bureau13

I have never seen mine light up to indicate a low fuel condition. I keep forgetting to check if it is lit with ignition on...but if it's tied to the central warning "!" light, I can say for a fact the fuel low warning has not been issued.

My question: Is this a separate sensor from the level sensor that powers the gauge? My gauge "works," although at full it shows about 3/4, and it seems to bounce around between empty and almost empty when it gets low. I'm too chicken to attempt to drive it until the low fuel warning comes on though, so I have no idea how low it really is. I do believe my cluster needs to e cleaned, DeOxit'd, etc, FWIW.

Another question: Oil level warning. That must have it's own sensor....how low do you need to be to activate it? I've never seen this one either. I pretty much always seem to be a quart low, but never much more than that. I'm guessing this is why the underside of my motor is always a mess, no matter if I clean it. Does it make sense that I'd quickly leak out the "top quart" but not much after that? That seems odd to me, as it's a pressurized system and my oil pressure always seems fine.

davek9

IIRC the Fuel Level warning light is a separate wire/connection on the top of the fuel sending unit.

I think there are 3 wires one is ground and the other two are Fuel gauge and warning light.
The connector pulls straight up to remove it, its under the large round plastic cover that allows access to the top of the fuel tank.

Edit: the Oil Level sensor is located on top, left front of the oil pan, its a single wire that gets grounded when the level is low.

bureau13

Thanks for the info. I replaced the sender/tank gasket early on, to get rid of a bit of fuel smell in the cabin., and put some Deoxit on the electrical connections there. I guess that doesn't tell me that the sensor part is good, unfortunately...I just know that the fact that the gauge "works" doesn't imply that it is. Lol, the test for this is easy, I just don't want to run out of gas somewhere...

davek9

yes true, and so you should be able to test the circuit from the tank to the gauge.

hwyengr

Low fuel is both a light in the gas gauge and a "!" What's the greatest amount of gas that you've been able to fill up with when you thought the light should have turned on?

Oil level warning kicks in when you're about 2 quarts low.

bureau13

I don't think I've ever been able to fill more than 16 gallons or so.

hwyengr

Yeah, I bet you're just not getting low enough to trigger the light. Should be closer to 20 gallons gone before the light turns on.

I did 'test' mine. The needle spent a lot of time near R before the lights turned on, so there was a lot of worrying that the sender was broken. But it wasn't.

Even though it was expected, having the "!" turn on is scary.

bureau13

That pretty much is what I have suspected. I still probably won't test the limit unless I have to. Too much anxiety lol...

ltoolio

Chalkboss

First thing is to check the dash bulbs. Turn key to acc position and verify they light up.

Whitesands

Hi Jeff,
I've never seen the low oil warning light but have seen the low fuel light, I did on one occasion let the needle get just into the red, no light but when I filled up it didn't take anywhere near what an almost empty tank would, the needle doesn't reach the full mark when the tank is full either.
A few weeks later I thought I would test the warning light just in case I'm caught short so to speak, it will be nice to know system works, so I let the level drop till the needle just out of the red, still no warning, at this point I pulled the pipe off the tank and drained it, to my surprise I got almost 5gallons out.
The handbook says the light should come on with about 2US gallons left, so I put back in 2.5 gallons but when I went to start the car the warning light was on, well that proved the warning system was working, I then put another gallon in and the light was now out, I made a note of the mileage and went for a drive, all the warning lights came on after 11 miles so I estimate I have just under 3 gallons reserve. The needle by this time was way past the red mark.
Nice to know the system works even though the gauge is way off, I do plan to fix it sometime.

drwhosc

I have seen both light up. the Low fuel because I was out of gas and the Low oil because the sensor went bad. I even saw my coolant light come on due to a bad sensor.

If you want to test your fuel level light, just carry some gas in a can in case it does not light up, but as noted on a separate wire and is actually triggered by the sensor in the tank. You can unplug the wire back there and check the circuit back to the pod by grounding the circuit. That will make your light come on.

bureau13

That's a good idea, checking it electrically by grounding it. I will have to do that, thanks.

dr bob

Folks reading along should know that the digital dash ushered in a more conventional sender configuration. The 'low fuel' warning is generated from the tank level signal, and the separate switch and wiring for same are eliminated.

G.P.

I managed to get my fuel gauge working properly after checking resistance values all the way from the connection at the tank to the gauge at the pod itself, including pulling out the sender and checking that. after cleaning and re-connecting some wires, the gauge works as it should (I hope). it does stay on full for about 100klm's after filling but it goes to zero and the warning light works. I checked this by driving around with a spare jerry can full just in case.
Just to complicate things, my 928 is an 87 with an 89 digital dash installed. When I was checking the empty mark by driving around with a spare jerry can, the warning light was on and I pulled in to fill up when the digital part of the dash was telling me I had 1km of fuel left. I put 82 litres in the tank.

In regard to the oil level sensor, mine indicates low oil when I start it after having had the car parked in my steep driveway facing uphill. The oil pressure is O.K. and the level sensor cancels as soon as I'm out of the driveway. As someone has said previously, the oil level sensor is at the front of the engine, this is why the warning comes on after my car has been parked in my driveway.