Fuel gauge sendiing unit E38

Shadsboat

Member
Hello,
My fuel gauge sending unit died and I am trying to replace. Anyone out there have experience? My tank is original 54 gallon on a 1984 E38.
Thanks,
Paul
 

Christian Williams

E381 - Los Angeles
Moderator
My factory sender was a float on a lever arm. Never worked because the arm hit a baffle in the fuel tank. Even if it had worked, it would not be remotely accurate given the shape of the tank. Vertical float designs have the same problem.

As I recall from other threads, there is a fuel gauge unit that meters flow, rather than measuring fuel level. I imagine that solves the problem.

I personally don't have a problem. No fuel gauge. An hour meter and a log book give all the information I need.
 

u079721

Well-Known Member
My factory sender was a float on a lever arm. Never worked because the arm hit a baffle in the fuel tank. Even if it had worked, it would not be remotely accurate given the shape of the tank. Vertical float designs have the same problem.

As I recall from other threads, there is a fuel gauge unit that meters flow, rather than measuring fuel level. I imagine that solves the problem.

I personally don't have a problem. No fuel gauge. An hour meter and a log book give all the information I need.
I guess they must have changed the mechanism over the model years, because ours (1989 version) was a float on a vertical shaft that turned the dial - and which was amazingly accurate. After our ~150 nm delivery up north each summer I would stop by the fuel dock, read the gauge (in sixteenths as I recall), convert to gallons needed, and then convert to liters, and be able to tell the attendant to within a liter or two how much we would take.
 

Shadsboat

Member
E38 Fuel gauge sender

My sender is/was a vertical tube with a float on two rails inside. Just wondering where I might find a replacement...
Thanks for the replies people!
P-
 

Loren Beach

O34 - Portland, OR
Moderator
Senior Moderator
I usually start with Defender.

https://www.defender.com/product.jsp?name=moeller-reed-switch-tank-sending-unit&path=-1|311|2349059|2349071&id=4520214

Steve is pointing out that you have to calibrate these float devices for our custom tank shapes. Start with empty tank, note how many gallons go in per unit of gauge measure.
That looks like the "WEMA" electric gauge sending unit in my 2008 tank. I recently removed it for chasing down a pinhole leak in the lower corner of the tank. Since our sender and gauge were supplied by the tank builder (Coastline Tanks in Bellingham WA), I wonder if they had a way/adjustment to calibrate it inside the gauge unit. It is actually quite accurate, seemingly allowing for the shape of the lower portion of the tank.
 
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