How To Confuse The Fuel Guage

[hertsnminds]

Found a new C3 trick yesterday. Having filled up with fuel and 6 lights on the guage I drove about 80 miles, at about 60 the first light went out, as usual.

Then I parked the can on a hill sideways (it was in a car park) so the passenger side of the car was lower than the drivers side.

When I started up the fuel guage was back to 6 lights and stayed there for another 60 miles. This meant the MAX indicator thought there was a further 410 miles in the tank (it's usual full reading) even after travelling 80 miles. Now I would be very pleased to get 500 miles from one tank but with the average MPG reading its usual 44 this is not going to happen.

So now I am going to have to guess when I am low on fuel (or work it out from the trip milage). Just hope things reset at the next fill up.

Ian
Orange 03 Senso

[bencowell]

Thats interesting, because the C5 guage is rock steady no matter what angle you park at. My Saxo and Xsara were sensitive to angles, the Saxo even changed the fuel level when driving round long flat corners.

I understand the C5 dashboard readout works on a combination of the computer showing what it thinks there should be in the tank, and the levels reported by the tank sensor.

[dave leatherby]

Hi Ian

Dont know about the fuel guage, but I'm confused!

Filled tank to pump cut-off - LCD said max 350 miles. Ran til 3/4 empty - refilled tank - worked out miles done against fuel used - this gave approx 35 mpg. (LCD again gave 350 miles range full). Tank holds approx 10 gallons - therefore 35mpg X 10 galls = 350, OK?

Now my LCD average mpg (reset LCD from full) shows 44 mpg over that last refill!
Am I missing something - or is it just old age?

[hertsnminds]

Don't work it out from the MAX MILES do it from the actual miles travelled on the odometer

Gallons = Litres /4.546

so if you can put in 30 litres that's 30/4.546 = 6.5992 gallons

If you travel 350 miles on this you have done 350/6.5992 = 53.036 mpg

If you are getting 10 gallons in the tank that would be 10 * 4.546 = 45.46 litres
(The most I have ever been able to get in the tank is 42 litres)

so 350 miles at 44 mpg uses about 7.9 gallons = 35.91 litres

35.91/47 = 76% or about 3/4 of the tank capacity
So 350 miles on 3/4 of a tank at 44mpg is about right!

To sum up

Actual mpg = miles travelled since fill up / (litres put into tank/4.546)

Now all that is starting to sound like a Citroen dealers explaination of an issue you have with the car, maybe I should just have said...they all do that sir!


Ian
Orange 03 Senso

[dave leatherby]

Wow Ian!!!!

Now I know my last remaining greycell has also had it!

I'll try to understand your explanation tomorrow am - before my afternoon nap! (Poor old s-d)

Anyway, initiall impression is that alls well?????

Car back from dealer Friday - unused from mid-day Saturday til mid-day today (Monday) Guess what - clutch judder! Not too bad but definately present, as are clacks from behind right ear. Back to dealer tomorrow - they'd adjusted handbrake so that, with much effort, one can just get it on first notch (not possible for the missus though!) :unsure:

PS. Um - had another read! I set the trip odometer to zero with tank full and noted pump reading when again refilling, dividing litres by 4.546 against miles run.
Oh Lord! Now I dont know which is left and right! Two blokes in white coats knocking on door!

[dave leatherby]

Hi Ian

Rechecked my figures and my original were correct approx.
Fundamently my mpg over some 250 miles was 35 mpg, but the given average mpg on the display that I'd zeroed on previous re-fill was 44mpg.

The 350 maximum display range after refill to cut-off was obviously the computers estimate based on the previous comsumption. ie. 35 mpg.

The average display mpg (44) would therefore seem wildly inaccurate? (Not that it's vital - it may just mean that with a low tank one may not be able to rely on displayed estimated miles left!!!)

[hertsnminds]

You are right there, the miles left goes from 15 to -- with no stages in between, VERY scary when it first happens to you. I have been able to drive at least 20 miles with an estimate of -- and still never put more than 42 litres in what is supposed to be a 47 litre tank.

