gauge issue. Sounds more like a sending unit issue, which is accessed from the interior of the vehicle at the back (there is an opening into the tank that holds that and the fuel pump.) It's not a terribly complicated job. Link to comment Share on other sites More sharing options...
pleaidestar Posted June 27, 2013 Share Posted June 27, 2013 Is that thing replaceable or is it part of the assembly? I have changed the pump twice in the three or so years I have had it but don't remember if it parts with the float Arm and electronics in there. Link to comment Share on other sites More sharing options...
Stang70Fastback Posted June 27, 2013 Share Posted June 27, 2013 Is that thing replaceable or is it part of the assembly? I have changed the pump twice in the three or so years I have had it but don't remember if it parts with the float Arm and electronics in there. Well I have replaced JUST the pump, so the pump does separate from the rest of it. Not sure what else comes apart, but from what I vaguely remember it was just a bunch of parts that you could probably disassemble rather easily... maybe. Link to comment Share on other sites More sharing options...
pleaidestar Posted June 27, 2013 Share Posted June 27, 2013 Ok..but the fuel sending unit is part of the fuel pump assembly right, the whole assembly will more than likely need to be replaced for the guage to read correctly? Link to comment Share on other sites More sharing options...
Kennyfvholla Posted June 28, 2013 Share Posted June 28, 2013 Ok..but the fuel sending unit is part of the fuel pump assembly right, the whole assembly will more than likely need to be replaced for the guage to read correctly? There are two sending units. One on the drivers side, and one on the passenger side. The fuel pump is located on the passenger side sending unit. They can be separated and are replaced separately. There are two sending units because of the hump in the center of the tank. When one stops reading correctly, the gauge drops exponentially faster as the actual fuel level drops. Link to comment Share on other sites More sharing options...
pleaidestar Posted June 28, 2013 Share Posted June 28, 2013 Sweet! thanks kenny is the driver side sending unit under the smaller plate under the rear seat like the pump assembly? I have seen that access the last time I did my pump but didn't think to remove it to have a look. Link to comment Share on other sites More sharing options...
Kennyfvholla Posted June 28, 2013 Share Posted June 28, 2013 Yup Link to comment Share on other sites More sharing options...
johnegg Posted June 28, 2013 Share Posted June 28, 2013 the gauge displays resistance. the sending units measure resistance. as the float arm moves, the contact moves across a ''something or other'' that looks like a wire winding. and there is more resistance on one end, E i think, than there is on the other end. but in any event, over time the ''something or other'' ages, and the unit does not read accurately. more resistance means a lower gauge reading. i have heard that cleaning the contact points can help. one idea was to use a pencil eraser. another idea is to run some ''techron'' fuel system cleaner through the tank once a year or so. i have done this with limited success. i revived a 95 lego gauge from no reading to works ok with techron. the car sat for 18 months and the gauge did not read any thing . one tank with techron got it working some. the second tank got to work in what i would call ''old subaru gauge syndrome''. it reads full when full, it reads enpty when there are 10 - 12 gals gone, or 4 - 6 gals left. (15.9 tank) i suspect this percentage is the passenger side vs driver side percentage, but i do not know. i have wondered if jumping out the driver side unit would make the gauge more accurate on half? of the gauge. in other words, if the gauge thought the driver side was always full (instead of empty) you would run out of gas when the gauge hit 3/4? tank, every time. and the light would come on when you hit 5/8s, maybe. this might be ok if you know your car, but not so good for a forgetful wife or girlfriend or a new buyer. jumping out the driver side unit may be a way to test the low gas light. but the easiest way is to keep track of your miles/ gallon and your miles/ tank. if a fill up when at E is only 10 - 12 gallons the gauge is not accurate and the light will not come on. if a fill up is 14 plus gallons, the light should come on. once you know how many miles you drive in each gallon, drive the car 15 gallons worth. the light will / should come on at around 2 gallons left. Link to comment Share on other sites More sharing options...
twisty Posted June 28, 2013 Share Posted June 28, 2013 in my 95 the needle will hit the E and only be 10 gallons down. the light comes on regularly with about 12.5 gallons down. ive ran it till it sputters and only been able to put 13.5 gallons to fill it, which makes me wonder about the pick up tube on the fuel pump. my 96 will hit E at about 13 to 13.5 gallons, but doesnt sputter out until i have less than a half gallon in the tank. it would cut out on turns, but i still was able to drive it 2 more miles to a station to fill it up. 15.72 gallons. the low fuel light seems to come on at different levels all the time tho, sometimes it will be 12.5 gallons down, sometimes 14 gallons. Link to comment Share on other sites More sharing options...
johnegg Posted June 28, 2013 Share Posted June 28, 2013 the low fuel light is triggerd by a different sensor than the fuel level sending unit. it is controlled by a thermo coupler? sensor? or something. basically, when it is NOT covered by fuel, it heats up and triggers the light. my son's 95 used to turn the light on at about 13.5 gone, but then the next time he started the car, it would not come on. that was dangerous. Link to comment Share on other sites More sharing options...
Stang70Fastback Posted June 28, 2013 Share Posted June 28, 2013 it is controlled by a thermo coupler? sensor? or something. basically, when it is NOT covered by fuel, it heats up and triggers the light. Aha! THANK YOU for finally explaining why those lights always fade in and out so gradually. I've always wondered and never looked into it. Link to comment Share on other sites More sharing options...
TexasLegacy2.5GT Posted June 30, 2013 Share Posted June 30, 2013 Oh, don't even get me started on the low fuel light issue.... Kenny will tell you all about my BS with this venture. I've ran the car twice till it was almost completely out of gas and not low fuel light....I've installed another fully functional gauge cluster and no low fuel light. I've never seen it in the 2 years I've owned the car. It's another enigma I need to solve. However, my cars fuel gauge reads very accurately. Link to comment Share on other sites More sharing options...
Kennyfvholla Posted June 30, 2013 Share Posted June 30, 2013 Yerp de derp lol Link to comment Share on other sites More sharing options...
johnegg Posted June 30, 2013 Share Posted June 30, 2013 bad bulb? Link to comment Share on other sites More sharing options...
TexasLegacy2.5GT Posted June 30, 2013 Share Posted June 30, 2013 bad bulb? That would mean a Bad bulb on BOTH the clusters I installed. I doubt it but it is a possibility. Since the gas gauge always reads correct I have just given up and moved to more important problems. Lol! Oh well, it's a fifteen year old car it's going to have "isms". Link to comment Share on other sites More sharing options...
urdrwho Posted June 30, 2013 Author Share Posted June 30, 2013 I ran it low to the point the needle was covering the "E" -- about half way into the "E". No fuel light. We had to go someplace that was out in the country, where gas stations are far and few between. I had to fill up because I wasn't testing my luck in the middle of no where. Link to comment Share on other sites More sharing options...
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