When a player is running on fumes, extremely low gas <0.1% or so, other players on multiplayer can hear this sound effect - but not the player driving the car. I would think it should be the other way around if anything, but I don't see why both player and spectator couldn't hear it at the same time.

To know what I mean have a friend take a car (MRT) on a track (FE3) and add only 1% of fuel before leaving pits. Spectate your friend as they drive and listen very carefully, you will know when they are running on fumes and can tell them. As long as they aren't directly watching the F12 screen - you will know they are running out before they actually do run out - and yet the driver won't know.

If you hopped in the car and did the same, you wouldn't hear the sound, your only chance of knowing would be the F12 "break realism" screen.

yeah... but its not a extra sound of LFS. Your LFS thinks the fuel tank is empty and stales the engine but since the fuel tank isn´t really empty it puts the rmp back up at the next resinc.

That is the thing, when driving I do not get the sound, only someone spectating me. And the same happens if they are driving and I spectate - they don't hear it but I do. I doubt it has something to do with the fuel cutting out as a 'lag' like issue. It seems deliberately done, and is a subtle effect, that since it doesn't happen to the driver, it was rare to have caught.

Quote from blackbird04217 :

I doubt it has something to do with the fuel cutting out as a 'lag' like issue.

As I said in-server, I'm not sure exactly what you meant; the engine seem to cut out and the next instant the revs jump up. This went for a few seconds before the engine stalling.

Havnt tried this, would this sound show up in the mpr?

Dont think its an extra sound either, John is probably right.

yes what I mean is. You spectate someone and press "F12" and see the fuel level go 0.0. So LFS thinks the fuel tank is empty and stalls the engine.

The driver though still has lets say 0.0099999% fuel in there so he still continues to drive normal.

And since from the spectators view the fuel tank is empty it keeps stalling the engine. And since the guy you spectate is still driving normal it (tries) to keep the rmp in sync.

Except for the fact that LFS doesn't send fuel information to other players. Or is it?

Quote from Whiskey :

Except for the fact that LFS doesn't send fuel information to other players. Or is it?

It does. Among other things, it affects the vehicle's total mass.

Same is with tires, sometimes when u spec someone tires pop before they really pops so car keeps jumping while drifting lol ;p

Quote from John5200 :

You spectate someone and press "F12" and see the fuel level go 0.0.

Can you do that? I cant see anyone's fuel level. Either in F12 or from the in-car fuel gauge. I dont think that specific bit of info is viewable to anyone other than the driver itself.

i think i get his point...You might not see the fuel level as the one spectating, but the fuel level data is sent to evrione bcause of the mass-influence as mentioned before...

I'll have to try seeing if it appears in an mpr.

Like I said, I do not think it is a lag issue. I understand your reasoning and thoughts behind this being lag - but it doesn't sound like the engine is off / on. It sounds very deliberate like I said. I've witnessed it in the MRT at FE3. Perhaps there is something funny with lag- but like I said, it sounds deliberate. The volume changes and it doesn't sound like the engine is just off. It has a puttering to it, not turning on/off because of lag or fuel calculations - which yes would be sent to other players even if it isn't viewable in F12.

If I find some motivation maybe I will try recording it.

The explanation is (probably) quite simple; locally the fuel level is kept in a 4 byte float while the packet structure for vehicle position and status updates only provides a 1 (char) or 2 (short) byte int.