Fuel Gauge gracefully goes to Empty, within 11 gallons. - PeachParts Mercedes-Benz Forum

Bstef · #1 09-30-2007, 02:12 PM

When my fuel gauge reads empty and I go and fill the tank,
I can only get 11 gallons into the tank.

This means there are 10 gallons in my tank when it reads Empty,
correct?

Thought my mileage was really horrid for a moment....

There is no gunk in my prefilter.

I do have a 21 gallon tank right?
Does this seem to indicate a floater has repositioned itself?
The fuel gauge does use a floater, yea?

What Kind of job am I looking at here timewise...
Im wondering if adding an hour gauge would be easier-
Than I could just kinda Time the rest of the tank....
wow im lazy.

I searched the threads but havent found a gauge gracefully going to E at half a tank...

Tx!

TheDon · #2 09-30-2007, 02:20 PM

ok... here is what to do

remove the med kit box

notice the large sending unit with the plug on top.. unplug it

use channel locks and remove it (I had to removed the trunk bulkhead to remove it.

carefully remove from car.. towels should be placed on the seats to catch diesel

the unit has a nut on the bottom.. its a plastic nut with a metal one inside of the plastic.. remove that and carefully slide the metal sleeve off..

be gentle and clean the wires... mess those up and you are sol

then move back to the canister and clean that as best you can.

(notice the small drain hole on it.. thats where the diesel enters and leaves so your guage will show the fuel level.. if its blocked it will register wrong)

reinstall and report back..

if it still does it.. it is either a faulty gauge or an imploded tank

it is around 21 gallons counting the reserve. my tank will fill up to 20 gallons when I run it 60 miles with the R light on

Adenauer · #3 09-30-2007, 03:53 PM

So in an '87 300D, at what point does everyone's R light come on...where is the needle on your gauge sitting when it comes on?

argus445 · #4 09-30-2007, 05:16 PM

Quote:

Originally Posted by Adenauer

So in an '87 300D, at what point does everyone's R light come on...where is the needle on your gauge sitting when it comes on?

Is there a red light comes on? i debated if there was or not it mentioned it in the owners manual haven't ever seen it before and i've gotten it down to less than 2 gallons when i flushed my tank out. Wonder how u could test the light see if it's working or not? or when does it normally come on

pawoSD · #5 09-30-2007, 05:27 PM

The light should be on when you are glowing before starting the car and then should go out. It does not on my car, but it does on my dad's and our 300D, however, neither of their senders will activate the light, even when run to almost no fuel left....probably sludge in the senders.

I bought a couple gaskets for the sender, so I might try and pull/clean mine next saturday....we'll see how that goes....

Mine will read fine from Full to half....then it stays at half till the tank has about 1/4 left, then it will fall to 1/4, sometimes jumping back to half....then when its really low it goes down just above R and stays there. Probably messed up/gunked up inside.

Adenauer · #6 09-30-2007, 05:37 PM

An '83 240D I had did almost exactly the same thing. I pulled the sender and found what looked like tool marks from a pair of channel locks around the aluminum body of the sender. Go figure. I threw a sender in place from a boneyard car and never had another problem with how the gauge read.

vstech · #7 09-30-2007, 06:31 PM

you may have collapsed your tank, pop your trunk and look behind the carpet against the front bulkhead, you will see if the tank has collapsed. if it has, your tank vent has plugged up.

Johnhef · #8 10-01-2007, 08:25 PM

if the tank isn't collapsed- It's possible you may have a sender for a wagon installed, the wagon uses a significantly shorter sending unit, but with screw in a sedan tank no problem.

for the 87 300D question, mine sits on the "R" line for awhile before the light comes on.