TZD Fuel Tank Capacity

[roscoe]

I have a question about the fuel capacity/gauge reading on a TZD. Mine lists the tank capacity as 14.5 gallons/66 litres, but the most fuel I've ever been able to put into it is abour 45 litres and that is with the fuel gauge barely moving off empty when running. I've changed the tank sender unit and the replacement one is the same as the original - shows dead empty, yet I can only get around 42-45 litres into it. Does the fuel gauge only read capacity down to the reserve level (about 2.5 gallons or so I think) or do I have a mis-reading fuel gauge? Anyone else have this on their BX?
I figure I should be getting around 650 miles per tank but only get about 450 and the gauge is pegged on empty - and I've been afraid to push it and run out of fuel...

[Geoffrey Gould]

Hello Roscoe That does seem to be about right, I have never yet found a BX gauge to be that accurate, mind you Iv'e never fitted a new one so they have always been 10 years old +. I always use mileage as a "gauge" 10 litres to 100 miles, the gauge on mine once it gets below 1/2 flicks anywhere between 1/2 and a 1/4 and empty as it feels like.
Has anyone fitted a New sender and if they have what happened?
Cheers.
Geoff.

[DLM]

Tank senders are fairly basic units, prone to both wear and tear of the contact strips and sticking. I doubt that a new one (if economic) would make much of a difference. If it really bugs you you can find the amount of diesel left when the gauge registers empty by removing the sender and siphoning out the remains, assuming you've got a way of measuring this. Once on the warning light, remaining range is in the region of 100 miles, which fits well with Geoffrey's rule of thumb.

In fact, Geoffrey's rule of thumb is the one I always use as well.

[roscoe]

Thanks folks - so I should be looking to fill up at around the 550-600 mile mark which would leave a sufficient reserve capacity. The sender I replaced the original one with was from my 16V parts car - I took it apart and all the wires on the circuit board were fine, so I had more faith in it than my original one which was totally knackered - most of the wires were hanging off the board or wrapped around the float contacts.
My fuel gauge is pretty stable now -very seldom jumps around but shows empty at around the 425-450 mile mark. Strangely enough, my 16V used to show the same range (only in kms) when it was empty as well and never took the full 66 litres either, so it must be another Citroen 'idiosynchrasy'...or just bad design.

[docchevron]

Ah yes, citroen fuel gauges. Never found one accurate yet in any cit.
My diesel has the 10 gal. tank but I've never managed to get more than 7 in it, even when the b*gg*r ran out of fuel on the motorway I could dtill only get 7 in it!
Dont tend to look at the gauge in the 16v, I just stop at every optimax station I drive past and empty my wallet into the tank!
I'd have thought 600miles to a tank in a TD would give you plenty of reserve to get to a filling station
Cheers
Chris G

[tom]

There is a logical reason for all this. When the tank capacity needed to be increased from 50 to 66 litres, Citroen produced an extra tank to extend the range. They didn't change the sender, though so you will have a "Full"tank reading for about 130 miles before the gauge starts to fall if you have the big tank.
If you cannot get more than 45 litres in, it may be that your car does not have the 66 litre tankage and I suspect that your gauge will be much more linear.

[Vanny]

Glad to know im not the only one that uses the ole £10 to 100 miles rule, never comes out like that but its a damn good guage!

My record is 61 litres in one filling, and i had done over 50 miles on a solid light by then, thought that was pushing it a bit but i guess not

On the topic of naff french guages, my dads last Picasso (51 plate) had to go back three times before they got the guage to work anywhere near accurate! These being digital have a reset precedure for the guage but the end solution was to replace the display screen and computer, under warranty!

So far in my driving history i have never run out of fuel, it has always baffled me why people run out!

[Ian_Fearn]

My TZD is doing around 140 miles to £10. Best car i've EVER had on fuel and it goes like stink too!!!

[Geoffrey Gould]

Hi Vanny it beats me too, I did lend a Morris 1000 to someone once with the warning that when the needle was on Empty then indeed it was empty. No prises then in guessing who ran out on the motorway -- they did. The best thing was that they repaired Morris's for a living.
Cheers.
Geoff.

[sleepy0905]

Well i have discovered that my TZS is not as thirsty as i thought it is just the guage under a 1/2 does what it bloody likes so i am now on the lookout for a replacement sender unit.

[cavmad]

This `extra tank` mentioned, is that a reserve tank which is seperate to the main one?
I removed one from my old estate as a possible future spare, hence me asking.

[sleepy0905]

Thats correct billy it is strapped in the wheel arch behind the back bumper you know the bloody thing we had to chisel off and took absolutely ages.

[jeremy]

The extra tank is not a reserve tank. Reserve tanks are a separate supply - so you run out on the main tank and switch over to the reserve, and curiously those vehicles fitted with a so called reserve (60's Rovers, Triumph Herald?) in fact only have a single tank with 2 pick-ups, one being shorter than the other. Fuel runs low, short pick up comes out of the fuel and air is drawn in, so block short pipe with an electrically operated valve - and draw off the bottom of the tank.

Then someone invented the low level warning light . . .

Many Jaguars in fact had 2 tanks of about equal size in each back wing - and you could draw off either by operating a dash switch. I was never sure if I liked it or it was a nuisance having to fill 2 tanks as there was no transfer pump.

The BX additional tank simply adds capacity - and is simply connected to the main tank by a piece of 1 1/2 inch diameter hose with no valving or anythiung else.

[roscoe]

My TZD does have the additional small tank and I'm getting around the 130 mile mark before the fuel gauge moves off full, so this time around I'll run it up to the 600 mile mark and see if the (never seen before in real life) low fuel light comes on I know it works as I've tested it with an earth from the sender plug under the rear seat.
Interestingly enough, I filled up last night and checked my mileage - 45 mpg or around 4.8 l/100km, which is worse than I normally get - but I've been flogging it back and forth to work lately - about 20 miles freeway driving each way at ~125km/hr and 20 miles of city driving which is mostly stop/start. Also need to change my airfilter - it is getting dirty.

[tom]

Your figures are spot on Roscoe. These are the same as I get from my own TZD.