General Panda 2008 Fuel Gauge erratic readings

[GaryinAmsterdam]

Apologies if this has been discussed many times recently. I'm new to Pandas and Fiat fuel gauges. I have the 1.2 2008 model, 5 speed. I fill the tank near work, drive 45 km home, the gauge is now 1/8th from full, the "KM to empty" reading is anywhere from 600-700 km. In the morning, I start the car, the gauge is now down to 1/4 tank and it's 450-550km to empty. It does this everytime time I turn the car off after a drive of some distance.

I still get about 5.6/100 km average (seems consistent with others) and go about 480 km per tank until the light comes on.

Is this normal for others?

Conversions:
45 kilometers is approximately equal to 27.962 miles.
450-550 kilometers is approximately 279.62 to 341.78 miles.
Therefore, 5.6 L/100 km is approximately equal to 50.44 miles per gallon (UK).
5.6 L/100 km is approximately equal to 42.00 miles per gallon (US).

 

[koalar]

Sounds normal

50+ miles per gallon is above average

The trip computer is normally all over the place straight after you hit the reset button, but is pretty accurate if you leave alone it for thousands of miles

It works on average, so if you fill up at the top of mountain reset the the trip and coast down the range will be stupidly high, and the other way round if you fill up at the bottom, but over time it averages out pretty good

If you drive till warning light is almost on, switch off for an hour or so when you switch it back on the light will be on I guess about the thickness of the needle difference maybe a touch more lower on a cold start

As the computer uses this level there is a discrepancy when you start a journey, also the miles to empty change depending on your current usage, so less miles when engine cold.

 

[GaryinAmsterdam]

Sounds normal

50+ miles per gallon is above average

The trip computer is normally all over the place straight after you hit the reset button, but is pretty accurate if you leave alone it for thousands of miles

It works on average, so if you fill up at the top of mountain reset the the trip and coast down the range will be stupidly high, and the other way round if you fill up at the bottom, but over time it averages out pretty good

If you drive till warning light is almost on, switch off for an hour or so when you switch it back on the light will be on I guess about the thickness of the needle difference maybe a touch more lower on a cold start

As the computer uses this level there is a discrepancy when you start a journey, also the miles to empty change depending on your current usage, so less miles when engine cold.

This is great. Thank you. I think I did the calculations correctly. I'm used to kilometers and use the Fuelly website/app. I've been resetting after each refuel, but only bought the car in April. Before I bought a locking Gas cap, I thought someone was siphoning my fuel at night!

So the advice is to leave the computer alone for a month or so, no reset. I guess it doesn't really matter since the "miles to empty" resets on it's own anyway.

 

[jrkitching]

5.6l/100km is 50mpg (UK).

About what I'd expect from a normally driven car used for a typical mix of urban & motorway driving.

Three things which greatly affect mpg in the 1.2 are cruising speed (mpg drops off quite quickly above 55mph), journey length (the first few miles from cold will use much more fuel) and temperature (consumption is noticeably higher below 5C).

Thermostats are known to leak internally due to seal failure as they age; if this happens, the engine won't reach operating temperature and fuel economy will be significantly worse; it's the first thing to check if you ever notice an unexplained drop in economy.

 

[GaryinAmsterdam]

5.6l/100km is 50mpg (UK).

About what I'd expect from a normally driven car used for a typical mix of urban & motorway driving.

Three things which greatly affect mpg in the 1.2 are cruising speed (mpg drops off quite quickly above 55mph), journey length (the first few miles from cold will use much more fuel) and temperature (consumption is noticeably higher below 5C).

Thermostats are known to leak internally due to seal failure as they age; if this happens, the engine won't reach operating temperature and fuel economy will be significantly worse; it's the first thing to check if you ever notice an unexplained drop in economy.

This is great information. The mileage was a bit worse in last night's fuel up. The Panda is having service on Monday and I'll mention this to the mechanics. I appreciate the advice.

 

[jrkitching]

The mileage was a bit worse in last night's fuel up

There's bound to be some variation because it's not possible to fill the car to the same point every time.

IMPORTANT:

The fuel system needs a minimum airspace of around 5 litres to work correctly. You must NEVER attempt to put more fuel than this once the automatic pump has shut off for the second time.

If you dribble fuel in past this point, you will lose the airspace necessary to protect critical emissions control components like the evap solenoid and charcoal canister. This can cause serious, expensive damage; at least one person has posted here that the bill was considerably in excess of 1000 euros.

The handbook has a clear and specific warning against putting too much fuel in the tank.

 

[GaryinAmsterdam]

Thanks again for this information. Makes me wonder how many times this could have occurred by the previous owners. I did not know that about topping off like that, although, I never did that because I watched someone get soaked with petrol one time doing that.

The car runs a lot better after the service yesterday! They put "fuel additive" in there, (it's on the receipt)....any clue what they used? Is this something to use often?

 

[A3jeroen]

Injectorcleaner?

gr J

 

[GaryinAmsterdam]

Injectorcleaner?

gr J

I guess that makes sense. Something that would only be used periodically I assume.

 

[jrkitching]

Makes me wonder how many times this could have occurred by the previous owners.

You can say this about quite a lot of things with any used car purchase.

A used car that you've owned from new might be worth quite a lot more to you than a similar used car on a dealer's forecourt, because you know all of its history.