Full Tank of Premium and Guage reads "Empty" - PeachParts Mercedes-Benz Forum

#1 05-10-2005, 10:48 AM

I did use the search function and discovered many issues similer but not exactly like mine. As stated i filled up my tank and while driving noticed the fuel indicator move from full to empty gradually over 2-7 minutes. When i parked the car, left it for about 20 minutes and restarted i had a full tank again with the same process bringing me to empty. Any feedback would be greatly appreciated. Posted this in the Tech forum as well

Thanks in advance gentleman

2001 ML55

mbdoc · #2 05-10-2005, 11:09 AM

The fuel tank sending unit is part of the fuel pump assembly.
It can be tested at the wiring harness going to that assembly.
Resistance in OHMs is 200 empty & 1 full, of course +- 2 ohms at either end.

#3 05-10-2005, 11:19 AM

Can i purchase the sending unit separatly, perhaps a DIY?

Where is the access to the unit located

Tks Doc

#4 05-10-2005, 12:01 PM

MB DOC - Do you know Hanz over at Helms, Bayside? Good Fella!

ILUVMILS · #5 05-10-2005, 12:19 PM

Depending on your VIN# the instrument cluster may need to have some of the version coding changed. MB issued a bulletin about this some time ago. Any dealer should be able to tell you if you're a candidate for this fix.

Bill Wood · #6 05-10-2005, 07:05 PM

Quote:

Originally Posted by SilentMethod

Can i purchase the sending unit separatly, perhaps a DIY?

Where is the access to the unit located

Tks Doc

It is under the back seat. Inside the fuel tank. Not an easy fix for a DIY'er.

#7 05-11-2005, 10:10 AM

I opened up the gas cap, and let the car run for a minute or two and the needle went zooming up to full again. Wifey is driving the 55 today so i dont know if it permanantly corrected the problem. Feedback appreciated. Can it be a gas cap issue or lack of pressure?

#8 05-20-2005, 01:46 PM

Problem Fixed - It was the gas cap. Apparently theirs a rubber strip that runs the interior that completes an air tight seal. Changed the cap and problem fixed.

Thanks all with the help

Smith007 · #9 05-23-2012, 12:13 PM

ML 320 2002 (possibly manufactures in 2001) Km 200 000
Issue: fill car with fuel from near empty and know the guage sits on reserve or amber light on occasion on start up the fuel gauge returns to normal for short period then returns to amber light reserve
Possible solution:If my interperation is correct fron the great posts is to pull the fuel pump sensor fuse wait a few seconds?
If the problem persists check the wiring connector under the left rear wheel arch for corrosion?
If wiring is good do a multimeter test like Doc said?
If the above readings are good -- just replace the fuel pump???

Smith007 · #10 05-28-2012, 10:15 PM

Pulled the 20 amp fuse TWICE
(situated on the side wall on the passenger side) for fuel pump now the gauge is reading correctly thank you so much!!!!
Hopefully longterm fix

Smith007 · #11 05-30-2012, 08:54 AM

Well the fuse switch only lasted a few hours
Next step i guess

Smith007 · #12 06-19-2012, 02:37 PM

Just heads up - - some useless information perhaps
I was looking to prep - so as to remove the air blend flap motor under the dash board
SO I HAD TO DISCONECT THE BATTER NEGATIVE CABLE and AT THE SAME TIME I REMOVED THE FUSE FOR THE FUEL PUMP when i reconnected all the gauge was working showing 3/4 tank