Ran Out of Fuel, Numbers don't add up - PeachParts Mercedes-Benz Forum

TDIRAD · #1 07-18-2008, 07:24 PM

I ran out of fuel the other night in my 91 300D. The low fuel never went on. It does light when the ign switch is turned to the first notch so I know the bulb is good.

I added 3 gals from a can and 14.4 is all I could fit at the pump, I could see the fuel in the neck so I know it was full.

My owner's manual says 18.5 for the tank and 2.4 for reserve. That equals almost 22 gals.

Is the owner's manual wrong? Or do I have some funny business going on?

Jeremy5848 · #2 07-18-2008, 08:24 PM

Since I don't have your owner's manual in front of me (a photo opportunity for you!!!) I can't say for sure, but might your manual have said "18.5 including a 2.4 reserve?" That's how my owner's manuals phrase it.

compress ignite · #3 07-19-2008, 01:19 AM

Also,I have good news for you...There is an easy fix to the ReServe Light...
You probably have an fungus/Algae infestation in the Tank(Black Goo)which
is preventing the Float in the tank sensor from bottoming out and closing
the connections on the ReServe light.

Condensation (There's no escaping it) and water in supply fuel collects in the
bottom of the tank...And provides a breeding ground for Algae in the Diesel/
Water interface.
See Attachment:

It will "Disable" the Algae (KILL) and should allow it to pass through the filters
and the engine.
(However,Semper Paratus [Always Ready] I'd carry a set of Primary and
Secondary filters with me...)

I was gonna say you can pick it up at any West Marine ,
However I see you're in Iowa.

Monday Give them a call (Nice People) They'll find you a retailer (or ship to
you)

Star brite Corporate Offices

4041 SW 47th Avenue
Fort Lauderdale, Florida 33314 USA
Phone: (954) 587-6280
Toll Free: (800) 327-8583
Fax: (954) 587-2813

Oh yes, caveat(s): Do Not Breath the concentrated StarBrite fumes!
Do Not Get StarBrite on Your Skin!

TDIRAD · #4 07-19-2008, 01:37 PM

Opps! Thanks for the reading/interpretation guidance.

Am I still a gallon short, could that be related to the algae and water at the bottom?

It did start right up after adding the fuel from the can, it sputtered a little, but nothing like when I ran out in my TDI, took like 20 mins of cranking.

The 2 filters? The white plastic 90 degree one and then the oil filter looking canister up front on top?

Hatterasguy · #5 07-19-2008, 02:42 PM

You can probably only burn down so far. It depends on where the pickup is, and I know on the W126 they have a little lip.

compress ignite · #6 07-19-2008, 03:34 PM

Yes,The little 90 degree plastic one is the "Pre-Filter" or Primary.
The "spin on" filters down to about 10 microns...and is called the
Secondary.

Hatterasguy and Jeremy are both correct.

No,If you had that much "water in the tank" and ran out of Diesel the last
sips the IP and engine got would be H2O AND They would be "F U".
The fact that it started so promptly tells us two things:
1. No air leaks between the "Fuel Sock" type "Strainer"
(in an upside down orentation) in the bottom of the tank AND the Injection Pump.(The fuel
system from the Tank to the Lift Pump on the side of the Injection Pump
is normally in a negative pressure [Suction] mode).
2. The Fuel Strainer in the bottom of the tank is not Too occluded by Algae.

The sensor for the fuel gauge is a long Aluminum Tube with Resistor Wires
and a float inside...BUT because the entrance and exit for the fuel are so
small...If there is ever an Algae infestation the Algae Corpus Delecti remain
trapped in the bottom of the tube...AND in your case dis-function the
reserve light contacts.The infestation may have been years ago or last
week.(OR you may be presently enjoying infection)