[ccrobin]

Hello,

I just acquired my first Benz, and I love it.

As I am trying to exorcise the demons, I am having particular difficulty with the fuel gauge. It usually is not working (reads completely empty), but as I am driving it often jumps around erratically, and sometimes even appears to be working. I am suspecting that I should first check the ground wire of the sending unit, problem is I can't find it. I have looked in the trunk without success. Do I need to remove the back seat to access it? The other posts and diagrams I have found were not clear to me.

Also, any suggestions as to wire color(s) and locations that I should check for the fault?

Thank you much!

 

[ccrobin]

bump.

 

[Jankebenz]

Very common for the fuel level senders to fail, i dont think there too expensive. I believe if you take out the medical kit you will be able to remove the sender. If i remember right its 27mm or 32.
Adriaan

 

[NYw126-91]

Fuel electrics

Very common for the fuel level senders to fail, i dont think there too expensive. I believe if you take out the medical kit you will be able to remove the sender. If i remember right its 27mm or 32.
Adriaan

The grounds are usually Brown and many are gathered together at certain areas on the body. A manual will help with this search.

 

[roadhouse]

I guarantee you it's your fuel sender, which is a very easy fix. (On the coupes more so than on sedans). You access it by removing the rear seat. You'll find it under a plastic cover plug approx 4" dia on the top left.

You may want to remove the sender, disassemble it, and just simply clean it. It may be full of sediment and/ or rust.

 

[NYw126-91]

Fuel sender

Ohh One more thing...disconnect battery. Do you know the radio code?

 

[SDLCrazier]

Ohh One more thing...disconnect battery. Do you know the radio code?

he is using an aftermarket radio so no code.

 

[ccrobin]

Thanks all! I will try looking under the first-aid kit to see if the sender is there. I'll try cleaning it first, but I am assuming that because of the way it seems to "click" on and off that it is probably not the unit gummed up (it actually seems to be very accurate when "on"). I will investigate and post my results.

 

[ccrobin]

The grounds are usually Brown and many are gathered together at certain areas on the body. A manual will help with this search.

Thanks! This tidbit will help!

 

[roadhouse]

no need to disconnect the battery, as long as you leavce the key out of the ignition.

 

[ccrobin]

no need to disconnect the battery, as long as you leavce the key out of the ignition.

OK, thank you!

 

[ccrobin]

UPDATE:

OK, I ended up pulling the fuel tank to rinse it out (kept plugging fuel filters).

While it was out, I removed the sending unit and found the metal tube from an old unit had broken off and was floating around inside the tank. I spent about an hour getting the dang thing out, put everything back together, and still have the same problem.

When driving I notice that if I hit bumps the gauge will start working, hit another and it stops. Out of curiosity, I tapped the dashboard above the fuel gauge and it seems to have made the needle jump. Is it possible that it is my gauge (and not the sending unit) that is bad? Any way I can test it?