Low Fuel Light?..is there a way to test it?

[Boxer_Airhead]

Since I have owned my 81' Euro SC, I have only filled up gas about 5 times. I don't anticipate on every letting the fuel tank get very low before I fill-up.

But, I am wondering can I test my low fuel light somehow without just running my tank close to empty? Are there wires coming out of a fuel level sensor that I can use to simulate that the tank is low?

[Formerly Steve Wilkinson]

Why not just put a jug of gas in the trunk, as your gauge approaches empty--a gallon or two in a rinsed-out detergent jug, whatever--and let the car run dry, see how accurate the light is? That's an easy real-world test and is much more accurate and realistic than probing wires.

Oh, and please, all the nannies who will tell you that we'll all die if you rear-end somebody while you have a jug of gas in your trunk...chill.

[HarryD]

Or, after you put the jug in your car, run it down until the light comes on. If you are near a fuel station, fill up and see how much it takes, subtract it from the listed capacity and then you will know your reserve.

I know my car can go about 30 miles (about 2 gallons) with the light on.

Stephan, of course the gallon can won't be the problem, only the 16-18 gallon container next to it

[PCA7GGR]

Why not...

take the tiny bolts (that secure the sending unit in the tank off), turn the key on, sowly lift the sending unit straight up out of the tank and have a friend (or significant other) tell you when the low fuel light goes on. Stop lifting it out when the light goes on. Wait a bit and then lift it out completely. Based upon how high the wet mark is, "guesstimate" how much gas is left i the tank when the light goes on (should be around two gallons).

[Boxer_Airhead]

Originally posted by PCA7GGR
Why not...

take the tiny bolts (that secure the sending unit in the tank off), turn the key on, sowly lift the sending unit straight up out of the tank and have a friend (or significant other) tell you when the low fuel light goes on. Stop lifting it out when the light goes on. Wait a bit and then lift it out completely. Based upon how high the wet mark is, "guesstimate" how much gas is left i the tank when the light goes on (should be around two gallons).

This is what I am asking about. Yet, I mostly just want to know that the light does turn on, not necessarily how much fuel is left.

Can you point me in the right direction to find the sending unit? If I remove the sending unit and then as you suggest turn the key, does that mean I should be running the engine or just turn the key until the battery comes on? Also, is there any reason I should be concerned about ruining the sending unit upon temporary removal?

Thanks for all the responses thus far.

-Myles

[Boxer_Airhead]

Originally posted by Formerly Steve Wilkinson
Why not just put a jug of gas in the trunk, as your gauge approaches empty--a gallon or two in a rinsed-out detergent jug, whatever--and let the car run dry, see how accurate the light is? That's an easy real-world test and is much more accurate and realistic than probing wires.

Oh, and please, all the nannies who will tell you that we'll all die if you rear-end somebody while you have a jug of gas in your trunk...chill.

Wont I be hurting the engine if I let it run dry? Or is it just the constant attempts at starting a car with no fuel that really dries things up?

As you mentioned, I do agree this is an accurate test.

[TerryH]

My 81 euro had a gas gauge that was very accurate when sitting still. They are too active when gas is sloshing. Newer cars use electronics to slow the readings so there's less fluctuation. On my car, when the low level light stays lit, it is time to find a station in the next twenty miles or so. I have put in 20+ gallons and I think the tank holds 21.

[KFC911]

I was always used to pushing the limit on the "low on fuel lights" on EVERY car I've ever had (without running out) until I purchased the 911. Out for a drive one evening, and the light comes on as I'm returning home (I don't recall how far, but it wasn't on THAT long). She left me stranded a few hundred yards from my house as I left the next morning (heading to the gas station). Now, when the 911 light comes on, I find a gas station

[ossiblue]

I too would like an answer to Boxer_Airhead's original question--is there a simple way to test the light. My 75 gauge needs cleaning as the needle often sticks and needs a "tap" on the lens to move sometimes, therefore I don't trust the reading as the needle approaches empty so I don't have a clue if the light actually works. I have done the sender removal test on my other p-cars to check the light, but I was hoping there was a simple "wire test" just to see if the light actually lights. Anybody?

[PCA7GGR]

Myles,

The sending unit is the round unit with the square black plug (with wires leading from it) that is connected to the top of the gas tank. To test the unit, you just need to turn the key so that the dash gauges are activated.

I will let the light flicker for a while but fill my 911 once the light glows steady. On my never cars, once the low fuel light goes on, I still have at least 50 miles of gas left. The 911 sending unit is a less realiable, less accurate floating mchanical indicator - the newer cars have more accurate electronic units.

[jstobo]

Pull the plug on the sender. Jump the pin(in the plug) marked with a w(ithink) to ground. Light should come on. There are only three pins(female) in the plug. One is a ground, one is for the needle, and one is for the reserve light. If my letter designation I used above is incorrect due to failing memory try another pin. Easy.

[Formerly Steve Wilkinson]

Excuse me for asking a secondary question, but since people who know how the fuel gauging works are looking at this thread...

My low-level light used to work fine. Then I installed a Fuel Safe fuel cell. Gauge (needle) works fine, and accurately, but I no longer have a functioning low-level light. Is there a reason for this--i.e. fuel cells are configured differently enough that they don't have a low-level-light function?

[ossiblue]

Thanks, jstobo.

[David]

I tested mine once, it cost me a tow truck ride

[Dan in Pasadena]

Originally posted by Formerly Steve Wilkinson
Excuse me for asking a secondary question, but since people who know how the fuel gauging works are looking at this thread...

My low-level light used to work fine. Then I installed a Fuel Safe fuel cell. Gauge (needle) works fine, and accurately, but I no longer have a functioning low-level light. Is there a reason for this--i.e. fuel cells are configured differently enough that they don't have a low-level-light function?

Steve, I don't know the answer for certin but what occurs to me, is the fuel cell metal? Perhaps you lost the ground after installing it?

[Formerly Steve Wilkinson]

Yes, it's metal--aluminum--and is affixed directly to the pan of the car, so there's plenty of grounding. Also, the gauge works--just not the light.

[RoninLB]

The low level bulb is ok but the mechanicals don't work..


the two pins and disc make contact at low fuel level.
it's not the greatest design and is subject to connection probs from wear and tear or just crap build up.

notice the two tits at opposite ends









and if you remove the sender you should install a new gasket. I used the rubber kind instead of the leak prone one. The rubber will raise the sender about 1/8" giving greater "emergency" fuel.
pn should be 477 919 133, but confirm

[plymouthcolt]

Originally posted by Boxer_Airhead
Since I have owned my 81' Euro SC, I have only filled up gas about 5 times. I don't anticipate on every letting the fuel tank get very low before I fill-up.

But, I am wondering can I test my low fuel light somehow without just running my tank close to empty? Are there wires coming out of a fuel level sensor that I can use to simulate that the tank is low?

Yes...don't put any gas until it turns on. It not that hard...your car will not sudden;t spuuter and stop. on my car when it hits the final line the light comes on and just have a gallon jug in the car in case.