petrol gauge not working

i have a 1997 e36 328,the prtrol gauge hes stopped working. Its showing
empty & the red light is on but has half a tank left. The range on the
computer does not work either? any easy ideas to start with ?

There are two fuel level sensors, one in the left lobe of the fuel tank and
another in the right lobe. They can be accessed by lifting the rear seat
cushion out, and folding back the tar paper moisture barrier.

The left side sensor is a sensor only, the right side sensor is part of the
fuel pump assembly. In my car, it turned out that the left side sensor was
dirty, and cleaning it resolved the problem. Odds are that whichever sensor
you go after first, the other one is the problem. I think it was Murphy that
said that whenever you have a 50/50 chance of picking the right option, the
odds are 90 to 1 that you will pick the wrong option first.

Anyway, the float has a wiper thingie on it, and the base has a contact
strip. Using a business card (the course type), slip the card between the
wiper and the strip, and GENTLY move it around until you no longer get black
streaks on it. You can use Contact Cleaner as well, but you still need the
card to scrape away the gunk and crud. DO NOT BEND THE WIPER THINGIE, or it
will not make contact with the strip, and you will still have no fuel level
indication.






"bono" > wrote in message
lkaboutautos.com...
> i have a 1997 e36 328,the prtrol gauge hes stopped working. Its showing
> empty & the red light is on but has half a tank left. The range on the
> computer does not work either? any easy ideas to start with ?
>

hi thanx for the advice. ive found the sensors under the back seat but dont
know how to take them out. alls ive done is to unscrew the sensor holder
but i dont know wot to do next as i'm wary of pulling something which i
dont know enough about. wots the next stage, step by step?

"bono" > wrote in message
lkaboutautos.com...
> hi thanx for the advice. ive found the sensors under the back seat but
dont
> know how to take them out. alls ive done is to unscrew the sensor holder
> but i dont know wot to do next as i'm wary of pulling something which i
> dont know enough about. wots the next stage, step by step?
>

That's a difficult question. Go to amazon.com and order yourself a Bently
manual that covers your car. I have seen them listed on eBay.

Back to the question at hand,

BEFORE YOU START, YOU SHOULD BE SURE THE TANK IS NEARLY EMPTY. I reset my
trip meter each time I fill the tank, and I know I can average 25mpg, and
that I can carry 16 gallons. 25 x 16 = 400, so at about 350 miles into a
tank of gas, I went to work on the sending units. You can do this job with a
gallon or two in the tank, it would difficult with more than that. There is
an obvious fire hazard working around the gas fumes, so take the necessary
precautions of adequate ventilation, and smoking prohibitions.

The sending units (I suggest starting with the left one first since the
right one includes the fuel pump. Both come out the same way, but the one
with the pump is incrementally more difficult to handle.) come out by
unscrewing the ring. Of course, you have to disconnect the hoses and
connectors first. To remove the ring, I used a long extension to my ratchet
wrench and a small hammer to gently tap the vanes on the ring to knock it
loose. Once it comes loose, it can easily spin by hand. Take the ring off
and remove the sending unit. You have to move it around and squeeze it a
little to fit it through the hole. There is an O-ring that you will want to
be sure to not damage.

Once the sending unit is out and on your work bench, it is easy to find the
contacts, both the wiper part and the contact strip. I used a business card
to clean the wiper contact that is part of the float arm itself, and a
typewriter eraser (the pencil type that is very course and has the small
brush on the end). You can use any suitable tool, perhaps a very fine emery
cloth would do the trick. I also used Contact Cleaner as a solvent to carry
the dirt away. I used my DVM to test the continuity of the sensor circuit,
and when I had a reliable change in the DVM readings as I moved the float up
and down, I knew the operation was a success. Before I started, I recall
that I had flat resistance throughout all positions of the float arm; after
cleaning the contact wiper and strip, the resistance changed through a
relatively wide band.

hi,did wot you said & cleaned both senors but still no joy so it looks like
i'll need to take it in. Thanks for your advice & if you think of anything
else could you let me know. cheers

You will need to use your ohm meter on the fuel level sending units to see
which one is open.




"bono" > wrote in message
lkaboutautos.com...
> hi,did wot you said & cleaned both senors but still no joy so it looks
> like
> i'll need to take it in. Thanks for your advice & if you think of anything
> else could you let me know. cheers
>