Author Topic: fuel gauge (Read 3934 times)

blysccr · « **on:** May 10, 2008, 08:19:13 AM »

91 318i. when i got the car, the fuel gauge was on half a tank, and it took 35 40 dollars to fill it up at 3.55 a gal. i doubt it hold 60 70 dollars worth. also, when i fill it up it sits right at full. so far, i've driven 100 miles since filled up, and it's still right a full. is this practical? i doubt it. also, how can i troubleshoot this? when i filled it up the first time, the gauge moved fine, and it goes way left when i turn the car off. thanks guys

RED IS 91 · « **Reply #1 on:** May 10, 2008, 12:23:58 PM »

It may be your fuel level sender in the tank or it may be a faulty gauge.
Do the rest of your gauges in the cluster work correctly ?
probably the level sender
http://www.autohausaz.com/search/product.aspx?sid=rqqff445zte1kx45pkiqqe45&makeid=800003@BMW&modelid=1011249@318I&year=1991&cid=22@Fuel%20%26%20Air%20System&gid=3331@Fuel%20Tank%20Sender%20(For%20Gas%20Gauge)

tjts1 · « **Reply #2 on:** May 10, 2008, 12:58:53 PM »

The fuel gauge is influenced heavily by lateral forces. If you turn left the fuel gauge goes toward full, if you turn right, it goes toward empty. Theres probably nothing wrong with you gauge. Drive it a few more tanks and keep track of how many gallons you use.

blysccr · « **Reply #3 on:** May 10, 2008, 03:19:08 PM »

i drove 200 miles and it's still at full....

RED IS 91 · « **Reply #4 on:** May 10, 2008, 04:03:38 PM »

Your fuel tank is 14.5 gallons IIRC .At 25 mpg(conservative),in 200 miles you'd have used 8 gallons meaning you should have less than half a tank.
You have a problem with either the gauge or sending unit or both.
I Wouldn't go more than 250-275 miles without getting gas.
good luck

Cobra Jet · « **Reply #5 on:** May 10, 2008, 10:43:26 PM »

Isn't there a ground wire to the back of the gauge (or cluster)?

The actual level sensor is easy to access or replace, it's under the back seat on the passenger side. You can remove it w/o having to remove the entire fuel pump assembly, it's only secured by (4) 10mm nuts (I think they are 10mm - if not, then 8mm).

I definitely would not travel any more than 275 miles or so since you cannot tell or know when the tank is actually going on empty.

blysccr · « **Reply #6 on:** May 11, 2008, 08:16:18 PM »

is there any way to fix it/troubleshoot rather than replace? i have a friend that's a tech and he is going to take my cluster and put it one some maching to see if my coding plug is bad or if it's my tach. can i also check my other gauges from that so called, machine? thanks

colin86325 · « **Reply #7 on:** May 11, 2008, 08:33:02 PM »

You can pull the gauge cluster and brighten all the ground contacts, including the underside of the nuts.
Also the sender unit in the tank is mechanical, so that means if there is binding on the float mechanism, you will not have a correct signal at the gauge.

318i91 · « **Reply #8 on:** August 16, 2008, 10:38:39 AM »

I read many threads about gauge showing empty on a full tank. But is it possible to have a fuel gauge pointing about 2/5 full with an empty tank? I am asking because I couldn't siphon even a drop out of the fuel tank while the gauge consistently settle at the 2/5 position when the key is turned "on".

Thanks

colin86325 · « **Reply #9 on:** August 17, 2008, 01:56:59 AM »

Sounds like your fuel level sender needs to be replaced or cleaned.

Jimmy Lewis · « **Reply #10 on:** August 17, 2008, 04:12:37 PM »

My car does the same thing, when I fill it up it shows full, but it scales empty to halfway. It is very consistent and at 3/4 a tank I have about 1/2 a tank. As much as I would like it to work correctly it doesn't bother me enough to pull the cluster again.