fuel gauge problem

OC e39r · Jul 15, 2008

this is my first problem to encounter with my newly acquired 03,it is bone stock with 47,xxx on the clock.
Today after a long day at work,I jumped into my car and turned on the ignition and surprisingly the gas light is on and the dial is on e. I was 100% sure it has 1/3 or a little over when I parked earlier, so I backed up to check if there was any leakage on the ground...negative and no gas smell to be found, anyways I drive it to the nearest chevron to put gas.when I did, the pump stopped at 12 gallons not 18!!! I turn on the ignition to position 2 and the dial is not moving past 2/3!!! I drove it like 5 miles and the dial reading started moving slowly towards F but never reached the end.
wt r we looking at here? the car is still under CPO for another year so I hope it is not a biggie.
forgot to say..there is no codes or lights,and of course the gauge light went off after I put gas.
regards

jclyman · Jul 15, 2008

You need to understand how the fuel system works. I have written more than one post on how the system works (You will need to do a search, as it has been some time ago).

You will need to check console Test # 14, if I recall correctly (it requries unlocking the console, which has also been written about extensively). It has 5 positions for error codes. If one of the codes starts with a "D7," your left hand tank fuel pickup and float are failing. There is also a test that will tell you how much fuel is left in each tank (Again, I think it is either Test # 4 or # 6).

If it is the left hand tank sensor (my bet, since you couldn't seem to fill it up ... even though it was actually full), it isn't terribly expensive, if it is not covered by your CPO. And, you could replace it yourself, if you are handy with mechanic's tools.

BMWMPWR · Jul 15, 2008

jclyman said:
There is also a test that will tell you how much fuel is left in each tank (Again, I think it is either Test # 4 or # 6).

To confirm, test 6 indicates current fuel level in each of the two tanks. Left and right will add up to no more than 65 liters although filling a full tank gives you slightly more than the given 65 liters roughly 17.17 gallons.

chowdah · Jul 15, 2008

Nice detail. I personally would not be too concerned at this point. Others (search) have reported their fuel gauges showing moments of passing insanity too.

Monitor Test#6 closely to measure the health of your pumps. You are watching for the 34 to go to 0, then the 31 to start decreasing. At that phase, you should see g-forces shifting liquid that is pumped back to 0 over several seconds' time.

FYI, I've seen the BF and D7 DIAG# order inverted compared to you. We haven't figured out what all the first 4 character combinations mean, but we think the last 3 are some kind of counter (translating "000" to "don't worry about it" perhaps).

The "155" tells you: you had a hiccup. These errors are not significant enough to show on our home scanners, but a dealer's fancy one may tell you something. Let us know if you find out.

gsfent · Jul 15, 2008

chowdah said:
.

Monitor Test#6 closely to measure the health of your pumps. You are watching for the 34 to go to 0, then the 31 to start decreasing. At that phase, you should see g-forces shifting liquid that is pumped back to 0 over several seconds' time.

When your left tank gets to 0, your right tank won't budge from 31L for about 20-30 miles of driving. When you get to about 12L, the gas light goes on.
The first test on #6 shows the two halves, with each reading as noted above. If you go to test 2 on item #6, it simply shows a damped out single number of Liters remaining. About 3.8 Liters per gallon.
Regards,
Jerry

ard · Jul 15, 2008

Isn't there a transfer pump that moves fuel from left to right? and if the pump starts flaking, you can still have fuel (in this case still in the left tank) but run out?

jclyman · Jul 15, 2008

yes, but it seems to be all in one inexpensive unit.

OC e39r · Jul 16, 2008

ok,just came back from the dealer's.The receipt says...checked for faults found FC9.Tank sensor shot to positive store in the inst. cluster .next removed rear seat and checked resistance of fuel sensor 2 found cycle from OL to 412 k ohms. Defective fuel sensor( carbon deposit on the sending unit). sensor 2 is replaced.part number 16 14 183 179 left fuel L1.
Parts and labor covered under CPO.
Before leaving the dealer's I ran the console tests 14 and 6.As for 14 ,DIAGS from 1 to 5 are all zeros, and for 6 ,both tanks read lower levels-before only the left tank level was declining. I asked the SA about the BF code,and the 155 but no answer. The hiccup is gone,although it was not that bad before,but the progress is noticeable
Thank you all for ur posts,and I hope this threat will be helpful for someone in the future..:cheers:

chowdah · Jul 16, 2008

OC e39r said:
ok,just came back from the dealer's.The receipt says...checked for faults found FC9.Tank sensor shot to positive store in the inst. cluster .next removed rear seat and checked resistance of fuel sensor 2 found cycle from OL to 412 k ohms. Defective fuel sensor( carbon deposit on the sending unit). sensor 2 is replaced.part number 16 14 183 179 left fuel L1.
Parts and labor covered under CPO.
Before leaving the dealer's I ran the console tests 14 and 6.As for 14 ,DIAGS from 1 to 5 are all zeros, and for 6 ,both tanks read lower levels-before only the left tank level was declining. I asked the SA about the BF code,and the 155 but no answer. The hiccup is gone,although it was not that bad before,but the progress is noticeable
Thank you all for ur posts,and I hope this threat will be helpful for someone in the future..:cheers:

All as jclyman said it would be.

Nice quick concise action all around. Thanks for the follow-up.

Carbon is to blame huh. Nothing in there about the pump (pn 16116752839)?

ard · Jul 16, 2008

I would not be surprised if the dealer network has no info on the OBD codes.... they have no reason to use them, since they have access to the DME/GT1 tester.

Mine was done under CPO as well.

A

fuel gauge problem

Our Vendors

Top Contributors this Month

Recommended Communities