Fiat Fuel Capacity

[SteveW]

A question for Fiat owners.

I drove today until the computer said I had 80 kms to go until empty. At about 80 kms to go the count down ceases and the message says "fill up"or similar. At the same time the low fuel light came on. I drove approximately 25 kms further then filled the tank. It took 100.06 litres precisely. Given that the tank purportedly holds 120 litres, has anyone had experience with going closer to the limit?. By my calculations on a good day the extra 20 litres will go up to 200 kms and on a bad day more like 140 kms.

[BruceS]

Steve (or T1?) do you know if the bypass diesel is used for helping cool the injectors?
Steve next time you ever get down that low put your hand on the bottom of the fuel tank and feel how warm/hot it is.
If it was similar to "some" Cummin's engines you can do expensive damage if you run the tank dry.
Do you know how hard that engine is to bleed or does is 'self bleed'?

Oooops! sorry.......... I'm not a Fiat owner and will never be one!

[SteveW]

Self Bleed.

Plastic tank - probably not much help for touchy feely.

I have no reason to doubt that there isn't 20 litres left. Needle was not at the bottom.

I guess I am hoping to find out "how low can you go" via someone else's mistake.

[norman]

Steve we have a Peugeot boxer motorhome in NZ the diesel tank holds 69lts and gives about 400kms the book says i have about 25kms to go when the warning light comes on .

[dapope]

The bosses citroen has a warning light that comes on @ 115k, however with careful driving it can be made to make fuel back up to 125.
lowest its been down to was 50
Got 64l into a 60l tank
I am reasonably sure the plastic tank has stretched as when new 58 was the best we could do
4.5l per 100, so it does go a long way...

[BruceS]

Martin you should maybe report instances of suspect measures.
Each state has a "weights & measures" department to check scales and metering equipment.
Having been involved in the fuel retailing business I can assure you the majority of owners know how to tweak their fuel pumps.

[Izabarack]

It took 100.06 litres precisely. Given that the tank purportedly holds 120 litres, has anyone had experience with going closer to the limit?. By my calculations on a good day the extra 20 litres will go up to 200 kms and on a bad day more like 140 kms.

Just how precise do you reckon that number is? I happily use one particular pump at one particular servo what gives me a good 10% more than indicated. I seriously do not trust fuel bowsers, purported figures, or reminder lights, with any degree of confidence.

Bit hard when dealing with upwards of 120 litres, but I helped a friend measure some fuel things on his MH. We started by emptying the fuel tank with the MH on level ground. Big bung in the bottom made things easy and drained fuel went into Jerries for the moment. Bung back in, then measured fuel back into the tank until the low fuel light went out. I forget his figures now but it was a lot more than expected. We then proceeded to fill the tank until the level was just visible in the filler tube after burping. Numbers were a full 4 litres higher than nominal figure in the owners manual. Mate now knows what the tank really holds and what is left when the Low Fuel light comes on. As he does keep a close eye on consumption figures, he always has a pretty good idea of how far he can get with the current fuel load.

One rider though, mate's fuel pump returns 5 of every 6 litres to the tank as a method of cooling fuel pump. After a long drive, a feel of the tank shows it is quite warm. I would be very careful to never run the tank dry on any diesel that uses fuel to cool the fuel pump. A couple of diesel mechanics have said you will get away with it a couple of times but even one time will cause some damage if the fuel pump overheats. Perhaps the low fuel light setting in the Fiat is intended to give some measure of safety by ensuring the fuel pump remains cooled.

Iza

[T1 Terry]

That is correct, the low fuel light is warning you that this is the limit to still be able to keep the fuel system cool. Diesel fuel overheated dumps a lot of it's rubbish through the system resulting in early injector clogging and contaminated fuel lines. The fuel not only cools the pump, it cools the injectors as well, if the fuel is already hot when it gets there the level of cooling is reduced.
The next problem is cavitation, small amounts of air get sucked into the fuel pick up and the extreme pressure the pumps run at these days, those air bubbles are worse then iron filings at tearing pump bodies to pieces. Finally, the diesel fuel is the lubricant for the fuel system and it becomes as abrasive as kero when it gets overheated.
You might be able to get another 100km from a tank full, but it might require the Fiat dealer to replace the components in the fuel system afterwards.
Even petrol engines with fuel injection shouldn't be run too long on the low fuel light, the fuel is a coolant and lubricant for them as well.
On the big CAT engines in the tower cranes, there is a fuel cooler added in the return line before the fuel returns to the tank where the crane will be used in warmer climates like Aust, it helps stop the fuel over heating in the big fuel tanks and waxing when it gets cold overnight.
One crane was shipped to China with 1500 ltr of fuel in the tank, it took them 3 days with heaters in the tank to melt the solid waxed fuel, there are a lot of lighter elements in winter fuel that will boil off if the fuel gets hot.

[SteveW]

I suppose this raises the question; What fuel capacity should be quoted in advertising blurb? Should it be the useable amount of fuel - thereby giving an indication of the travelling distance of a vehicle before needing to be refilled?

As an aside, I recently sold a Holden Rodeo (2008 as in Isuzu) diesel that had a fuel cooler in the return line to the tank. It was similar to a transmission oil cooler - for anyone who has one and wants to look it was located under the vehicle on the left side roughly beneath the rear of the front passenger seat. It lies flat, parallel with the floor.

[Chuck]

The 'useable' amount of fuel will vary from driver to driver... much better simply stating the capacity of the tank - 100L etc.