No fuel light when run out of fuel.

[Jonb1760]

So Brains trust.
Ran out of fuel on the freeway🤬. Complete surprise as level was just above empty and NO fuel light on.???
Fueled up on side of the road10L, car started and fuel light came on??, drove the 1klm to the petrol station, (so close), but could only put 30L in.??
Drive home 380klms and gauge worked as expected. When I got home checked the OBD and showed FLI% @ 59%. Gauge showed about 40%.
So. From complete empty, 40L in a 50L tank?, And OBD with about the same error to fuel gauge. What could be causing me not to be able to access that last 10L?
Have some ideas but wanna ask the group.
Cheers.

[Sapphireho]

Did you have the fuel pump box out?

[Jonb1760]

Nope. Haven’t touched it.

[Sapphireho]

Originally Posted by Jonb1760

Nope. Haven’t touched it.

Do you have a flux capacitor? Good to learn they have twins in 2104.

Seriously, I got nothing.

[Ultramaroon]

If it was all highway (no sloshing) and the venturi pump failed for some reason, it wouldn't be able to pull fuel from the well opposite the fuel pump.

[Spuds]

Do you really mean that your car stopped running on the freeway? Why do you think you were out of fuel, what were the symptoms?

40L is about 10 gallons right? That's what I would expect to go in if the gauge was showing around 1/4 to 1/8th tank.

Any electrical or power (engine /exhaust/etc.) mods?

If it is fuel, it could be some wrong with the mechanism that moves fuel from the left lobe to the right.

[Spuds]

Originally Posted by Ultramaroon

If it was all highway (no sloshing) and the venturi pump failed for some reason, it wouldn't be able to pull fuel from the well opposite the fuel pump.

Well, I definitely started typing first!

[Ultramaroon]

Originally Posted by Spuds

Well, I definitely started typing first!

Haha...

[Spuds]

Monicaaaaaaaaa!

[Jonb1760]

Originally Posted by Spuds

Do you really mean that your car stopped running on the freeway? Why do you think you were out of fuel, what were the symptoms?

40L is about 10 gallons right? That's what I would expect to go in if the gauge was showing around 1/4 to 1/8th tank.

Any electrical or power (engine /exhaust/etc.) mods?

If it is fuel, it could be some wrong with the mechanism that moves fuel from the left lobe to the right.

So I know it ran out of fuel because lost all power had to change down gears while no power then it stopped as I pulled over and wouldn’t start, turned over fine but no go. Put 10L in on the side of the road and it started straight away.
40L from dead empty?? Then 30L at the station.
Invidia N2 exhaust about 18months ago.
Cheers.

[Ultramaroon]

So, what are your ideas? It doesn't sound like your picking up what we're putting down.

[Jonb1760]

Originally Posted by Ultramaroon

So, what are your ideas? It doesn't sound like your picking up what we're putting down.

Cheers 🥂 know what you guys are saying and am prepared to replace pretty well all the components in the system. Here’s what I think, there is more than 1issue. A Stucky sender unit for the inaccuracy between the FLI% and fuel gauge
A dodgy fuel pump/filter or hose between the two sides.
I just don’t understand why no Low Fuel Light came on and why it wasn’t grabbing the last 10L.

[Ohio Enthusiast]

Originally Posted by Ultramaroon

the venturi pump failed for some reason, it wouldn't be able to pull fuel from the well opposite the fuel pump.

Originally Posted by Spuds

If it is fuel, it could be some wrong with the mechanism that moves fuel from the left lobe to the right.

My thoughts as well. Based on refueling amounts it sounds like you ran the left side dry but the right side had some left (probably the missing 10 liters). Does anyone know how much fuel is enough to allow fuel to mix between the sides without pumping?

[Ohio Enthusiast]

Originally Posted by Jonb1760

A dodgy fuel pump/filter or hose between the two sides.
I just don’t understand why no Low Fuel Light came on and why it wasn’t grabbing the last 10L.

If there was fuel in the right side the ECU might still consider it enough fuel not to light the low fuel indicator - I believe there are fuel sensors in both sides. If the transfer pump failed you'd be left with fuel in the right side but no actual fuel getting to the engine.

A fairly easy test would be to drive some more until almost empty and open both access hatches (under the rear seats) and visually check the fuel level in both sides. Ideally you'd want to replace the butyl caulk and cap gaskets, but in a pinch I think you should be fine carefully reusing them.