Diesel Fuel gauge

[0149geep]

My fuel gauge is playing up at the moment and will not go below the quarter full mark at all which obviously means that when it reaches that mark then it becomes a bit of a lottery.
My question though is--Even though the gauge will never get down to the empty mark would the warning light still come on as it would if the gauge was working ok??This of course is important because if the light works independantly then I really can ignore the issue of the faulty gauge and carry on as normal.
Any answers please??

[Dragrad]

You have a diesel, NEVER allow it to go below a 1/4 tank, plenty of threads on this issue on here, mainly because of In Tank Fuel Pump issues. As for your specific question, we will need to await better informed members to respond I just drive her

PS, as your profile shows a Diesel car I have amended your thread title from 'Petrol Fuel Gauge' to DIESEL Fuel Gauge, If this is incorrect, please revise your UserCP and I will re-amend your thread title

[T-Cut]

The idiosyncracies of the fuel gauge are well known, but there's little in the way of explanation or how their strange behaviours can be fixed. The way the needle moves is controlled by the ECU after receiving two in-tank float signals. The floats seem to be the crux of the problems and can be due to misfitting after removal. They're very fussy about the way they lie in the tank and are easily fouled. They use simple a rheostat mechanism which sometimes goes wrong. Having said that, many gauge issues are unexplained. I suspect any reliance on the warning light will be unwise. I think it's tripped by the same float signals.

TC

[Mike Noc]

Originally Posted by Dragrad

You have a diesel, NEVER allow it to go below a 1/4 tank, plenty of threads on this issue on here, mainly because of In Tank Fuel Pump issues.

Yes don't go below a quarter of a tank if your ITP has failed, but with the LP fuel system working as it should then it isn't a problem.

If you never let the tank go below a quarter full you won't know when your ITP packs up.

[Avulon]

It is more likely that your in tank pump has failed. What makes you think the tank is empty? I'll guess that it's the engine cutting out. When filling up from that if you can't get nearly 65 litres in then it's not empty - If in fact you can only get 45-50 litres in then it's a sure sign of in tank pump failure. With a working pump as Mike already said then there's no problem running it down until the light comes on.

[DaPol]

[QUOTE=Avulon;2168223]It is more likely that your in tank pump has failed. What makes you think the tank is empty? I'll guess that it's the engine cutting out. [QUOTE]

*THIS*

Had just this issue with the GF's Connie a few weeks ago - the ITP had died and with a quarter tank showing she ended up on the side of the M40 waiting for the AA.

As ever, the test is to lift the squab off the back seat, and put your ear to the circular panel on the drivers side while somebody else turns the key to position 2 - you should hear a whirr and a bit of a "swoosh" from fluid moving - silence is a dead cert that the ITP is dead.

DMGRS of this parish sell Magneti Marelli replacement pump inserts for the ITP for reasonable money, and the replacement isn't too difficult as long as you don't mind getting up to your elbows in diesel.

[Avulon]

Originally Posted by DaPol

As ever, the test is to lift the squab off the back seat

Ever the pedant - since I was corrected and double checked myself. The test is to lift the base of the back seat...: the squab is the backrest... (I know, it's amazing how things get mixed up)