545svk

Hi. My fuel gauge is very random and I have no idea if the warning light work. I would like to push the range a bit and see what happens.

Can running out of fuel damage any components?

I thought to put a jerry can in the back and drive on the trip meter till I either calculate it should be empty or the light come on.

Thanks in advance

The Forgotten On

It may cause damage to the fuel pump because the fuel is what lubricates its bearings and if there is no lubrication, the fuel pump can jam and fry the relay and the fuse.

You won't get any bad contaminants in the engine because of the fuel filter but you may cause knocking as the car will run lean.

Replace your fuel gauge sender as that is often the problem and very seldom is it the gauge.

outbackgeorgia

Well, on an 87, the fuel pump will stop as soon as the engine quits, as no signal from the EZK will drop out the fuel pump relay.
I can't see how running out of fuel will be an issue.
Dave

jcorenman

Rear bumper, depending on the traffic situation at the time.

Does the "reserve" light work? (Red indicator at the bottom of the scale). That is connected to the same sender unit but on a separate switch contact, so even if the sliding-resistance sender gets gummed up it will usually still work.

daveo90s4

Front bumper, depending on the passing manoeuvre at the time

545svk

Damage to the bumpers should be limited, I am out in the country. Might get licked by a cow while refueling.

The reserve light work together with the warning lights on the dash. After asking the question I thought an easier and safer solution can be to siphon the fuel into jerry cans.

Will do that the weekend and see if the sender send a signal.

GregBBRD

When virtually every car I worked on was a 911, we would have a car which ran out of fuel, with a stuck fuel level sender 3-4 times a year towed in.

About 90% of the time we'd add fuel, replace the sender...no harm, no foul.

The other 10% would be different....the fuel pump would leak out of the end cap, where the o-ring was.

Couldn't figure out what was happening, for years. Finally took one apart...and realized that the pump armature was submerged in fuel....and being a DC motor, I figured that there was "sparking" going on. No problem if submerged in gasoline...but introduce some air....not the best combination.

Once had the opprotunity to talk with some "Bosch Experts" at a Bosch class. At the end, they asked if anyone had any questions....and if course, I did.

Those guys had a really dumbfounded look on their faces...and simply had no answer, when air is introduced into the pump with gas and sparks.

I've always been very careful to not run out of gas, on my own vehicles....

545svk

Thanks GregBBTD - good knowledge to have.

Dave H.

engineers don't like not having answers. they make funny faces.

FiveElements

I have to agree. What is odd is on sharp left turns, my car cuts out for brief moments until I level straight again. Even with a nearly a 1/4 tank of fuel. Now my fuel pump is bad. Ordered a new one last week. Also had the in-tank pump fail about 10 months ago. Greg Brown replaced that for me fortunately while I was in the LA area. So that probably strained the main pump too.

G.P.

I found on my 87 S4 that cleaning all the grounds that I could find, and replacing the battery negative and engine ground cables made the fuel gauge much more accurate. I also cleaned the connections at the back of the instrument cluster.
Apparently the sender unit has 2 very fine gauge wires, these would be very susceptible to any resistance to poor contacts anywhere in the circuit.
The sender unit in mine had been replaced by the previous owner about 1-2 years ago. It didn't function correctly until I cleaned all the connections.

The Forgotten On

Do you still have the plastic container thing at the bottom of your fuel tank? If you do not have it or the top has popped off, that is the reason why. It holds fuel so that the K-Jet cars won't lose pressure and shut off while making turns.

The fuel tank never changed after early 78 so all of our cars have it. Check inside of the tank from the point where the fuel level sender mounts.

whatudrivin

Picture time. Here is what it looks like and the top is off here. Granted this was my tank that had gas sitting for 13+ years. Very very nasty stuff. Cleaned up nicely though!

17prospective buyer

Probably more potential for damage on K-Jet though.

mark kibort

the armature wouldnt be sparking, but at the brushes and commutator.... that could be a source of ignition! I wonder if that part is sealed off.

you dont have to worry about running lean, because lean is actually very good for the engine....... not so good for emissions.....stoich is what you want to worry about, and usually if you go lean, you go real lean which is only a problem for how the engine runs, or doesnt run.