So being a smart arse and trying to save a few quid I thought I’d leave filling up with diesel till the last minute so the mrs could get the discount voucher from the shops. The old computer said less than 10 miles and I noticed the turbo had stopped working. Is this some kind of fuel saving device the car does when it’s really low?

I think most things are cleverer than you mate. 😀

Possibly went into a limp mode, what car is it? Did you notice engine light, and/or a warning come up on dash ?

Possibly went into a limp mode

This normally happens to me when I take on too much fluid, not too little.

There are pills to counter that samurai!

Mine tells me where the nearest petrol station is if I go into the reserve tank……

Yes. (because it is designed and developed by people like me……. 😉

Generally, most OEMs don’t alter the pedal map or remove boost etc at “low fuel” levels because you still might need full throttle in an emergency situation, even if you are low on fuel!

What they do do however is to introduce a calibrated misfire or “hesitation” into the engine when fuel level gets critical (generally, when the system starts to have trouble maintaining a set fuel rail pressure). That misfire isn’t a “real one” it isn’t caused by low fuel, but is done to alert the driver to the fact they really need to fill up!

When the system finally cannot maintain a fuel rail pressure due to lack of fuel, it will cut the engine completely, but only if it is at low speed / idling. Otherwise, the engine will continue to run normally right until the point it stalls due to lack of fuel!

^that is exactly what happened^ however it definitely killed the turbo prior as I was trying to accelerate down the dual carriageway to see if it was killing the boost. No lights just no boost. Mazda diesel sport.

Could of course be a bit of water in the diesel, which might only show in a low tank, and would also kill the turbo.

But would probably light an engine warning light.

I’d be surprised if the EMS deliberately limited engine torque (for the safety reasons i mentioned before), more likely, that the fuel rail pressure fell at that moment (especially if fuel had been “sloshing” in the tank (accel/cornering etc) and there simply no fuel availible to make torque/boost

I’d have thought there’d be plenty of fuel left in when the computer said 10 miles though. Generally those things are pretty pessimistic, for ovious reasons. I knew someone who drove on 0 miles remaining for a good 30 miles.

However, if it’s Ford, it may not really know how much fuel it’s really using…

maxtorque makes perfect sense, two Transits I have develop a ‘missfire’ as soon as the trip computer goes to 0. However, it also seems to drop through the last 10 predicted miles in two or three jumps over about two miles…

@Wrighty – lots of s-h-one-t sloshing around in the bottom of your fuel tank, running down low means it gets sucked into the engine. I always try and fill up with 1/4 tank remaining, diesel can be particularly bad / dirty. As for the range calculation it’s just an educated guess, the car isn’t smart at all in this regard (that doesn’t mean it’s not smarter than you though – lol – too easy that)