20 replies to this topic

[will.i.am]

i have checked through the fuel gauge sender unit threads and i am still abit puzzled as to what my problem is as mine is not mentioned,it first started when i got the mini,the fuel gauge would not go below half full when there was less in but worked if their was anything above half init,when you gave the car abit of toe the fuel gauge would go all the way to the top and stay their for abit until one day it went all the way to the top and now lives their when you turn the ignition on,doesnt matter how much fuels in it it will go as far to the top as possible,the temp gauge seems to read fine and sometimes reads a little colder than what it should but thats not very often,can anyone help?? i own a spi if it makes any difference

[Bounce]

Have you changed your sender unit?

Unfortunatly, for the SPI they not as cheap as the rest because it has to angle itself around the pump.

[will.i.am]

not so far because of the price,tis abit hefty,so i didnt want to buy one to find out it wasnt that

[Steamo]

While you are you saving for a new sender or diagnosing the cause, just carry a garden cane round in the boot dip it in the tank to check the level - my mates been doing this for months in his clubby estate.

Sorry I can't help with fixing it.

[AlexM]

is the sender unit properly situated in the tank? Their is a seal around it and the unit must be twisted in. Is it twisted all the way in so it seats properly, if it is loose it might cause a misreading problem.... (try this with an close to empty tank though) I think their may be a fuse for the unit in the engine bay, check it hasn't blown. (may well be an iinline fuse so might not necessarily be on the fuseblock.

[will.i.am]

cheers will it tell ya in the haynes where the fuse is?? or will i just have to look

[Bounce]

although i can see where your coming from summer, if the fuse was blown he wouldnt get any reading.


Fuel senders are basically variable resistiors. As the float on the sender arm moves with the fuel level, a wiper arm moves across a row of contacts.

If some of the contacts have broken through wear your fuel gauge will be acting strangely.


Im 90% sure you need to change the sender unit. I know its not cheap, just had to change mine!

[AlexM]

I spose if the fuse had blown it would just read empty, but it couldn't hurt to check.

[Bounce]

Fair one..... where is it?

[Dan]

Could be that someone has fitted a normal sender into the SPi tank and it's getting tangled round the pump gubbins inside. Or that it has been fitted at the wrong orientation as said above. Or the voltage regulator could be dead, how's the temp gauge doing?

Fuel sender is on the same fuse as the other instruments (except the tacho) and the ignition system, if one works they all will. If you want to check it's the line fuse with white and white wires.

Edited by Dan, 31 March 2006 - 04:22 PM.

[AlexM]

The inline fuses are here

Attached Files

•  IMGA0057edit.JPG   72.73K   3 downloads

[will.i.am]

thanks for the replys,very much appreciated,the temp gauge works pritty much all the time,it some times reads a little off if i have the internal heater on but thats another story.. and the inline fuses are all Aok because i checked them all last week so i'm thinking its the sender unit,not a cheap item compared with the old style ones but there you go

[m1n1]

of course there's nothing to stop you buying the older type, pluging it in to check it works.

if it does, remove your faulty sender unit. cut off the swinging arm.

cut off the arm on the one you had just purchased, then solder the old arm onto the working sender. soldering will work here, some years ago I bought a wipac universal fuel gauge/sender kit where the sender had to be soldered to the correct length (depending on the size of the fuel tank)


obviously you won't be cutting and soldering anywhere near the mini!

[AlexM]

There was one on ebay a short while ago, the seller was scrappin a couple of spi's i believe.

[pikey7]

I'm not exactly sure how the Spi sender looks and what part of the workings you can get to, (and as such, please wait for someone who has actually seen an SPi sender to comment before you do this), but I've done it on a few cars with fuel sender issues before and been successful!.

Before you actually start cleaning anything, remove the sender, plug it back into the loom, and switch the car onto pos1 (IIRC) on the ignition switch so the fuel gauge will work. Now move the arm up and down to check the readings. It may be something as simple as it getting stuck and by working it a bit, you may free it up.

Senders are basically a small copper "wiper" attached to the moving arm, and a variable resistor attached to the fixed housing. What happens is that over time, the contact and the wire et gunked up with contaminants in the fuel, and prevent a proper electrical contact from being made.

Using a toothbrush and some brake cleaner, brush over the contact and the wire (or it may be small copper "segments" which make the circuit to the resistor wire) to clean them. After a couple of goes, the brown gunky bits will become cleaner (although probably not shiny) and will allow a proper circuit to be made. When you've done brushing it over, blast the lot with cleaner to get rid of any loose particles and crud that may stop smooth operation. Now leave it a couple of minutes to allow the excess cleaner to evaporate off.

When you're working on any of this, remember that the fuel vapours are highly poisonous (so open the garage door!) and highly combustible (have an extinguisher handy!) and do any cleaning away from the car (brake cleaner and paint aren't mortal enemies, but they aren't on speaking terms)

Make a note of how the seal sits in, and make sure it's reassembled properly so you don't get any fuel leaks, and DON'T take anything apart on the sender unit unless you are 110% sure you can get it back together again properly.

Check it again by plugging it into the loom after cleaning and before you put it back in the tank too.

It may fix things, it may not, but if not at least you've not wasted any cash!