I have had a situation where I had 40 miles left (travelling at motorway speeds) then as soon as I came off the motorway I had up to 56 miles left. The computers are guessing all the time based on the current situation so only use the information they give as a guide they are not exact.

I also found I was getting much better mpg after the car had done over 10,000 miles. Not sure if this was the car bedding in or me getting used to how to drive it!

You will also notice that the car can never do less than 4mph, the speedo NEVER reads 1, 2 or 3mph.


Ian
Orange 03 Senso

[dave leatherby]

Ian - Still trying to understand the average mpg reading! Just could be that it isnt the average for the whole 250 miles - just the average at this moment in time. My former instrument tech employ was all analogue when a trim of the wick and a new flint (or a hammer) usually did the trick!!!

Had an early upset with lcd display - took grandkids to bird reserve - sunny day so on arrival fitted my clip-on sun specs - on starting back - horrors - display blank and black! - until I remembered the specs were polaroid (and display was dimmed when car was delivered!)

Will see how things proceed with current full tank.

Regards - Dave

[hertsnminds]

There are two answers to that...

We've got a full tank of gas, a half a pack of cigarettes, it's dark and we're wearing sunglasses. Hit it!

or

you were wearing...

[b]Peril Sensitive Sunglasses[/b]
Joo Janta 200 Super-Chromatic Peril Sensitive Sunglasses have been specially designed to help people develop a relaxed attitude to danger. At the first hint of trouble, they turn totally black and thus prevent you from seeing anything that might alarm you.

Depending if you have the Blues or you are a Hitchhiker

Ian
Orange 03 Senso

[dave leatherby]

Ooh! I'll have to get a pair of those sunglasses Ian!!!!

Hoping my slight increasing deafness will also eventually eliminate the b****y rattles from the B pillars as well - Think the French must be stone deaf from all the complaints about C3 rattles - perhaps the rattles are actually in French and are actually a soothing message - if I only knew the language!!!!

(Don't tell anybody - I drove car after 3 days unused and there was NO clutch judder!!!! - Reckon the car is saving itself to throw me a real surprise like brake failure or a wheel falling off or somesuch!!!)

Ah well - you can understand why the French had a revolution! B)

[dave leatherby]

Knew it was too good to be true Ian! Leap frog clutch back on form - beautiful judder today - think it's a design feature to make sure the B pillar rattles get a good freeing up so you really notice 'em at the start of the day!!!! B)

[hertsnminds]

Maybe you have an Australian model C3, built in Kangeroo Clutch B)

Of course if you think the clutch is more amphibian in nature you could say that was part of the cars gaelic charm


Ian
Orange 03 Senso

[dave leatherby]

I'll give it a little more time to see if it worsens Ian.

Originally I thought that all the early C3 problems I'd read about might have been sorted as time passed - looks like I was mistaken though!

Pity that my last (probably) new car is proving a real irritation. Guess I've been lucky 'til now. My last (Skoda Favorit estate) was a real good 'un - eleven years without any major problems and absolutely first class service from the dealer when required! (Despite all the jokes it was built like a Rolls in comparison!)

Doubt whether contacting Citroen direct would prove fruitful! B)

[CE08LDB]

My Friend had a S reg Jan 99 Skoda Felicia 1.3i then he had to renew it in Jan 02 So I told him to get a Saxo 1.1i Desire. He liked the Saxo but he prefered the Skoda he found it was bigger than the Saxo and faster. He only had one fault with the Skoda in November 2001 it had a leak in the sunroof but apart from that he said it was a great car. He is having A C3 1.4HDi Desire in Jan 05

[dave leatherby]

With so many miles on my OWN clock my old Skoda would have lasted me out - problem was that steering etc was heavy, especially parking and being an estate, and was getting a bit OTT for this antique mortal !

The C3 sensodrive was smaller, well equipped for the price, and, best of all, my wife could also drive on her auto-only licence! Am now weaning her back into road-craft after many years as a passenger only!

The C3 has been back to the dealer several times since purchase in July but, via the very kind saleslady who sold it to us, they've been very obliging. Pity about the rather poor construction and niggles, but the three year warranty will do us now ! B)

Regards - Dave